Dude, where’s my stump?

 I was planning to show you guys the photos of all the cool improvements I’ve made this year.  Ride-height adjustor, new gantry, stuff like that, but now I have a new moth chronicle to relate.  I went out sailing early this morning because the forecast was 10-15 diminishing by noon.  I rigged up the boat and it looked like it was starting to blow pretty good on the water.  I was ready to try and get some good numbers on the GPS.  I headed out and started sailing downwind.  The wind was a bit puffy and I instantly was sailing 15-18 kts with good control.  As I made it down the lake farther the wind started to pick up more.  I sailed down the lake for about a mile and then came back up to meet some family members who where sailing my way on keelboat.   I pasted them going upwind and then bore away again in a big puff.  This one was really strong.  The GPS log put me at 20+ knots for over 60 seconds with a max speed of 23 kts, my new personal best.  The boat handled fairly good but I decided to work my way back upwind in the big breeze.  Upwind was pretty hard, by now it was blowing 25-30 steady and I was having a hard time getting the boat going into the stiff breeze.  I sailed back to the marina and took a break hoping the wind would settle a bit.  About an hour later I headed back out.  The breeze was down a bit, but pretty steady around 20 with some good waves.  I was sailing downwind at about 18 kts and stuffed the bow into a wave, it didn’t seem like a bad impact but the terrible crunching sound told a different story.   The boat flipped over and I instantly knew something was very wrong.  I righted the boat but the rig was clearly down.  Looking forward the reason became instantly clear.  The mast stump was completely gone, just a jagged hole remained in the top of the boat.  The rack struts just hung in space.  I wasn’t too far from shore and the wind was blowing me that way so I wasn’t too worried about being stuck in the lake.  I swam the boat toward shore and watched helplessly as the mast which was now bouncing in the waves on the unsupported racks breaking the joints.  It took some effort to keep the gaping hole on the top of the boat from taking on water and filling the forward tank.  Finely I got to shore and started taking the boat apart.  Shortly after my family came along looking for me and we stacked all the broken parts on the deck and started back to the marina.

After taking everything apart and looking at the broken bits I’m happy to say that Mothball 1 will sail again, but not this season.  The racks should be easy to fix and there wasn’t much other damage.  Thankfully I didn’t lose anything.  The remains of the mast stump were held to the boat by a small guide and the tiny line for the ride-height adjustor.  The stump had failed by compressing forward into the deck.  I should be able rebuild it and reinforce the area to take the massive loads that I’m starting to put on the boat.   All in all it was a good day.  I’m just glad I didn’t get hurt or sink, but mothing season 2012 is now over :(

Time for an Upate

Where has MB1 been this summer?  Well sailing actually.  So far this year I've logged over 100 miles on the foils.  The boat is working great and I'm starting to feel pretty confortable at the helm.  My tacks and jibes still have a long way to go, but I'm pretty sure that I could race the boat now and not make a fool of myself.  I'll post some more info about the mods I've made this year over the next few days. 

As a moth sailor all I can say about the flying AC72s is Fuc$ Ya!

Stainless, Brass, or Carbon?

I’m in the process of building a new gantry out of carbon.  It looks really good (pics soon), but I’m planning on upgrading my rudder pin in the process.  Right now I’m using a ¼” stainless pin which has worked fairly well, but I’ve bent it several times so I don’t think it’s really up to the task.  For a replacement my choices are 5/16” stainless, brass, or carbon rod.  Stainless is the most obvious choice but it seems like brass may work just as well and is far easier to work with. My other choice is a solid carbon rod which would be way lighter than the metal rods but I’m not sure if it would be up to the task.  Carbon would also be able to flex without bending and could shear off without damaging the rudder.  Any advice?

Space Moth

I was looking at Google Earth yesterday and realized that the satelite photo of my area had been updated.  It was clearly a summer photo and the lake was busy so it must have been taken on a weekend.  After a bit of searching I found Mothball 1, unfortunately I wasn't sailing.  The boat was under its cover in the rigging area, so I must have been getting ready to sail.  Can you find Mothball 1?

Upward Force

I have a new question for all you Mothies out there. How much force does it take to hold the daggerboard down while sailing? I’d think that there must be quite a bit of force upward on the daggerboard while sailing between the weight of the boat crew and acceleration forces. The reason I’m asking this is because I need to re-design my daggerboard box to work with my ride height adjuster. The daggerboard box on Mothball 1 is a 1”x 8” rectangular reinforced box that has a tight insert that bolts into the daggerboard box at the top to kept the foil from raising above the deck level. Then I had a pin that mostly kept the daggerboard from falling out while sailing. However, I need to change some of these parts to make the ride-height adjuster work and that includes cutting off parts of the daggerboard box insert and many of the areas that bolt the insert to the boat. Clearly I need a major re-design here. So the questions remains, what’s the best way to hold the daggerboard down? The two best options I see are to simply beef up where the pin goes through the daggerboard and assume that it will hold up. But my other idea is a bit different and seems like it would be much stronger. The other ideas is to bolt a removable flare onto the daggerboard at the bottom of the hull, so instead of holding the daggerboard down from the top with a pin, the flare would push up on the bottom of the daggerboard box in an inset receiver and prevent the foil from moving, then I’d just pin it on the top again to keep it from falling out. I kind of like the flare idea because I could make the foil/hull interface much stronger and stiffer utilizing the beefy rectangular daggerboard box originally designed in the boat. How do other boats deal with this?

Boat-Work Season

It’s still a bit cold to begin sailing in Montana, but ski season is officially over so let boat-work season begin! Thankfully most of my projects this year will be easy, I want to re-finish pretty much everything and make a few mods/improvements, but nothing too drastic. One of my projects for this year will be to construct a new rudder gantry. I must say that the original gantry that I fabricated out of solid oak was probably the strongest thing on the entire boat. After two years of useit never had a single failure, but that’s probably because it weighs a ton. Going to a carbon gantry will save me a lot of weight. So now I’m trying to figure out what diameter and wall thickness I need in a carbon tube to give me good weight savings but still be reliable. Is there a standard recommended size for gantry tubes?