I'm about to start building a longboard. It's designed as a raceboard. I've got some rough planshape dimensions from images of imco, equipe, f2 etc. The rocker is more of a guess - flat tail blended to a fourth order polynomial. Deck - just what looks nice.

But I'm unsure of how much vee to use (not going to shape any concaves). I'm thinking 1degree along the entire length. It would be great to hear ideas on this. Better still if anyone has the time to place a straight edge across their board and tell me how much it sits above the rail. Also what about tail kick, I was not going to use any.

Mal

Hi.

Nice to know somebody else who builds its own boards.
All my boards except a Dufour wing were all custom made by me.

By now I'm planning to build a tandem board to sail with my kids but the question is gemini( starboard wide like a formula board) or Mahalo (kona).

I'm not sailed any of them only a formula style freeride (245 x 86 cm).

Sailing non planning with the flat and wide front of the gemini do not convinces me so some sort of "V" at the front will be a must by now.

Also the rocker line as you mention for me a flat planning area must start aprox 10 cm in front of the daggerboard case.

Are you going to use sandwinch construction?

I'll appreciate your opinion.

Thanks and regards

Ignacio

Hi.
Just found some sideview image of a long board.... look at www.nelsonfactory.com

Ignacio

Years ago, all of the top shapers would say that the correct rocker line is absolutely critical; a real make-and-break factor.
Apparently it's still the case.

Unless you borrow the shape of a similar proven board, you could have a wonderful time building a slow new board.

yep.... that's the beauty of doing it yourself... you start to sail many months before you start cutting styrofoam....

I live in Chile south america here there is not a single tandem board, only one of Starboard's retailer and, of course, they don't let me take any measurements...

To start most of the pictures of starboard gemini shows aprox 1/3 of board length out of the water when planning for a theoretical guy of 160 kg in between the two straps positions.

So wish me luck.

thanks

Ignacio

Hi Ignacio

Just to be clear, are you suggesting I keep some vee at the front of the board?
My understanding is vee reduces the planning lift force therefore too much at the back would degrade planning performance but at the front I think more vee could be tolerated and in fact may be desirable. As I say I've designed it for 1degree along the entire length.

Yes the construction will be sandwich. I'm hoping to have it all done by the end
of October, I'll post details of the design and construction once I've finished.

Chris,

Agreed rocker is the primary design parameter. Unfortunately I've only got one reference board it's an AHD eliminator late 80s? I've measured its rocker but it's a fairly coarse measurement so I didn't use the data directly but it gave me a guide for my rocker curve eg. the location where the rocker starts and maximum rocker at nose. Interestingly the comparison with the image Ignacio pointed out is quite close, although I'm not sure if that's just an artists impression. I can't find any other images of rocker profiles. In the end the board is for light wind recreation I'd like to give racing a try but don't think there is any activity around here. Perhaps I shouldn't call it a race board, how about board for light wind cruising.

Mal

Hi again.

Jonesmb please try
http://www.americanwindsurfer.com/tests ... index.html

here you can have more sideviews of longboards.


Ignacio

Plenty of forward vee in the Konas. Carries back thru the tail on Mahalo and the One. Vee smooths the ride. Good luck.

Finally finished here are a few photos

Hopefully will give it a test at sandy point in 2 weeks. I've written an article on the design and building process if anyone is interested let me know and I'll post it.

Mal

BEAUTIFUL WORK!

Please post your article to us at LBWS so Rob (the main man here) can post it.

It's great to see someone building their own again.

Impressive, mate. I was involved in the '80s with a local builder, making our own can-openers (asymmetrical boards). Was a hell of a job, messy work.

So I really appreciate your board here...