2012 Projects

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

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

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!

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

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 ?

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 ?

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

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)

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

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

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

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

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

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?

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

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

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

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

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.