Mothball One

2012 Projects

2011-10-06T07:32:00.002-06:00

Now that Mothball 1 is stripped down for the season I’m starting to think about improvements and mods for 2012. Some of the modifications I’ve already started. Let’s start with foils. After checking out the information on Bruce McLeod’s blog (http://www.teknologika.com/mothblog/the-evolution-of-moth-main-hydrofoils/) I concluded that my main foil was too big. It was about 10% larger than the Bladerider main foil. Enter Mr. Dremel. After inspecting the foil and comparing it to all of the other foils out there I decided that my flap was too large, in particular at the tips. I couldn’t take too much off the flap, but I did taper it down 10mm at the tips. This should bring the flap into better proportion with the cross-section of the rest of the foil and reduce drag. Tapering the flap reduced the total area by 5%. I’m considering cutting the tips down a bit to reduce the area even more, but I may wait a bit for that. Does anyone know the approximate area of the M2 foils?

I’ve also decided that I want a ride-height adjuster. I can get good height, but it seems like I always have more height sailing downwind. If I set the height for downwind then I’m a bit low upwind, and if I set it good for upwind then downwind is horrifying. Is this normal? I saw the ride height adjuster on Sailingbits.com (http://www.sailingbits.com/catalog/moth-ride-height--gearing-adjuster-p-377.html). Does anyone know if this adjuster will fit onto Bladerider components? Seems like buying one of these would be way easier than developing my own system.

These are my only two big planned changes. I want to refinish the hull and make some other minor repairs, but these are relatively easy. My hope for 2012 is to get things sorted and then make it to some Moth events on the west coast.

End of the Road

2011-10-03T19:51:00.001-06:00

This weekend was the last mothing in Montana, and a beautiful weekend it was. The breeze was a bit variable, but I did get a few good sessions. My last sail was in 7-10 kts of breeze and I logged 14 miles in 1.5 hours at an average speed of about 10 kts. I also pulled off four fully jibes and didn’t ever get the sail wet. I’m to the point I’d feel pretty comfortable taking Mothball 1 somewhere to race and I don’t even think I’d embarrass myself. But for now it’s time to start thinking snow (forecasted for Friday). Mothball one will be fully stripped down and prepared for a full refinishing next spring. I have some ideas for mods and new parts, but I’ll save that for another day.

A Day of Many Firsts

2011-09-25T20:47:00.004-06:00

I had a lot of new and different experiences today on Mothball one, some of the experiences were good, others not so much, but I ended the day with a smile. I went out this afternoon with 8-10 kts of breeze and quickly had my first new mothing adventure of the day. I was sailing towards the shore and knew there was a shallow spot somewhere. I was about to turn when I looked down and saw the bottom way too close. I quickly thought about whether it would be better to keep foiling and pray that I make it over the shallow spot or just eject and hope for the best, but about one second later the decision was made for me as the boat hit the ground and I was shot into the water. I stood up in the thigh deep water and was feeling pretty stupid, but after some inspection I realized that the damage was fairly minimal, just some scratched paint and a small crack at the end of the daggerboard box. Lucky. The wind was still nice so I just swam out to deeper water and took off again and kept sailing for another hour.

The wind started to die so I went in to take a break. The wind was forecast to come up later in the afternoon so I stuck around to wait for it. It took some time, but the wind finely came up late in the day. I sailed upwind with some good pace into the building breeze. The wind was blowing down the entire 30 mile length of Canyon Ferry Lake and with the wind increasing to 15 kts the waves started building quickly. I sailed upwind for about three miles and then turned around with the wind still increasing. By the time I was heading back down the lake the wind was gusting to 20-25 kts and the waves were getting quite big. This was the first time I’d ever sailed downwind in big waves. I hit a max speed of 19kts in the lumpy seas even with my scratched main foil. After launching over a big wave I did my first high-speed ventilation of the main foil and crashed rather dramatically. I crashed several more time before I figured out how to drive the waves to avoid the big breakers.

As I was getting back to the marina the wind had decreased to around 15 and the seas had flattened quite a bit. I had to make three jibes to make it back to the docks and I was hopeful that I could end this exciting sail with a foiling jibe. I went into the first jibe feeling good and the boat stayed flat and fast. I got to the other side in position and sheeted in and kept sailing. Yay! First foiling jibe = DONE! My next jibe didn’t go quite and well, but I was able to stay up on the last jibe too.

So it was quite an exciting day on many levels. I tried to ruin my boat, but didn’t, I sailed in big waves and survived, and I made two foiling jibes. Too bad this sailing season is almost over, this is getting fun!

20 Knot Barrier = Broken!

2011-08-24T21:44:00.001-06:00

I know that doing 20 kts on a moth is really nothing special, but breaking 20 kts on homebuild with homemade foils is still pretty cool in my book. I went out tonight expecting to a 10-15 kt breeze but was pleasantly surprised with a 10-20 kt breeze with some higher gusts. On two separate runs I recorded speeds on the GPS of over 20 kts with a max speed of 20.9 kts. The boat did very well, but I felt like I needed to change my pants afterwards. No matter how you cut it, 20 kts over the water is really fast. I can’t hardly imagine what 30 kts is like.

I’m getting closer to the illusive foiling gibe too. On two different attempts tonight I stayed flat and on the foils all the way through the jibe only to fall off at the very end due to not enough wind and speed. I’m not there yet, but I’m getting very close...

Cascading Failures

2011-08-23T15:54:00.002-06:00

It’s amazing how small breakages can instantly get worse. I was out sailing last night in some nice 10-15 kt breeze and the boat was felling really good. I made a high-speed pass of the shoreline and suddenly BLAM the vang explodes. The boat goes instantly out of control and I spin and crash fairly violently. A quick look at the vang confirms that one of the small attachment lines has worn through and exploded. No big deal, I can re-tie it on the water and keep sailing. After fixing the vang I take off again but the rudder has a terrible vibration, something is clearly very wrong. I stop the boat and go back to check the rudder, everything looks ok, but on closer inspection I see that the rudder has split down the middle. You may remember that the daggerboard did the same thing to me last year but I was able to fix it and it hasn’t had any trouble since. But it’s strange how a simple broken line on the vang can cascade to a broken rudder. I’m really hoping that I’m running out of things on this boat that can break, but I shouldn’t be too surprised about failures as I start to push the boat harder. Thankfully this is another easy fix. Test, learn, improve.

I did find the cause of the mysterly leak too. There was a small crack in the chine below the hole that my brother put in the side with his head. Right now its fixed with a piece of tape. Yet another easy fix :)

Mystery Leak ?

2011-08-15T07:58:00.003-06:00

Mothball One spent most of the day in the water on Saturday. It was a nice day but not much wind. I went out several times and chased some Fins around and let my brother take the boat out. The hull was in the water for about 8 hours and most of that time it was upright. When I took the boat out of the water and opened the drain plug I was greeted with a puff of air from the plug hole indicating that the hull was still sealed and pressurized. But then I started moving the hull around I heard water sloshing around. I tipped the boat up and got about a liter of water to drain out. So here's the mystery, how did I get water in a hull that appeared to still be sealed and pressurized when I took it out of the water? This is the first time I've ever gotten water from the hull after a day of sailing that I couldn't explain.

Wand Tension ?

2011-08-08T11:24:00.001-06:00

I've been looking around for some insight on wand tension but I'm not having much luck. Specifically, how much wand tension should I be using for different wind conditions, upwind vs. downwind, flat water vs. waves. How much tension is too much/too little. Anyone have the answer to these questions?

More Broken Bits

2011-08-03T21:38:00.004-06:00

I am truly amazed how many things you can break on a moth. I spent a lot of time on the water last weekend in a variety of conditions, everything from 5 to 25 kts. Thankfully nothing actually broke on the water. I was hoping to take Mothball 1 up to the Montana Cup this weekend so I broke everything down after sailing and inspected everything and made a list of repairs I wanted to make before trying to race the boat. Here it is:

1. Fix ripped grommets in the tramps

2. Reinforce vang mount

3. Reinforce forestay attachment

4. Repair rack joints

5. Replace mast rotation pin

6. Reinforce gantry attachments

7. fix wand tip

8. Modify spreader attachment

9. Fix rudder pintle holes

Luckily all of these are easy fixes. I'm hoping that I'm running out of parts that can break. Unfortunately I don't think I'm going to make the MT Cup afterall, but its nice to know that I'll be ready next time...

Video (Finely)

2011-07-24T14:48:00.005-06:00

It took a few more days than I was expected to get this video, but I think it looks pretty good :) The video was taken from a moving boat so it looks a bit slow.

That's Using Your Head

2011-07-17T20:32:00.004-06:00

Mothball one is look'n pretty good, despite some minor injuries. My brother Jeff was jones'n to take the boat for a spin on Saturday evening in some pretty good breeze. Unfortunately his ambition did not quite match the conditions and after accidentally letting the cunningham completely free and not noticing, the boat became pretty uncontrollable in the 20kt breeze. After crashing several times in a row he ended his ride by falling backwards off of the racks and landing head-first on the hull. It was a pretty violent fall and he hit hard enough to put a pretty good crack in the hull. Thankfully he wasn't hurt and after making a few rig adjustments I was able to sail the boat back to marina and I even got it on video (check back tomorrow). After fixing the boat with some sail tape (see above) I sailed some more this afternoon in a pretty nice 8-10 kt breeze. Thanks to Valerie for the pic and movies!

Broken Butterfly

2011-07-09T21:21:00.004-06:00

Today was another good day for mothing. After dorking around in some light winds this morning the winds came up to a good 20-25 and Mothball One was put through her paces. For the most part the boat was handling the conditions pretty well and I went out several time and worked on upwind and downwind handling. Gybing still totally eludes me. Everything was feeling really good, until everything came apart. On a good fast reach back towards the marina I heard a loud crack and was instantly in the water. It was pretty clear what had happened. The rear rack arm had completely failed. Thankfully I was at the mouth of the marina and I was able to drift/swim back to the dock. Somehow in the process of the crash I broke the rudder off too. I'm not sure if it was breaking before the crash or if I landed on the rudder foil when the rack broke.

Sometimes I wonder why I don't get discouraged when Mothball One breaks, which it has many times. But at the end of the day I think its all part of the process. You can't push the limits without experiencing a few failures. But every time you take off and fly on a boat that you made, the fact of failures don't seem so bad, at least that's what I'm telling myself :)

I love teflon tape

2011-07-01T07:13:00.002-06:00

Thanks everyone for replying to my last post about how to fix my rudder. The repairs have been completed and I'm pretty confident that its going to be quite solid now. I went to a longer and larger screw (1/4" x 2") and wrapped it with carbon uni and tapped it firmly into the hole. I did have some fear about epoxying this huge bolt into my rudder and just praying my release agent would work. I was also a bit concerned about making it so tight that it would be a huge pain to get it in and out again. Enter my trusty roll of teflon plumbers tape. One thin tight wrap of teflon tape around the bolt over the release agent and I was pretty certain the screw would come out relatively easily. I did take some time to force the tape tightly into the threads of the bolt and then wrapped it with carbon. The bolt was still quite snug unscrewing, but it came out smoothly and the threads look really good on the inside. I also use teflon tape on all of my screw connections and linkages for the wand connections. It just makes everything tighter and more solid while also ensuring that you'll be able to take it apart again. Its good stuff, you should have some in your toolbox too.

Bob's Lucky Day

2011-06-26T17:26:00.003-06:00

Yesterday was a good day for mothing. After completing a 14 mile keelboat race it was time to take the moth out in a decent breeze. The winds were 15-20 and kind of puffy, but I was eager to get out on the water with my new mothing knowledge and see if I could make the more stable on the foils. After cranking on the vang and then cranking it on some more I finely got the boat feeling good. I could go upwind and downwind without much trouble. Then the problems began. After bearing away in a big gust and heading downwind with a lot of pace I did my first high-speed nosedive with a full ejection from the boat. After swimming back to the boat and righting it again I tried to take off, but something was weird. The nose of the boat would launch out of the water but the stern wasn't lifting at all. After a few tries I checked the rudder foil and my suspicions were verified... the rudder foil was completely GONE. Apparently the nosedive had created enough force on the foil to completely strip the attachment bolt from the foil.

I tried to sail back to where I lost the foil knowing that it would float, but finding a black foil in rough water would be an almost impossible. Thankfully my parents where in the area on their Laser 28 and I flagged them down and told them to help me look for the foil. I knew that it was a long shot, but it was worth at least trying. I made a few passes but it was clear that mounting any meaningful search from the moth was almost pointless. Sailing without the benefit of the pitch control from the rudder was hard enough. I sailed dejectedly back to the marina pondering where I was going to get a new rudder foil. As I got back to the docks my parents were just pulling into their slip. I sailed by and my mother reached down and lifted up one fully intact black Bladerider rudder foil plucked from the water just downwind of where I crashed. OMG lucky! Thanks Mom & Dad!

But it turned out this was all very lucky indeed. When I got back to the dock and started pulling the boat from the water I noticed that the spreader attachment had pulled completely free from the mast. So had I not come in I would have risked completely loosing the rig.

So now it’s back to the shop to fix and improve these parts. My only big question now is how to best fix the rudder foil so it can’t come off ever again. The two choices as I see it is to embed a stainless nut into the rudder and then bolt on as before. The second option is to permanently fiberglass the foil onto the rudder. The bolt is nice because I can remove the foil for transport, but at the end of the day maybe the permanent attachment would be more secure and stiffer? What do you think?

Back on the Water

2011-05-15T21:06:00.004-06:00

The 2011 moth season has officially begun with a short but successful trip out onto the water. The boat worked great, the pilot not so much. But I didn't die or get hypothermia so I guess that's a good thing. Plus I got some pics! When I first headed out the wind was about perfect, probably 12kts and steady, good conditions for the first boating of the year. After getting things sorted a bit I headed out again but the wind was starting to come up more. By the time I turned around it was blowing pretty solid 20kts. I now know that I suck at reaching in 20kts. I had a really hard time getting the boat into a grove and I crashed to windward a lot. Thankfully Mothball 1 seems to have a good bow shape for going nose in. For as many times as she went in she never really felt like she was going to go down the mineshaft, even with the bow completely submerged to the mast.

I ended up in this position a lot. I could get up and going no problem and i was trying to keep the boat healed to windward, but I think I'm underestimating how much leverage you get with the boat when you are up on the foils. Clearly there was some wind out there though.

This is the only shot I got of actual foiling. Sorry for the blurry image, but I kind of like it. Its so blurry that its almost artsy. Anyway, the boat is clearly riding high, I could probably use more vang though. Man these sails need a lot of vang. A few rig mods to make now but I think Mothball 1 is going to have a very productive summer.

Bent Wand/Simple Ride Height Adjuster?

2011-05-08T21:08:00.003-06:00

So I built my bent wand, it was quite simple. The main section is made of stiff carbon tube and bottom is a solid small diameter carbon round which is fairly flexible and fits inside the main tube. The lower section is set at about 50 deg off from main tube and has float made from a half section of larger carbon tube. When the boat is flying less than 10 cm above the water it will be controlled by the short main section and above that the 'bent' section will take control. Should work good I think. But I was playing with it and I came up with another cool feature than I could implement. Using the bent wand it would be easy to make a simple ride height adjuster. Simply attach a small diameter line the end of wand and then wrap it over the wand pivot and back to the cockpit. If you tighten this line the wand bends and effectively gets shorter. Simple. Will it work in the real world? I don't see why it wouldn't. Yes the tension on the line will have a small effect on wand pivot, but this effect could easily be compensated by adjusting the wand tensioner. No moving parts, nothing to get jammed, and very little added weight.

The Case for the Bent Wand

2011-04-30T09:07:00.004-06:00

Snowed today. Five inches new on the ground. I'm not sure spring is coming this year. But I'm spending my time thinking about moth sailing anyway and I came up with an interesting idea. I'm not sure its a good idea, but it is an interesting thought problem related to moth sailing. So I need a new wand, no big deal, I have a ton of small carbon sections to build it out of. So what is the ideal wand shape? Most wands are straight, but do they need to be? What if your wand was bent? How would that effect how it senses the water? So here's the thought problem. Lets say you have a slightly longer wand that is bent 45deg about 2/3 of the way down. This would have the immediate effect of making you need to adjust your linkages, but thats pretty easy. When the wand is pointing down I don't think it would change much, except it would change the angle of the end float, which could be nice. But when the wand is up above 45 deg you could end up with some interesting effects. With the wand above 45 deg the knuckle of the wand would hit the water before the float does and would effectively make your wand much shorter when the boat is riding low. I made a diagram of this effect and as far as I can tell the net effect would be a change in gearing of the wand mechanism. When the boat is riding low the wand would sense the water at the knuckle and this would increase the rate of motion of the wand when riding low. When riding high beyond the knuckle the wand would function normally. So would this be a good thing or a bad thing? Effectively you'd get more flap motion when riding low and the same motion when riding high. Adjusting the angle and the location of the bend would create an infinite number of gearing options. You could also put in multiple bends to get different gearing at different ride heights. Has anyone tried this yet?

Thank You USPS

2011-04-17T15:35:00.005-06:00

So after a year of waiting I finely got my official BL daggerboard push rods from the supplier. You may recall that last year I used a push rod made by a local machine shop. That rod worked fine but it was damaged in, um, lets call it an industrial accident. So I got two rods and they showed up in a flat box. As soon as I saw the box I knew something was wrong. The USPS had bent the roads in shipping in several places. Luckily I was able to call the supplier and they agreed that rods probably hadn't been packaged sufficiently to make the trip and are sending replacements. In the meantime moth repair continues, but I fear that the moth is going to be ready before the weather is...

Bulkheads

2011-03-18T08:50:00.001-06:00

To help out the few people who may actually try and build one of these things I’m going to offer up some more design details. One of the cool things about this method of using the stressed and bent plywood hull is that the general shape of the plywood skin pretty much defines the shape of the whole boat. The only real thing that you can change is the width of the deck at different points and how much V you want in the bow. Once the hull is stitched (or taped) together and you can bend it into whatever shape looks good to you. Rather than pre-defining the bulkheads and then forcing the hull to fit that shape, I let the shape of the hull define the shape of the bulkheads. So here’s all you really need to know, the deck width at the mast is 260mm, the deck width at the stern is 355mm, the max deck width is 370mm, and the front of the daggerboard box is 1525 mm from the bow. The V in the deck is 45 mm deep (at the mast). Note that Mothball one is slightly different than what I’m giving you here, but if I were to make it again this is what I’d use. The changes are small but would probably make a better boat.

So if you set those three deck widths it’s time to start making bulkheads. Bulkheads are really pretty easy to make, especially using the same thin ply used for the skin. You can cut out a bulkhead in about 60 sec, but the shape needs to be well defined. Mothball One has 11 bulkheads (including the solid transom bulkhead). Nine bulkheads are in the deck area and two are in the bow. Most of bulkheads have an inverted Y shape cut into them to reduce weight. To define the shape of the bulkheads measure that area on the boat as best you can and then draw the rough bulkhead onto a piece of cardboard making sure to make the bulkhead as square and symmetric as possible. Put the cardboard bulkhead in the boat and then trim it to make it fit as best you can. Then take the cardboard bulkhead and use it as a template to draw the plywood bulkheads. Again make sure the plywood bulkhead is square and symmetric. The skin will define the overall boat shape, but the bulkheads will ensure that the shape is square. If I were to do it again I’d probably add one additional bulkhead near the middle of the boat because that’s where the sides get stepped on a lot after you take a swim. Also note that the bulkhead below the mast should be solid to help create the two separate airtight tanks as defined by the Moth class rules. The daggerboard box has a bulkhead on each end of the box for added strength. Take a look at my older posts for some bulkhead pics.

Design Drawing

2011-03-08T08:42:00.003-07:00

I've had several inquiries about the design for Mothball 1. I have no problem with giving out the design details, but it wasn't in any form that I could easily digitize since it was all on paper. Finely I just decided to take a picture of my large hand drawing and then clean it up with a photo editor. Here's what I came up with. It looks reasonably good I guess. If you want to see how it all goes together just print this out on some card stock, cut it out, fold along the thin red lines and then tape the edges. If anyone wants to take this and make it into a formal CAD drawing, feel free. I'd be happy to answer any questions about the design.

Down For the Season

2010-10-02T21:00:00.002-06:00

Unfortunately the sailing season is Montana is somewhat short, this does make for a good skiing though. Mothball One has been mothballed for the season. The last time I sailed I damaged the main foil again and found a crack the the mast base. Not huge problems, but I didn't have time to fix them and decided to just wait till the spring. The plan is to fix all the problems and have her ready to go when the ice comes off in April. It was a fun year, learned a lot, can't wait fly again, but flying over the snow has its merits too.

Good and Bad

2010-08-08T19:09:00.003-06:00

Yesterday as a very good day for mothing. I finely was able to get the boat in good winds for figuring things out, 10-12 from the south and fairly steady. Everything went very well and I was totally stoked. I recorded 16.4 kts on the GPS for a max speed and sailed for about three hours. I went out again today in hopes of the same but the wind didn't come up at all till late in the day and then it was fairly puffy and shifty. I was working on handling the gusts and the boat was sailing ok, lots of steering errors on my part though, I need to work on that. Then bang! Crap. Look around and it looks like everything is ok but the boat is feeling really strange and won't fly so I look over the side and the daggerboard has split again. Damn. Better do a better job of fixing it I guess.

Little Things

2010-07-30T07:35:00.002-06:00

I'm actually pretty surprised how well Mothball One is holding together. I have had a variety of breakages, buts its all been pretty minor stuff, not the huge splintering carbon fiber carnage I was half expecting to happen. I took the boat out last night for an evening sail in 10tks with some gusts around 20. That was by far the most wind I'd been out in, but she seemed to handle it ok. The boat foils great. Once its up it pretty much stays up till the wind dies or I crash. Unfortunately my sail was cut short by another small breakage. After crashing the boat in a gust I was arranging myself to bring it up and I somehow kicked the wand forward and broke the front rod linkage. Foiling over. It was a stupid little problem and a stupid mistake on my part for breaking it, but the linkage is probably under-built as well. So is the general rule just to stay away from the front of the boat in a capsize to avoid screwing up the wand? I'm also considering adding a rotation limiter on the wand to keep it from being pushed too far forward and stressing the mechanics. Little things, but I hope I can get them all sorted out and really start to learn this boat.

Flying Pics...Finely

2010-07-25T18:18:00.004-06:00

It was a really nice weekend, just not a great weekend for mothing. It was hot and sunny but the winds were 3-5kts pretty much all weekend. Except for a brief period yesterday afternoon it was not possible to foil. But I did a bunch of lowriding practice which is probably a good skill to have. I must say that it is remarkable how much faster the boat is in lowriding mode when you disconnect the wand and reduce that AOA on the rudder. At one point my rudder came off, but I was able to reattach it with a bit of help from a jetski. Luckily I was able to take a few picks of my brother sailing late in the day when the wind picked up to a whopping 7 kts and the boat was just able to get foiling. Clearly the ride height isn't great, but that may have been due to the wind. I did extend the wand a bit today with a plastic spoon handle, but there wasn't enough wind to try it out. This week I hope to make a few modifications to prevent the tramp strings from breaking a keep the rudder from coming off again, but all in all the boat is working great. I can't wait to sail it in more than 10 kts of wind.

FIRE!

2010-07-17T22:06:00.001-06:00

Tried to go sailing again today but the lake is on fire. Freek'n a man!

Design Notes

2010-07-14T20:30:00.005-06:00

I wanted to write a bit about the things that I learned while working on Mothball in the next few posts so I'll start with materials. Woods is a great building material, its cheap and easy to shape and is quite strong. Wood is natural carbon fiber after all. If designed and used correctly its probably nearly as strong as a composite hull and nearly the same weight. So how come no productions boats are made out of wood any more? As far as I can tell its probably mostly to do with how long it takes to build a wooden hull. If you have a mold you can create most of a composite hull in a few hours with great consistency. A good wooden hull takes much longer to build and shape and will have natural inconsistencies. So the money saved in materials cost is lost in the extra fabrication time of a wood hull. If you have a ton of time and don't have a mold then a wood hull makes a lot of sense, but if you were producing hulls commercially a wood hull simply is not practical.

Carbon fiber tubes rock. They are actually really easy to work with. Just cut, bond, reinforce the connections and you're done. Carbon tape is your friend. Kevlar is nice, but is a pain to work with. Its really hard to cut and impossible to sand, well you can sand it but it always leaves hairs. Good old fiberglass is nice for doing finish work because its much easier to sand and finish than carbon.

Resounding Success!

2010-07-10T15:15:00.002-06:00

Today was the first real day of sailing on Mothball 1 and I must say that it was a resounding success. After a marathon repair session yesterday we fixed all the broken parts and reassembled everything early this morning. My brother had to leave early so I let him go out first. I tried to follow on his keel boat but the motor crapped out so I couldn't take any pictures. He came back in and was surprised that the boat had taken off and foiled instantly. I was surprised too. He needed to leave so I went out on the boat and spent the next two hours on the water foiling most of the time in a nice 8-10 kt breeze. The boat feels great. Surprising good actually. The wand response is good, the rudder foil adjusts well and trimming the boat is easy, the rudder is surprisingly balanced, the rig works fine, and the only thing that broke is was one tramp string. I even tried to pull off a foiling jibe, it failed miserably but whatever. I was expecting to have major mods to do after the first real sail, but all I really have to do is inspect everything to look for problems areas and do some refinement on some of the systems.

First Flight

2010-07-09T17:26:00.002-06:00

Mothball 1 has officially had her first flight, it was somewhat brief, but she did fly. I got everything rigged up this morning and hit the water early, the wind was pretty light on the first run and I broke some of the lines on the tramps so I went back in to fit it. When I went back out the wind was up a bit and I could tell she really wanted to fly. The rudder wasn't giving quite enough lift so I had to move way forward to get the boat out of the water but she finely took off and flew for about 10 sec until I ran out of lake. I tacked and headed back the other way and she took off again and really started moving. Everything went quiet and the rudder got really sensitive but she was off and she felt good! Then POW! The sound we all hate to hear. The boat crashed back to the water relatively smoothly and I kept sailing trying to figure out what had broken. The foils were still on, the rig was up, everything was in its place, but she clearly wasn't interested in going onto the foils any more. A brief inspection at the dock revealed the problem, the daggerboard had separated down the middle. Apparently I hadn't bonded the two sides together well enough and it just cracked. Luckily there wasn't any major damage. Spent the last four hours re-bonding the sections and its back out to the lake tonight. I'm kind of amazed this thing actually flew without making any major adjustments on the first day! Yay!

Moth Lube?

2010-07-07T13:12:00.003-06:00

The SS rod is done. All thats left to do attach the rotating pin in the flap and do final adjustments. Friday will be the day for the test flight. Yay. One quick question, is there a recommended lube for all of these moving part?. Everything on the boat is reasonably low friction, but I figure lube is always good. What do people generally use for lubing the push-rods and such?

Foiled Again!

2010-07-02T07:13:00.004-06:00

For a variety of reasons, my goal of foiling this weekend will not be accomplished :( There are several reasons for this, not the least of which is the fact that the guys at the machine shop did not come through with the parts, but its also the July 4th weekend, my daughters birthday, company is coming, bla bla bla, so maybe this is best anyway. The good part here is that instead of rushing the last few jobs and then splashing the boat I should be able to do a bit more refinement over the next week and I promise next Friday will be the day. I even ordered some additional fiberglass rods yesterday to ensure that I will have a functioning push-rod available by the end of next week. The glass rods may not be as good as a stainless ones, but it should be good enough to last a day of beginner mothing if needed.

But speaking of foils, check out the mostly finished products. They still need a small amount of fairing and need to be pained, but should be quite functional and honestly look quite nice. I added the bullet on the main strut at the last minute, but it turned out really good and should help make the joint stronger. The thing seems pretty stout, I didn't test it to destruction but I pulled on the ends pretty hard and it gave no sign of even flexing. Do note that the rudder seems to be slightly longer than the daggerboard, this was just a function of how they got assembled. Once installed on the boat the foils will be pretty much in line going through the water. The rudder foil is currently screwed on so I can change the length if necessary. Does anyone have an opinion on having the rudder slightly longer or shorter than the daggerboard?

OMG Close!

2010-06-29T21:02:00.002-06:00

The machine shop claims that the push rod will be done tomorrow. Yay. Today I finely broke down and created a test push rod and crank connector. The connector was plastic and the rod was taped together in the middle, but it sort of worked and let me align all of the components and then bog the sides of the board together. Tomorrow morning I attach the horizontal, do some reinforcement and some finish work, go and pick up the push rod (fingers crossed), and get ready to splash this thing!

Bladerider Copy?

2010-06-26T20:25:00.003-06:00

So I started thinking about Mothball 1 and I realized that this thing is pretty much a Bladerider. I wasn't intending to do this but it just kind of turned out that way. I got all the parts randomly over several year but they all ended up being bladerider bits. Maybe this is just because that's all that was really available. Sail - Bladerider X8, mast and boom - C-Tech, rudder horizontal- Bladerider, Mechanical bits- Bladerider, the boat geometry is similar to the Bladerider, the total weight is almost the same, the only big difference will be in the main lifting foil. Will it perform like a Bladerider? Probably not, but it should be close.

Waiting isn't all bad

2010-06-21T06:51:00.003-06:00

The good thing about being forced to slow down on a build is that it gives you more time to test things before they get put to use. When I assembled the boat I jumped all over on the tramps and the small carbon connector rods I was using started to explode. They were clearly not up to the task. Not hard to fix, but I was glad to have broken them on the hard rather than the first time on the water. I also decided to change my wand geometry slightly to reduce friction and eliminated some play in my rudder adjuster. All of these things should make the first voyage go much better.

The Finish is Near

2010-06-18T18:18:00.003-06:00

Spent most of the day doing misc. finish work on the boat. This thing is nearly done. I have a variety of small items left to finish, but it could be operational in a matter of hours... if it weren't for the FREEKING daggerboard. Sigh. The daggerboard is still in many parts with a few critical components missing, namely a 2mm push rod. I'm doing my best to get one made and I have another on backorder, but still no luck. I don't want to assemble the daggerboard without it, cuz if something doesn't work when I insert the rod, I'm totally screwed. So instead I'm waiting and waiting and waiting...

Pressure Testing

2010-06-13T20:49:00.002-06:00

Leaky boats are bad, but how do you know your boat leaks before you put it in the water? Simple, a bike pump, soap, and water. You plug the bike pump into the hull and then use the soap and water to test suspect areas. If the suds blow bubbles, its a leak. Using this method I think I found at least most of the small leaks. It won't hold the pressure from the bike pump forever, buts it clear that Mothball is fairly watertight. I was also able to get the rig up with the sail on to begin testing on the running rigging. The goal is to splash on Friday. Wish me luck.

Supertramp!

2010-06-01T21:34:00.002-06:00

They really are super, nice fit, a bit of finish work still, but clearly functional. A big thanks to my dad for helping design and sew them.

Almost There

2010-05-31T18:30:00.003-06:00

Did a lot of work on the boat this weekend and I'm happy to say that its getting pretty close to done. This weekend I sewed the tramps, faired the hull, got the rudder adjuster up and running, made progress on the rudder gantry, and started the daggerboard box. There is some finish work to be done on all of this stuff, but I'm happy with where everything is. The only outstanding item is that I still do not have the 2mm push rod for the daggerboard flap. I may end up needing to build one, but that wouldn't be too tough. I'll work on getting some pictures up tomorrow.

28 lbs

2010-05-24T10:27:00.003-06:00

Weight is everything on the moth. Heavy things don't fly. I've been trying to get a handle on the boat weight for a while but frankly I couldn't find a good way to accurately measure it, until today. With the aid of a few pulleys and some weights I was able to suspend the boat and check the hull weight. It turns out the total weight of the mostly finished hull is 28 lbs. I still need to do a bit of fairing and paint it, but 28 lbs is actually quite good for a home-built plywood hull. It is about 10 lbs heavier than the Mach 2 (~18 lb), but its significantly lighter than the Bladerider FX (~40 lb). This thing may actually fly.

Getting Closer

2010-05-10T15:12:00.003-06:00

So I have been slowly progressing on this thing, but running a business, taking care of a two-year old, getting a keel boat ready to race, planning a national regatta, and building a Moth takes a lot of time. I'm not complaining, its all fun, its just hard to focus on one thing. Anyway, here's were we are. I have almost all of the parts finished for the rudder and tiller assembly. The rig is pretty much done. The hull is mostly done but needs to be faired a bit and painted. I'm waiting on some parts so that I can finish the daggerboard and main foil and I need to sew the tramps. I also need to get the misc. hardware and get everything mounted on the boat. And I need to build a dolly. It's really just a lot of little stuff at this point and I'm still hoping to be sailing in a month, but tomorrow its off to Seattle for the NOODs!

Holy Epoxy Batman

2010-03-06T16:06:00.002-07:00

So here is the Bladerider foil that I'm fixing up. I drilled two small holes in the foil where the core was crushed and started dripping in epoxy. And OMG did the epoxy flow. I had to go back to the garage three times to get more epoxy. It took twice as much epoxy as I was expecting to fill in the void. It seems to have done good job though.

Foils, foils, foils

2010-03-05T19:30:00.003-07:00

The foils are all here. They all need some work, but at least they are here. Lets start with the rudder horizontal. This is a nice Bladerider foil that got into "an incident with a power boat". The tip of the foil got cracked and the foil is scratched up quite a bit. Originally I was going to just put some extra carbon on and call it good, but now I have a better idea. The damaged area was very compressible and seemed like the core must have been totally crushed. So instead of reinforcing the outside I'm going to drill into the the foil and then inject epoxy in to replace the core. Then with a bit of fairing and some paint it should be good as new.

The rest of the foils will take a bit more work. They should turn out great, but they are less than completed. The foils are in two halves at the moment. The main foil and the rudder foil came out of the same mold, the only difference being that the main foil is constructed with more carbon than the rudder. I'm going to try and fit the rudder foil into the Bladerider socket. All I should need to do is shape the end and fit a bolt into it then attach the two halves.

The main foil will be a bit more involved. The main foil need have a bunch of mechanical bits fit inside of the foil. At this point I'm not even really sure how to make this happen. Better call Gui.

More Progress

2010-02-16T19:23:00.002-07:00

So there isn't much new as far as assembly goes, but lots of new on the parts front. New just today, FOILS! Holy crap Batman. I can hardly believe that I actually got foils, and I didn't even need to spend a fortune to get them. Granted they are not totally finished and will take a bit of work get them ready for the boat, but they look really good and should work great. I was talking to fellow moth home-builder Gui and he had a set of unfinished foils that he didn't need. He's a great guy and ended up selling them to me for just the cost of materials. However, he didn't have a rudder horizontal foil so I needed to find one of those. I send out a message on the US Moth groups page and found a slightly damaged bladerider foil that I was able to purchases very inexpensively. I also purchased some kite tubes to use for some the control rods. As soon as it warms up a bit things should start coming together fairly quickly.

Deck Reenforcement

2009-11-20T19:14:00.003-07:00

I love Sailing Anarchy. If it wasn't for that site I would never have attempted this project, but SA is a place you can go and get answers for ANY question. This time it was the deck. I didn't want to leave the deck as just 1/8 ply, it just wouldn't have stood up to abuse. So a quick question on SA gave me the answer. The deck now has a layer of carbon and kevlar underneath which should make the deck quite strong while adding minimal weight. By the recommendations of SA, the kevlar runs the length of the boat and the carbon runs the width. Is the boat now bulletproof? probably not, but I'm at least not going to put my knee through it.

I also got the mast bases turned last week. They look good, but I think that material I got (2" dia delrin) was about 1/8" too small in diameter. I don't like the amount of lip I have holding the base of the mast. The last thing I want is to get it base jammed into the mast and end up cracking it. I'll probably get some more material and turn some new ones in the spring, but at the moment this will work.

Proof of Life!

2009-10-18T18:31:00.002-06:00

It lives! (or at least the parts can be assembled)

Mast Attachments

2009-10-17T06:46:00.002-06:00

There are things sticking to the mast. Yay! If I'm in the mood I may try and get the mast up this weekend to start looking at everything and take some pictures. The test spreaders are constructed (amazing what you can do with a jig saw in an hour). This thing is really starting to look like a boat. Now if I only had foils....

Current Build Status

2009-10-12T13:00:00.003-06:00

Ok, so after my long delay in progress I'm getting working again and things are moving right along. I'm actually pretty surprised at how fast things are going at the moment, but with the hull and racks mostly completed, much of the rest is the small detail work which is fairly easy In the last week I have in installed the compression struts to the mast post and am currently working on the rigging. The components of the rig are as follows:

Mast Base
Boom
Spreaders
Shrouds

Having completely blank tubes from which to build all of this stuff has given me a lot of freedom about how to put it all together. Lets start with the mast base. This part is pretty easy. Its two chunks of delrin that are cut to fit in the mast post and the bottom of the mast with a cut-off bolt head to act as a pin. The hardest part about this was finding the delrin, which I ended up getting off of E-bay. I will have the delrin lathed to fit the two end.

Boom - pretty easy really. Just cut the end of the boom to fit around the mast and then attach it with a bolt. I also have the hardware pieces for the vang and outhaul on order.

Spreaders - I spent some time with some scale drawings trying to figure out the perfect geometry for the spreaders. I think I'm pretty close, but I'm going to build a set of test spreaders that will have a variable geometry so that I can test them a bit before I build the real set.

The mast attachments will be made of solid carbon and are pretty close to being ready to put on the mast. Once these few things are done I should be ready to put the rig up and start testing it out. Once I get everything how I like it there will be some finish work to do, but I have all winter to do that.

Progress, OMG!

2009-10-04T17:22:00.002-06:00

Wow, has it been a year since I've posted? I guess it has. After dealing with a bunch of happy horse $hit over the last year, work on Mothball one has resumed. I'd almost forgotten where I was, but now that I'm going again I remember how much fun this project really is. Hopefully over the next month or so I'll get a lot of stuff done and have the boat ready to go in the spring. More updates to come soon.

Hey, it looks like a Moth!

2008-10-09T18:18:00.003-06:00

This thing is actually starting to come together. The racks are assembled and most of the hull is done. I need to re-inforce the deck with a carbon/kevlar fabric and do some extra finish work inside the hull, but its just about ready close up. After that I need to finish the mast support and then tape the outside joints and it will be time to think about fairing and painting the hull. I'll probably wait a while to do that though.

Some fun notes about racks, building them off of the boat is the ONLY way to keep them square and I think I did a pretty good job. It is a little scary putting everything together on the floor and then hoping that if fits on the boat. To this end I didn't reinforce the angle in the carbon tubes until I checked that it was all going to work. This was probably a good plan, but it also lead to several joint failures while moving things around. They were easy to fix, but it was a bit un-nearving. Another note, the rack frames are quite large when assembled. The frame is close to seven feet square. Once its on the boat its fine, but its really hard to pick the entire frame up just because you can't reach very much of it at a time. I am really glad that I made the frames collapsible.

Racks!

2008-09-28T15:57:00.002-06:00

The racks are coming together. This is somewhat of a slow process with lots of little pieces needing to go together in a particular order. The racks will be removable from the boat and will be collapsible for storage/transport.

A few things I learned so far about racks. They are not easy to put together. First they need to fit on the boat, and they also need to be square, and they need to be solid. My method for attaching them to boat should work fairly well. First I made the crossbeams and attached them to the boat where I wanted them to be. However, its really hard to make them square on the boat, so I needed to remove them from the boat to square everything up. Then it will be back to the boat to re-attached them. It sounds a bit weird, but I really couldn't think of another way to do it. I'll post some pics once all the parts are attached.

The racks are solid carbon and should be really tough once I get done with them. Strangely I had to purchase almost no carbon tubes for this project. Some people have random 2x4s in their garage, I have random lengths of carbon. I purchased the big tubes years ago with the idea of putting racks on my I-14, never got around to it. The cross tubes I purchased for almost nothing a long time ago, just because they were a good deal. I used a few of these tubes over the years and had just enough left for this project.

One more note of interest. I don't intend to attach the racks pieces in any permanent way. The big bars will have stubs which will slide into the cross beams. Then everything will be held together by the tramps. I'm going to use a few tricks to keep the parts from rotating or moving at all. Hopefully it will be really solid.

Interior Structure

2008-08-26T21:26:00.005-06:00

Here is the interior of the boat. There is a bit more work to do here, but its getting pretty close to done. Once the interior is done all I need to do is put the deck on. I could do that pretty soon, but I'll probably leave it off till I get more parts finished, cuz once its on, there is no opening it up again.

In the middle of the boat you'll see the daggerboard box. The box is made out of plywood with a layer of carbon inside of the box for added strength. Note the tabs along the end of the box (they are covered with a bit epoxy). I made the box with these tabs on both side so that the box could be assembled with precision inside the boat and then bogged in place. As anyone who's worked with epoxy knows, lining up parts can be tough when gluing multple pieces together. The tabs on the box were aligned precisely so that it could only fit together one way.

You'll also notice that the box is slightly larger than it needs to be. Infact its 1" x 8" which is much larger than any modern daggerboard. But since I don't have the foils yet I made the box larger than necessary so that I can finish the boat without having my foils and know that I can make anything fit. Once I get the foils I'll make and insert for the box that will exactly fit the foils. This way I can also change foils in the future without much trouble.

The 11'3'' Moth

2008-08-26T21:14:00.006-06:00

Here is the bow of mothball1. How did the end get blunted so well? Originally the boat was 11'3'' by design, even though the hull can only be 11' 0'' by class rules. In order to keep the lines constant I made the boat slightly longer and then inserted a shaped piece of wood at 11' exactly and then cut the last three inches of the hull off. This will make a very tough and nicely rounded nose without changing the lines of the boat. I think it looks pretty good. a sharper nose may be slightly faster, but its also more vulnerable and decreases the volume in the front of the boat. One of the realities of the hydrofoil boat is that maximizing displacement mode boat speed is silly. Once you start to exceed hullspeed you will by on the foils so it doesn't really matter how fast you can go while lowriding. Its better to make the hull more functional for lower speeds than maximizing displacement boatspeed.

Home Sweet Home

2008-08-04T13:59:00.002-06:00

This was a good weekend for Mothball1. Not only do we have some of the internal bulkhead bogged in place and the deck shaped, but I also transported the boat back to my house. The ride home was a bit more eventful than I was hoping. About ten minutes after we left with the boat on top of the car we drove through a fairly large rain and hail storm. There was nothing we could do about it so we just kept driving hoping it wouldn't damage the raw wood on the hull too much. After we stopped I inspected the boat and found no hail or water damage at all. Yay!

Having the boat at home should speed up the construction process considerably. There is still lots to do, but with the boat in the garage I should be able to spend a lot more time working on it. I spent a bit of time sanding on the bottom of the hull and it turns out that the major screw-up that I did at the beginning of the project isn't going to take that much to fix. A bit of sanding and some filler should fix most of the problem areas. The boat should begin looking very Mothish over the next few weeks.

Parts is Parts

2008-07-25T18:10:00.002-06:00

It's been a while so I suppose it's time for an update. Not much progress on Mothball over the last month, but we now have lots of parts, so thats cool. The lack of progress has been due to good things though, like vacations, sailing, racing boats, selling sailboats, family stuff, and other random summer stuff. The Mothball has not been the top priority. But now we have cool new stuff. My C-Tech carbon mast and boom arrived last week and I recently got a used Ka X8 sail for a good price. I now have all of the tubes and materials needed to build the boat. I'm still looking for options for foils, but I'm not to the point that I need them yet. I still need to pick up parts for the foil control system. With some luck the Mothball will be transfered to a new home next weekend and then the detailed construction can begin. Don't know if I'll hit the water with it this year, but I'm really not in a huge hurry. Then again, the Moth Worlds are set for next year at the Gorge. I can be there in just 10 hours from my house. It would be cool to make that happen, but I'm going to need to be ready to go next spring and be practiced enough to make a reasonable showing. I better get on that.

I see your Schwartz is as big as mine!

2008-06-04T14:41:00.004-06:00

Thanks everybody for the replies. It really did help give me some direction with this one and I think I've come up with a good solution. I am going to forge ahead with this hull. No matter what it will be a great test platform and I will certainly get it on the water sooner this way. My goals for the project are going to change a bit though. Instead of trying to make a great boat on the first shot I'm going to try and make a functional boat and learn as much as I can without spending too much time and money on this hull. This should let me cut a few corners and get onto the water much sooner.

Carbon skin - GONE
Internal carbon reinforcement - GONE
Perfect smooth finish - GONE

This will be a total test hull for learning the building techniques and getting the overall shape right. I intend it to be very underbuilt and expect it to last only one season. I better include some major buoyancy bags though. Plus, without any carbon skin of any kind, Mothball One MK 1 will be a super fast flying woody! Ahh, Mel Brooks would be proud.

Also, got my sail from the UPS guy today. A used Bladerider 8x thats in very nice shape. Thanks Bora!

Day 1- Part 1

2008-06-02T15:58:00.005-06:00

The Mothball One project started this weekend and all in all it went pretty well, to a point. We learned a lot and had some great successes. But now I’m at a decision point. Keep reading and give me some direction as to what I should do next.

Step One- Cut and Connect the Plywood

We did this using a puzzle joint and it worked great. It took a bit of time to cut out the puzzle ends, but the finished product was fantastic. Totally smooth and very tough. Well worth the effort. This won’t ever come apart.

I would totally do the puzzle joint this again, but there was one small problem with it. You need a big solid flat place to lay the plywood on to let the joint cure. The best choice for this was the garage floor. The only issue was that the garage floor is cement and it was pretty cold, which massively extended the cure time of the epoxy. Not a huge deal, but it did mess up the construction schedule. We put the joint together at 9:00 AM and weren’t able to start working with the wood till almost 2:00, even with a heat tent. This is not a huge deal, but I would have preferred to have started the day before with this and let it set overnight.

Step Two- The Plans

After the epoxy cured I was able to draw on the plans for the hull. This was done by overlaying the paper plans and then punching holes through the paper into the wood and then connecting the dots. Went quite well actually.

Step Three- Cut it out

Cut along the lines using a jigsaw. Easy, good results. You also need to groove the plywood where you intend to fold it. I used a circular saw set so the blade only cut 1.5 mm of wood. Also filleted some of the joints so they would come together better.

Here was a good trick. Use clamps to connect the wood together with some scrap pieces when moving or flipping the wood. This helps prevent breaking the ply. We also attached some stiffening rails to the edges. These were attached with epoxy and screws which would be taken out later. We were done with this step by 5:00

Step Four- Form the Boat

Started again after dinner and began to form the boat. This was done using some water and my mom’s clothes iron (shhh, don’t tell). It went exactly as planned. It took about an hour to go from a flat piece of wood to a nice boat shape. Check it. Only 14 pounds at this point. Right where I wanted to be.

Step Five- Connect the Joints with Carbon Tape

Easy. Just apply epoxy to the wood, lay in the tape and smooth with your gloved fingers. It’s now10:00 P.M.

Now Walk Away.

Damit, I said walk away.

You just couldn’t walk away could you.

So here is where things got a bit weird. In an effort to flatten the bottom a bit before the carbon cured I put some weights in the boat help make the correct bottom shape and then went to bed. When we got up the next morning things had changed, for the worse. Over the night the weight in the boat had slowly collapsed the V bottom under the support. This looked very bad. Luckily the epoxy hadn’t totally cured and with a bit of extra tape and some heat we were able to bring it back into shape. Mostly. With a bit of fairing I could probably make it perfect again.

But now I’m at a junction. The project has actually gone quite well so far except for the one major screw up on my part and we have learned a lot. But there are already some things I would change and I need to decide if I want to just keep going with this hull or start over again and make the changes before I invest any more time and effort into this boat. At this point I only have one day, 1.5 sheets of plywood and 30ft of carbon tape invested.

What would I change? Well not that much, but it may be significant in the long run. First I’d change bottom profile of the boat. It’s not bad, but the transition from the V bottom to the flat bottom is not as good as I’d like. I’d also maybe make the bottom a bit flatter. Secondly I’d let the hull flair wider when I tape in the first joints. This is supposed to be stressed plywood and it didn’t take much stress to get it into the final shape at the end. The added stress would make the whole hull stiffer. I’d also make the stiffening rails a bit smaller to reduce weight and use some supports on the stern to keep the ply from bending too much initially. These problems combined with my screw up on hull make me want to start over completely, but it’s not that bad and I could certainly salvage what I have now and make a functioning boat.

What do YOU think? Leave a comment.

How Do You Build It?

2008-05-25T21:48:00.004-06:00

So how do you build a moth? Well, there are lots of ways, some easier than others. My goal was to use a construction technique that would be simple and cheap and yet relatively tough and light. I really like Phil S’s technique using tortured marine plywood. But my design not only called for torturing plywood, but also creasing it. So how do you fold plywood? I wasn’t sure, but I had some ideas. These ideas needed to be tested before I finalized my design. I got several 2’x2’ sheets of 3mm Okoume marine plywood and began to test folding techniques. After just a few tries I found that plywood can be folded pretty easily. Here’s what you need to do, first you need to groove the plywood where you want it to fold and remove enough material from the back side of the fold so that it does not bind upon folding (about 60% of the 3mm ply for a 90deg bend) Then you wet the wood and heat it with a hot iron. After you do this you will find that it folds pretty easily. Let dry and then glue on place. Done. First obstacle down.

After working on the folding technique I went ahead and build a 1:8 scale model of the boat with the 3mm ply. Turned out pretty good I think. I was also able to use this model to estimate the weight of the basic hull (no internal frames or deck). 13lb. Not bad. Granted I still need to add a lot of stuff and the final hull weight will probably be +2x that weight, but it’s an ok start.

While plywood construction is pretty effective for a job like this, it will not be as light as a fully vacuum bagged carbon foam construction. Also, the raw plywood is not great on durability so I intend to give it a single layer carbon skin over the hull on the outside only. This will present some construction challenges and add some weight, but it’s probably worth it to make a boat that will last.

Next Time – Parts and Pieces

The Design

2008-05-24T15:23:00.006-06:00

The hull on the modern Moth does very little. Unless the wind is low, the hull is totally out of the water. So other than aerodynamics and weight, the hull has very little impact on sailing. For this reason, you don’t need to have a highly specialized and evolved hull design. There are some important design considerations and you do spend some time with the hull in the water, but for the most part you can have whatever shape hull you want.

My hull design was based off of Phil S’s plywood moth desi gn. The overall structure of the boat was reduced considerably from Phil’s designs to more closely resemble the newest generation of boats. I also wanted to put some pretty hard chines on the hull. Although a round hull is faster going through the water, a flatter hull with hard chines will plane faster and theoretically fly sooner.

Here are some pictures of the iterations of hulls shapes I created using cardboard. I tweaked each hull generation slightly until I got a hull that looked how I wanted it. I think the final result looks pretty good. After I completed my final design I discovered Doug Culnane’s moth Blog. Doug has been building moths for years and seems to know what he’s doing. His blog was nice enough to provide measurements at key points all over his newest boat. I started looking at these measurements and checking how close I was with my design. The verdict: close, really close, scary close, I-promise-I-did-not-copy-your-boat-design-Doug close. The reality is that Doug and I chose to do somewhat of a similar construction technique and that technique really lends itself to this boat shape. At least that’s the story I’m going with.

The only real difference the Mothball One will have from other modern designs will be the knuckle bow. This is a modification that I came up with which should have some good effects on sailing. The idea came from the latest generation of America’s Cup boats. If this design is used on the ultimate seahugger boats, then it should hopefully have some good effects on moth sailing when in seahugging mode, in theory. Also, it should improve the touchdown handling of the boat. The knuckle bow should impact the water all at once which will hopefully reduce the water entry speed and lessen the nose dive tendency... in theory.

Next Time – Construction Technique.

So Why a Moth?

2008-05-24T14:34:00.003-06:00

Cuz they’re cool, that’s why!

But I suppose there is a bit more too it than that. I have never sailed a moth. But I have been sailing since forever and did a lot of windsurfing when I was younger. I purchased my first real boat in 1999, a penultimate International 14. It took me years to really get a handle on how to sail a high performance boat. I sailed the I14 at the Worlds in Long Beach in 2006 and had a blast. We did fairly well considering we had the oldest boat in the fleet and were not up the current rules standards.

In 2007 we had a little baby girl Megan. She is probably the cutest little girl ever, but it became really clear that Megan was not going to be sailing an I14 for a very long time. We also have a SanJuan 21 for a family/class racing boat, so the I14 sailing became pretty questionable and the concept of having a small one person super-high performance boat became really appealing. The Moth was the natural fit.

So why build a moth. Well, several reasons. First, cuz it’s going to be way cheaper than buying one. Secondly, cuz I can. I’ve done a lot of work with epoxy and carbon over the years and my background as a civil engineer gives me a pretty good handle on the structural part. Also, I have collected several sets of random carbon tubes which are the exact right sizes to build the racks, for a savings of $1000 or more. Building a boat from nothing is pretty appealing to me. It should be a great learning experience and is great for your sailing cred.

Next time, the design.

Step One

2008-05-23T18:01:00.000-06:00

In compliance with Section 12.4a of IMCA rules, this is the official blog of Mothball One, the Montana Moth Project, Bobzilla vs. Mothra. This blog will be the full account of the construction of the International Foiling Moth, Mothball One.

Here are some links of Interest.

The US Moth Website

Spaceball One!

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