Forums > Windsurfing Wave sailing

Turning a Evo 75 into a twinfin

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Created by Stefan > 9 months ago, 3 Aug 2009
Stefan
9 posts
3 Aug 2009 12:20AM
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Hi,

Since September '08 I have Evo 75 XTV 2008. I am/was new to wavesailing so I damaged the board quiet a lot in the past time by bumping into rocks, getting washed in shallow breaks and crashing jumps (north Fuerteventura is great for your material...). Now I discovered some damage to the finbox and the surrounding area on the bottom of the tail. A friend of mine had a really nice idea: would it be possible to remove the finbox, fill up the gap and make it a twinfin?

I really like this idea, but it does rise me some questions:

-Is the shape of the evo able to work with two fins instead of the orginial single fin setup?
-If not: what kind of changes does the boardshape need to work with a twin setup?
-Where would be the best place to put them (I understand that it should be somewhere in the same area as the orginal finbox)?
-How will the fins influence the character of the board?
-Since I'm only 65 kg the board is quiet big for me and in big waves and highwinds I can't maintain control in bottumturns and I don't have enough weight to put pressure on the frontfoot/rail (especially around the mastfoot I think the board is too wide/fat for me and forces me to turn on the backfoot), will a change from single to twin improve my control in the bottumturn?

I hope you guys have some usefull input for me!

Best regards from Holland,
Stefan

windgeorge
WA, 108 posts
3 Aug 2009 1:14AM
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hi there the shape of the starboard twiney is not the same they have a swallow tail . you could try it but you would be better off fixing yours and trade to a kode . have look at your fin size try 21 not a drake fin mfc, choco etc . make sure weight is forward on board put fin in front of box,and mast track in foward postion. see how you go

Stefan
9 posts
3 Aug 2009 2:21AM
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Thanks a lot for the quick respons. I have sailed almost always a 21,5 cm MFC 2K, defenitly a big improvement comparing to the 23 cm standard Drake. Especially because it gave me less lift so I was more on the water then flying uncontrolled over it. My waverideskills obviously can still improve lots, but on an other board (I borrowed an old D'light for a few times ) I had more speed and control in the bottumturn. In this link:

you can see around 4.19 my most recent wavesailingskills. As you can see the board is quiet far out of the water and I'm leaning quiet far back. Ofcourse I have to practise even more getting the pressure more to the front but I heard from several surffriends that I needed a smaller board to improve simply because I don't have enough weight to give sufficient pressure on the rail.

hoop
1979 posts
3 Aug 2009 9:24AM
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I reckon you should give it a go. You'll have to do a bit of work if the boards damaged anyway.
Rout the old box out and put in a pvc block to fill the hole, then glass over it. Rout 2 holes for new fin boxes, put 2 pvc blocks in. Then flush them up ,rout some holes for your new fin boxes glue them in and glass over. Bog ,sand and paint. Done.
I think you should have your new fins about 40-50mm further forward than the old one.

Rider5
WA, 567 posts
3 Aug 2009 8:21PM
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Stefan go to my profile and check out some of my pics I have converted two boards with great success, I think you will improve your board by doing it. You could also covert it to a quad as star board say that they have used the evo shape and converted it to a quad. Don't worry about the outline difference.
If you are going to go a twin, keep them parrallel I try not to place them so that the trailing edge of the fin no closer than 5cm to the rail, the rear of my fin boxes are about 15cm from the tail. I have varied the width apart from 12cm on one board to 14cm on another board.
The twin fins will change the board so that it turns tighter arcs, it will not become as uncontrollable in strong winds as a single fin, If both fins are large enough it will plane earlier and point upwind better, yet still be looser than a single fin.
Go for it, good luck

Stefan
9 posts
3 Aug 2009 10:56PM
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Thanks again for the advise, really helps me out. Good to here that I'm not the first one with this idea! I will show how it goes.

Crash Landing
NSW, 1173 posts
4 Aug 2009 9:40AM
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How much do you think it would cost to get someone to convert it? I have no tools, no materials and no idea but I do have a board begging to be converted!

Long Reef
SA, 583 posts
4 Aug 2009 10:09AM
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The Boards.co.uk website has a long forum on this with pics - there was a lot of DIY conversions that appeared to work. The amount of toe-in on the fins is very important.

Rider5
WA, 567 posts
4 Aug 2009 2:41PM
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After just looking at the quad I'd like to retract my statement that they have used the evo shape and converted it to a quad. The bottom vee and contours look very different from the Evo.

P.C_simpson
WA, 1491 posts
4 Aug 2009 10:58PM
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Rider5 said...

After just looking at the quad I'd like to retract my statement that they have used the evo shape and converted it to a quad. The bottom vee and contours look very different from the Evo.


Yer they have definately started from scratch with the new Quads, even look heaps different from the twins of last year..

Stefan
9 posts
6 Aug 2009 10:34PM
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Thanks for all the reactions again. I had a answer of Ola from Starboard and he told me a quad setup would also be a good idea, so I'm doubting now what to do. Point is that a friend of mine will do it so it depends on how much work he wants to do. If a have made a decision I will post some pics about the transformation. Until then I've got plenty of reading material to kill time. Thanks again and I wish you guys some nice wind and waves on the other side of the world.

nick0
NSW, 510 posts
11 Aug 2009 5:48PM
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im a aprentis shipright so i deal with that kind of work all the time ...... i would buy ur fins .. then cover the top of fins in mold relise tape and mold relise cream .. then rap some carbon around the top of fin ... router 2/4 chanels out of the bottom of ur board ... say 5mm bigger than it needs to be ... set up come clamps to hold ur fins in exact positions..... fill the channels big a glue bog and set the glass that was raped around the top of ur fins into the bog filled chanells..... let it go off sand and fill with car bog ... wallar

gazza
WA, 647 posts
12 Aug 2009 9:31PM
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nick0 said...

im a aprentis shipright so i deal with that kind of work all the time ...... i would buy ur fins .. then cover the top of fins in mold relise tape and mold relise cream .. then rap some carbon around the top of fin ... router 2/4 chanels out of the bottom of ur board ... say 5mm bigger than it needs to be ... set up come clamps to hold ur fins in exact positions..... fill the channels big a glue bog and set the glass that was raped around the top of ur fins into the bog filled chanells..... let it go off sand and fill with car bog ... wallar



Mate thats the best spelling I've ever seen especially the bit where the fin was raped by the glass.Not quite sure how that works though?



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"Turning a Evo 75 into a twinfin" started by Stefan