Upgrading My SC20

[Kevin Keller]

I have worked with Tom over the last year or so to upgrade my boat to be similar to a ARC-22. I changed out the beams for one piece beams, installed a current Aquarius trampoline, self-tacking jib, and a boom-less mainsail. It has helped to have machine tools below my house to do a lot of the machining.

I started by picking up new beams in California, 12 foot long X 4 inch X 1/8 inch thickness. After anodizing in California I got them home and machined the dolphin striker post hole and the locating holes for the saddle pins. There is a 5 degree rake which I had to take into account. The hardest part was getting the new dolphin strap mount holes in the correct position. For every inch you move the end strap mounts you change the depth of the striker by 10. Needless to say I screwed it up but was able to move them and have a nice backing plate inside the beam so that they don't move. I got someone to weld in the striker bushing.

After getting that finished I put a 1/4" by 1/2" piece of aluminum bar inside of the rear beam and drilled holes to mount the solid traveler track. I used a transfer punch to locate the holes exactly, drilled through with the correct tap drill and pulled out the bar. I tapped the bar, enlarged the holes in the beam, reinstalled the bar, and then screwed in the track. Since the beam is 4" diameter I used a 4 1/2" piece of ABS pipe to get the port end of the beams to fit in the 4 1/2 saddle. I cut the ABS on one side lengthwise to get it on to the beam and allow the beam to be compressed.

Tom designed a tramp for me since I don't have a track in the aluminum beams for the tramp to slide in like the new boats. I mounted the beams and marked where the tramp grommet holes were located. Then I drilled and tapped holes for the eye-straps I used. I mounted the tramp and was very happy to see how nice it looked. The only thing missing was the beer holders that my previous tramp had. Incidentally I will be selling my old tramp.

Next I had to fit the compression pole. Tom designed some new sails for me and had them made. I put up the jib and found that the pelican striker pole was not long enough for the dimensions of my boat. Instead of shortening the bridal stays to bring it lower and putting more stress on my hulls I cut the pelican striker and lengthened it by 8 inches. When I mounted the jib it looked very nice.

The self-tacking jib track then had to be mounted. It has a compound curve and is mounted on a carbon fiber base. I centered the track with a screw and then located the base below it, drilled and tapped the mounting holes.

I replaced my SS stays with Dynex Dux synthetic line. I also replaced the trap lines with Amsteel. I do like the synthetic lines. It is easy to work with and splice. The only problem I have had so far is the stopper knots in the Amsteel lines I use to adjust the stay length with, unless they are pulled really tight tend to slip a little until they set. They really look nice and probably hurt a lot less when someone flies into one. I still have to replace the bridal stays and will get to that sometime.

I will have a forward tramp made from Aquarius as soon as I get the dimensions to them.

After getting it together it is SOOOOOOOO much easier to tack now and it is a LOT faster. I can pretty much out point any boat in the club now. I am probably the fastest boat also but that has yet to be definitively be determined.

Thank you Tom for your patience with me. The boat looks hot and everyone loves it.

[Rhiannon]

I was thinking about doing that upgrade. Thanks for the info. Now I see what Tom was trying to explain. He is very helpful!

[Rhiannon]

Kevin,

When you mounted the eye straps for the tramp, did you tap the 1/8" wall of the beam or use a threaded backing peice like you used for the traveler track?

Thanks
John

[Kevin Keller]

I just tapped the 1/8" wall and it seems to work fine.

Kevin