After destroying my last centreboard in the nationals, over winter with the help of my trusty offsider we built a new main foil. Or so we thought …
A combinaiton of cold temperature and potentialy dodgy resin (I haven’t tested this theory yet), resulted in nothing but a big sticky mess of resin soaked carbon cloth. Needless to say, this is extremely dissapointing, especially as there is a worldwide carbon shortage at the moment and I now have to go and buy some more uni’s.
What a pity bruce… good luck with take 3. 3rd time’s a charm so I hear….
I can understand your frustrations as I am also in the middle of building my own DIY foils and have been having lots of fun and games in the process. Probably my biggest frustration thus far is getting my hands on a twist adjuster for the rudder, as Fastacraft has said that they can’t supply me with one, so I’ve got to sort one out myself.
Just curious Bruce; with your flap hinge what did you use in the gap to fill it and did you vary your resin mix at all for the kevlar ‘hinge’ strips? Having tried 4 different mixes and converting a fair bit of kevlar into a tagled mass of yellow fibres I decided to try laminating the kevlar in sikaflex and then filling the gap with sika… seems to have worked OK but it seems a little rubbery and stiff at the moment… which could cause problems in regards to the ride control. it might loosen up a bit if I thin the layer of sika… that’ll be a bit of a ‘suck it and see’ thing, I think. Also, with your case filler (presuming you made one, I didn’t get to see the boat with the foils in it), did you simply take a mould of the top of the existing board and then lay up a ‘blank’ for that bit and then glue the blank to the top of the board at roughly the right angle of attack? If you did that, any suggestions as to how to ensure that the board doesn’t end up with a -ve angle of attack as your first foil (sadly) did?
I am keen to learn from both my and others mistakes, so please email me on jon_emonson at hotmail dot com.
cheers,
Jon
AUS 9255
Hi Jon,
For my foils I used gasket rubber instead of Kevlar for the hinge. The hinge strip is then hole punched to allow the resin to bind it in place. (You can see it in the middle of the table in this photo http://www.teknologika.com/mothblog/content/binary/making-foils/2.jpg I personally have yet to fill the gap, but I have purchased some flexible silicone sealant instead of sickaflex or the task. I personally think that will work better than the sika.
To make the case filler, we moulded the top of a board, but I made a Phil Stevenson “case within a case” which just seems to have too much slop in it, and probably contributed to the identical failures Phil and I had on the same day at the nationals. You should expect a lot of trial and error to get the angle right, and turning the boat upside down and measuring is critical. The exact amount of angle required depends on the all up weight of the boat and skipper, lighter guys require less and heavier guys require more, anywhere from 0 to 2+ degrees. I am planning on cutting my old case apart and being VERY agricultural until I can get the angle correct, then I will probably be moulding a top onto the board.
The current methods of adjustment on most boats is simply sanding and bogging.
Regards,
Bruce