Monday, March 31, 2008


laid up all the carbon on friday, laminated the 3 bits together today. went fine, im happy with the amount of material, though this time i didn't reinforce the skin so much at the exit point and at the T-Joint. There was still ample weight of carbon in those areas but, the weakness last time was in how i dealt with the shear loadings.

Anyway i've improved the sheer resistance in a couple of ways, the result of which will hopefully be a long as prosporous, successful life for the foil: (carreer as a banker, hot wife and a couple of kids, townhouse in central sydney, big boat etc.)
  • First of all the T joint has no foam in it at all, just glue (sp microfibres). Last time it was foam and bog (Q-cells) with carbon strands in it, that wasnt enough.

  • There is some diagonal carbon along the front and back inside edges in the areas of high shear stress - i just chuked it in there with a big glob of glue in the middle; the idea is that when the mould squeezes together it gets pushed to the places the glue is oozing out.

  • you can see in the photo I integrated my carbon T-piece into the bottom surface, that pushed straight up into the foil and is encased in glue. hopefully there is no way in the world it will separate from the bottom skin, or pull out of the strut.

  • Lastly i plan to further tie the leading and trailng edges of the foil together around the T joint area and the exit area by making carbon 'wet bolts', at about 30-50mm centres for about 250 - 300mm, to join the top and bottom surfaces. ill put photos of them up when i do them.

Also i cut my finger twice in the same spot with the grinder. first time with the cutting disk then again with a sandpaper disk. the second time it went straight through my nice fresh band-aid. I put a heavy glove on after that. When you wear a glove you might as well have a bit of wood for a hand.

Friday, March 28, 2008

waxed and ready

I think this is turning into a way for me to summarise my days work, so i can swich off and so it doesnt keep me up half the night planning anf recapping. and mistyping.

anyway i thought id get the foil laid up today, but kinda ran out of time and oomph.

made a last minute alteration to the mould; something id been planning to do but forgot about. its made out of some thin acrylic filled with araldite/Q-cells, took 5 minutes to set. stoked. i wanted it to be quick as at that point i still thought id be putting some carbon down over it tonight.

Its there to create the gap between the foil and the flap, so i dont have to cut a gap and thus stuf up the carbon skin. also last time i had to reinforce the centre of the flap from the outside after id made the cut, this time i can do it from the inside and it will all be flush. saved some time. its a bit rough cos i didnt sand it at all, just chucked wax straight on, but itll do. may have to bog the foil slightly (probably will anyway, as the fibres wont want to bend around, and i dont have a vacuum set up yet.)

Came to the realisation that i should have wet out the flap hinge in position in the mould, and stuck the plastic spacer strip on it there too. now i have to glue it in with PVA, and glue the spacer onto it. hopefully the mould type PVA will stick it. I wasnt organised yesterday to do that, so it never would have happened, but for next time...

Also completed step 2 of the cams, ill see how they come out tomorrow. ill bake them with the foil so ill post a photo of the finished product. i think they will be ok.

The carbon is now cut out too. its such a shame to cut up those big perfect sheets, but you gotta grit your teeth and do it. and hope you get it right. the hull became a pretty good bench, at 21kg bare, i think it is almost better as a bench than as a hull. anyway thats a couple of projects down the track. Oh also i cut a hole in the hull that i really shouldnt have cut... more on that later.

Finally i just want put it out there and say thanks to Andrew and Scott at CG composites for being so helpful with the resin and reinforcements, bog, glue, and peel ply etc. and to Mel and Miller and David at Glascraft Marine for putting up with my crap. From those two places i've been able to get 90% of the materials I need to keep this project going, and some good sound (and patient) advice, which has probably been the diference between a semi success (so far) and a complete cock-up. also Bretts/Bunnings you're both wankers, though 'Tube Sales' at Yatala i like.

Wednesday, March 26, 2008

gantry mould, cams, foil prep

Unrolled the sail today and noticed that its not only completely shagged, but i was missing 4 out of 5 cams. i think i gave them to emo in return for partly busting his sail. so anyway i've half finished a new set of 5 out of carbon, i dont think there will be any weight saved rather its just easier than finding where to buy them. when theyre done ill decide whether theyre good or not. i hope they dont snap in a race. just one more thing to go wrong.

also laid up the T piece to tie the bottom plate of the foil into the T joint, and also the tang to attach the gantry to the transom (in the same mould.) mould looked cool i took a photo. The T piece i will drill some holes in, to make sure it bonds well to the bottom plate, also i will put a couple of layers of carbon over the top of it.

Did the hinge as well, had an interesting incident with the leftovers of my hardener-heavy resin (to make it a bit more flexible than normal) started smoking and actually boiled and set in the tin at the same time. must have been hot today.

Saturday, March 22, 2008

construction commences!

about a year late... but hey. what can you do.
hopefully it will all be done in time for the states on the 19th of april. if the new foil's maiden voyage is race 1 then i guess that constitues success. !.
The foil is designed with some sneaky new improvements, and i have re-surfaced the moulds (they are a fraction more accurate to the NACA shape now) and added and subtracted aluminim strips as appropriate. The front edge of the foil is now 10mm forward of the strut, so that the rod has more leverage on the flap. I've stuck the moulds back together like before, so that all the angles are adjustable, using longer bolts this time, and the result resembles some kind of fusion beween a smoked chedder and a jarlsberg. lots of crumbly holes. whatever, they'll get covered in wax and resin anyway.

I've also designed a new gantry, maxed out to 500mm, as the spacing between my foils is, well, close, due to the limitations of working with an existing boat. Ill make a good mould for this so that sometime down the track, if need be, i can make a good, light version with my vacuum gear that im going to buy when i get cash. Although if there is a new hull, there may as well be a new gantry. orrite so ill make a slap-up mould. or just buy vaccuum gear now.
I've sussed out a (hopefully more effective) new rudder flap adjustment system using a piece of string and a cleat and some elastic/pulleys etc. we'll see how that goes.

also my stsainless cables inside the foils are going to get replaced with some nice smooth fibreglass rod. the centreboard first, the rudder may need to wait until after the states. Ultmately there will be a bladerider style tube through the foredeck so i can do away with the friction-friendly throttle cable. and a new wand hinge mechanism.

i have my work cut out for me i guess, but im on holidays this week so ill get right into it and see if i can't get a foil laid up and a gantry laid up by next friday
to buy:
release wax and PVA release agent
fibreglass rod & end fittings
new wing tramps
some rope and pulleys