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David Rodgers
3m. cat

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cat sailing

the 3 meter cat project:

Saturday, May 10, 2014
resting on the foil
a shot of the cat with the weight of the hull applied to the tip of the winglet.
tfoi blankthis is a shot of the shaped blanks lightly stuck together. wood, carbon, corecell for the T

Friday, May 9, 2014
3 days of testing the new rudder completed. The rudder has noticeably less drag than the first model. The old blade has been repaired a few times, and has mistakes. It has served it's purpuse, and will get cut down some as it will take some time to build a replacement.
The T foils lift the transom noticibly which is good considering the fact that there is very little aft bouancy. Now i can sit aft once sailing without the rocking chair effect pointing the bows in the air.
The boat pitches less and is more stable from side to side for trapping out. This boat really went from being a little crazy in the breeze, to being pretty well behaved. Putting back the foot straps for down wind trapping should be interesting this summer. They were removed after the first trapping-out tests failed, and now they are going back on.
on the beach
onboard video link https://vimeo.com/94702996


Sunday, April 6, 2014
Lots of junk sailing weather this winter. Here is a shot of the newest rudder project.

t-rudder

Sunday, October 6, 2013
New video on vimeo page. Winglet had started to crack off and had to be repaired. Also repaired rudder housing on regular rudder. Rudders had to be re-balanced for helm. Ready for testing in lighter winds in case there are still some rudder problems to work out. The lee helm caused an accidental gybe/capsize in strong winds and would rather not repeat that. video

Monday, August 19, 2013
sceenshot from 8-13. sailing from the trapeze.
boat shot

Saturday, July 20, 2013
More improvements to the boat includung ability to trap out and addition of a large rudder winglet. Video of latest test session

The day before i took the boat back into the workshop for modifications, i found that i could trap out now that there were lower shrouds and a stiffer carbon race mast. Originally there were diamonds on a much softer mast and it would bend in half under trap loads. Once trapping, a new stiffer boom had to be made. I used the bottom part of a fat wave mast instead of using parts from broken skinny wave masts sleeved together which now bent in half without breaking under trap loads.
So that meant there were 2 major changes for the next go out.
The upwind speed and angle have improved dramatically and the ride is more like a longer boat with the winglet.
Downwind is more under control and jibing is more positive. I think i am holding speed at a much lower angle too. i didn't even know that i was DDW when i went to bear off during the accidental jibe in the video. Maybe just a senior moment….
Obviously the next step would be to make more different rudders and winglets to get to the smallest possible combination that will still do the job.
Making the winglet rudder. Stbd. side.
First i taped a string along the hull to where i imagined was neutral for the AOI of the winglet. Drew a line on the rudder. Took my 1/8" corecell template that i had developed over a few versions using my imagination mixed with what few facts i had, and shaped it down a little. 3 layers (2-5.7 and 1-9oz) . of carbon scraps on each side. The bottom of the foil is pretty flat and i did that step first on a sheet of glass with weights Checked the fit to the rudder and then glassed the top in a plastic wrap and weights to do the bend in the tips. Then glassed on like a surfboard fin with 3-5.7oz on each side. The winglet had a notch that matched a notch in the rudder and was tacked on before glassing. The last glass job was partly to beef up the rudder as well. It's way too much sanding to do it this way, but i am working with what i have on hand.
i wonder what the best way to attach winglets is considering it would be nice to be able to easily swap them out?

 

Marking the angle for the winglet

winglet pic

fiting the winglet with the btm. glassedwinglet pic

ready for hot coatwinglet

Ready for sailing after other rudder is fully repairedwingletpic

heading outwingletpic

Video of latest test session

Friday, June 7, 2013
The boat is back on the water 4 different days. 2 new videos.
all the 3 m. videos - my vimeo page

3m cat
rudders ruddersrudders
tuning the rudder rake and rudder outline.

Saturday, March 30, 2013
Rebuilding is under way. The second crash in the surf caused various damage. Nothing that can't be fixed though.


30knots Wednesday, December 14, 2012

all the 3 m. videos - my vimeo page

old photos slide show

 

 



 

 

3 meter micro cat class box rule:
I. 2 hulls which fit in a 3 meter long recangular box
II. sail, kite, or wing powered
III. 18knt. wind minimum for A fleet racing

 

 

 

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