Fin boxes for sliding plate mast mounts

[faklord]

A few builders are using fin boxes to give a sliding mount, for masts with the plate style attachment. Thinking of doing the same to mod an old kite surf board.
A few ponders:
1) Do these just need to be standard US fin boxes (normally about 10-32 or 5mm screws but could use 6mm with modified plate nuts) or mast base boxes (8mm screws)?
2) Any recommendations for make/source for EU shipping? Chinook look tough but are expensive in EU. Fins Unlimited look like they may be ok?
3) This looks like an option:
http://www.viral-surf.com/shaper/en/50- ... single-fin
The longer versions 12" & 15" could be good for adjustment range and load distribution. Any eerie cue with these or views?

Thanks
Dave

[AndKite]

A few builders are using fin boxes to give a sliding mount, for masts with the plate style attachment. Thinking of doing the same to mod an old kite surf board.
A few ponders:
1) Do these just need to be standard US fin boxes (normally about 10-32 or 5mm screws but could use 6mm with modified plate nuts) or mast base boxes (8mm screws)?
2) Any recommendations for make/source for EU shipping? Chinook look tough but are expensive in EU. Fins Unlimited look like they may be ok?
3) This looks like an option:
http://www.viral-surf.com/shaper/en/50- ... single-fin
The longer versions 12" & 15" could be good for adjustment range and load distribution. Any eerie cue with these or views?

Thanks
Dave

Dave, i bought exactly that finbox from viralsurf, the 15 inch one. Have not had time to put it in the board and test it yet, but it looks sturdy and strong. Bought 2. I will put windsurf mast screw nuts in there, its an M8 screw size. 4 of those i hope is strong enough.

The new slingshot foil board has 2 fin boxes for adjustable position. i imagine that is also a US box, but im not sure.

For me an important point in using finboxes, apart from being able to adjust position, is load distribution. It will make the board resist more pressure from the mounting plate than just carbon or fiber reinforcement.

Im going to put mine at 90mm apart, to be able to accomodate a possible factory foil in the future.

Cheers!

[faklord]

They sound promising then.
Are you planning on wrapping them in closed cell foam, board lady-wise?
http://www.boardlady.com/extrainserts1.htm

Also have checked you can get w/s mast nuts in the slot? And have you found a reasonable source for the nuts or are you going to make your own?

One last thing. If you get a chance can you weigh one?

Cheers
Dave

[AndKite]

They sound promising then.
Are you planning on wrapping them in closed cell foam, board lady-wise?
http://www.boardlady.com/extrainserts1.htm

Also have checked you can get w/s mast nuts in the slot? And have you found a reasonable source for the nuts or are you going to make your own?

One last thing. If you get a chance can you weigh one?

Cheers
Dave

I will weigh one this afternoon for you, going up to the workshop now!

the nuts you can find in any windsurf shop offline or online. I found mine in a shop in sweden, www.surfers.se and my parents brought it down to me.

Regarding the insertion, my man Demian knows all about it. im learning. But i imagine i will set them in some sorf of epoxy foam i have seen him use. Ill keep you updated, check my build thread, will update it tonight.

[AndKite]

One last thing. If you get a chance can you weigh one?

Cheers
Dave

Hey Dave

One 15 inch finbox from viralsurf weighs in at 225 grams, including the square nut that is in there for the fins to use, which i cant seem to get out of there.

Hope it helps!

[tkettlepoint]

I have installed them and they are in a corecell block.. which added a lot f weight in this board having two kinds of mounting system

terrie
www.jellyfishboards.com

[faklord]

AndKite: Thanks for that. That's quite a weight to be lugging around.

Terrie: I'm now wondering whether the corecell is needed. My understanding is it is to increase the bonding surface area to the board core foam. For something so long and thin (as a fin box) i don't see it'll make a great deal of difference? What length fin boxes did you plump for?
Great looking board...what did you finish it with?

Cheers
Dave

[tkettlepoint]

I think of a foil just a big fin.. so a fin that is 900mm long / 32" with the side for force will just crush the eps foam that most boards are made out of . I use a800 corecell to put a block in which help with the side forces. The next thing I worry about is a a 900m/32" knife comeing up through the board slicing my nuts out of me like a stuck pig... if the EPS and glass lets go. The corecell just makes a bigger foot print to help with this issue. there is a carbon patch on the top of the board over the corecell for extra and the whole board has carbon around it too

I have fixed a few sectors over the last couple of years. Their fin boxes are cracking around them because of the side force with the longer fins and not upgradeing the foam around them from eps.

The boxes I use are US box 12" long. If give roughly 3" of movement over all. ( which is a lot for tuneing )

I use house of kolors auto paint for most of my work with a high end 2k clear

I hope this helps out why I do what I do.

[AndKite]

AndKite: Thanks for that. That's quite a weight to be lugging around.
Dave

That is true. But then, i rather have a slightly heavier board that holds up, and that allows me to adjust the positions. I am a beginner both in construction and in riding (never tried) so i rather focus on things holding up for my first rides than building super light stuff... =)