Gidday all,
I have a slalom fin that I would like to convert to a weed fin.
Its 40cm and I want to get it down to something that would be good in a JP V 60 slalom board. Wont be used very often but as its spare I might as well.
Maybe the Mandurah guys could comment seeing they seem to use weed fins a lot?
Oh yaeh, its a Tuttle and needs to stay that way.
All info appreciated.
Cheers,
Larko.
Yep, it happens all the time here, at least 3 of us have moulds of 1 sort or another.
Because the thickness to water flow ratio is reduced by 40% when an upright fin is raked back 45deg, it's good to use a fin that's on the thick side to start with. Or if you aren't too bad with your hands you can bog the whole fin up a bit to restore the thickness to flow ratio. But unless you're confident of shaping a nice smooth foil, it's better left as is.
I've done them in the past without a mould, just made up some thick bog and used the odd layer of fibreglass to give it some strength. Means a lot of work with rasp or surform, then sandpaper to get it to fit good though.
i have converted a heap of stock drakes to weedy...never bothered with re foiling other than sharpening the leading edges up on the smaller ones...they seem to work fine...never...ever spin out.
the only tip i would give is to set them as far forward in the box as you can, most of mine are proud of the front of the box between 5 and 10mm.and most are at 45deg
i use an old tuttle insert for a mould which is mounted square to a piece of melamine so you can measure off to the leading and trailing edges for alignment.
Just remembered that conversion to weed fin topic came up last year on Seabreeze forum:
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=42025&SearchTerms=fin,reboxing
Just as a side note to that other thread
Tried doing the bases with silicone molding and could not get accurate reproduction of bases like Sam had achieved after a number of attempts.
Ended up back on the F'glass split molds again
here's how i made my mould. it works a treat. It has done 4 fins so far with no problems. I got a mould using this rubberised goo stuff stuff. the same as what samoz used.
So what is the theory behind weed fins, as in if I have a 30cm slalom fin what size weed fin would I look at going to with a 45 deg rake?
Thanks guys.
Unfortunately Im crap at doing things like moulds etc.
Its the base I cant get my head around. How do you take off the tuttle base, rake the fin back to 45% and then fit another tuttle base??
Hacksaws dont like me!!
Plus the question Bender made is a good one.
What size would a 40cm come down to suit my JP??
I was looking for around the 30cm mark (vertical).
Cheers,
Larko.
Most if not all weed fin sizes quoted are the veticle size. A 30cm weedy looks quite big.
As far as what size would you need for you JP V 60. If its 60cm wide its close to my Iso86 and that goes great with a my 30 and 34cm weedys. Both these fins started life as 52cm techtonic mirage pointers until they met Elmo's hack saw.
As far as the the bases go. You cut them off keeping the fin blade along as possilbe on a 45deg angle. Then the blade is held secure in your home made jig and the base of the fin is supsended in the mould. just pour in your epoxy resin/filler mix and walk away (remembering to spray the release agent inthe mould first)
Next day pull your new weedy out of the mould, custom fit it to you board and tap the two screw holes and go sailing.
The hardest bit is making the mould and jig. Once that is done is really easy and yo start looking at big pointers and consider attacking them with a drop of hack saw
If weed not thick nor waters infested I recommend to go for 40degrees, performs better
Thanks Bender and Hard's. Ive PM'ed Gazman for his info.
The fin is a stock 40cm Fanatic G10. Its had a hard life with a few chunks missing(fixed) so according to Bender a 30cm would be fine for the JP.
Joe, the sailing spots arent bad at all really but need a bit of upwind work so is 40 degrees ggod for that??
I only have a Select 30cm (which seems bloody huge) for my big slalom board so this is all new for me.
Larko.
i have a pdf doc of my method if anyone is interested....incl pics
the angle can be anything you want it to be...i have found at times at hardies 45deg was not enough...at other times you could get away with a pointer...as hardie suggests
the more rake the harder it is to get back up wind for a given size. as for speed performance... a fin is guaranteed to be faster ......if the weed slides off the end by itself
So you look at comparable depth despite the amount of foil there? A 30cm pointer is substituted with a 30cm deep weed fin?
i cant talk for others but for me i guess i would use a weedy 4-5 cm less in perpandicular height to a pointer (given both fins have similar area)
i.e my iso 105 is ideal with a 34cm (reboxed drake/deb)
and i am guessing the equivalent pointer would be 38ish of course there are a lot of variables _at hardies, where the water is smooth as silk, you can get away with a shorter fin allround
What sort of resin do you guys use to set the fin in? any problems with exotherm (resin generating too much heat?)
