Seems my 48cm is too wide for Shark Bay so a new 42cm board is being contemplated.

So how narrow can you go at the fin, before sucking air onto the fin becomes a problem!

Most boxes are set in about 9cm from the back, but I think width at the front of the fin would need to be more than that, as it's easier for air to travel sideways than backwards.

i'm assuming your 42cm board is it's max width?

the issue with tail width i don't see as being an issue with dragging air in. with a board that narrow you would have (in my opinion) some v in the tail for control.

the issue is more ergonomics, how big is your foot?

oh, and how much power do you want when gybing.

Decrepit, I just took some measurements of my Love Muscle Small speed board CAD file. This board is 43 wide and has a very pinny tail It is quite wide at 430 off where the wingers start then steps in 15mm a side @ 430 into the pin tail. Not sure you would want to go any smaller in the tail than this???. I have had no issues with sucking air or spinout.

@200 from tail it is 210mm
@300 from tail it is 253mm
@400 from tail it is 286mm
@430 from tail it is 322mm, this is in front of the steps, 15mm per side.

I hope this may be of some help to you.

Oh, forgot an important one. @ 90mm off the tail, the back edge of the fin box, it is 139mm, so really narrow.

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mr love said...

Oh, forgot an important one. @ 90mm off the tail, the back edge of the fin box, it is 139mm, so really narrow.

that's narrow eh.

does your heel hit the chop?

Chop???? this is a speed board

No, although the tail is narrow it is quite chunchy, plus the back hole of the back strap is on centreline (through the front fin bolt) and the front hole slightly offsett.

My back shin cops a fair bit of spray though, I think due to the wingers and really narrow tail.

I,ll take some photos tonight.

clever idea, when i did mine (which is wider - 80lt) i was getting concerned about tail width and chop. i started to exprore asymetric foot straps but figured upwind would be an issue.

i like your solution, it deals with both outcomes.

the dims on mine are

90 off - 160mm
200 off - 255mm
300 off - 317mm

which granted if it were a 42 wide board it would be narrower.

photo in full flight. 41 knots from memory

Good point about heel hitting water with the JP45 I wonder about running a single strap as I was constantly battling trying to find a foot position where my rear heel was not constantly being hit by speeding water. Alterntively i could have my feet reduced in size (cosmetic surgery seem very popular now)

The tail width on my Carbon Art CA40 is pretty narrow. Can't measure it at the moment as I am not at Sandy but maybe you could find one to measure?

I had the foot-strap inserts customized for an old fashioned 'wide' foot-strap (Non adjustable Gaastra - but DaKine made a velcro adjustable one). Two narrow straps are too wide/clumsy, one normal one is too narrow for good control. I will get some photos and post them with widths as soon as I am back at Sandy.

I have never had trouble with fin sucking in air, even on the older much narrower tail speed needles. (and some are so narrow that you have to twist your foot sideways to stop both ends dragging in the water!)

Evets, You woudn't want to do that, big feet, big............shoes

You can see the very pinny tail on the Luv mus small. never had an issue with spinout, fin sucking air. Doubt you would want to go much narrower though.

The tail still has a fair bit of volume and has the back strap hole in the front fin screw and the front hole slightly offset. I find it pretty comfy.

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mr love said...

Oh, forgot an important one. @ 90mm off the tail, the back edge of the fin box, it is 139mm, so really narrow.

The back of the fin box on the ca 40 is 142mm @ 92 from the tail

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Gestalt said...

clever idea, when i did mine (which is wider - 80lt) i was getting concerned about tail width and chop. i started to exprore asymetric foot straps but figured upwind would be an issue.

i like your solution, it deals with both outcomes.

the dims on mine are

90 off - 160mm
200 off - 255mm
300 off - 317mm

which granted if it were a 42 wide board it would be narrower.

photo in full flight. 41 knots from memory

Ah Fond memories awesome spot

^^ what's that, you need a 42cm version

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Gestalt said...

^^ what's that, you need a 42cm version

Yep one for each foot

Thanks everybody, great info.

So 200 from trail no narrower than 200, and about 150 at a 100 from the tail.
I'll see what I come up with.

I've got very short feet, so that shouldn't be too much of a problem.

Evets/Daffy, did you see the back strap on my 53? Keef inspired, just made with pool tile foam and harness webbing. very light and cheap, can be made to suit your feet on that board.




I've gone back to dakine on the front, for some inexplicable reason I couldn't gybe with keef's straps.

apologies in advance decrepit....

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vando said...

Gestalt said...

^^ what's that, you need a 42cm version

Yep one for each foot

you mean like this
patents.google.com/patent/US4534305

what's the width at the rear strap though. 250-300mm in from tail.

behind that could be whatever you wanted to suit your design. looking at martins tail it looks like his rear strap is forward which buys him some more width.

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decrepit said...

Thanks everybody, great info.

So 200 from trail no narrower than 200, and about 150 at a 100 from the tail.
I'll see what I come up with.

I've got very short feet, so that shouldn't be too much of a problem.

Evets/Daffy, did you see the back strap on my 53? Keef inspired, just made with pool tile foam and harness webbing. very light and cheap, can be made to suit your feet on that board.




I've gone back to dakine on the front, for some inexplicable reason I couldn't gybe with keef's straps.

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decrepit said...

Thanks everybody, great info.




I've gone back to da kine on the front, for some inexplicable reason I couldn't gybe with keef's straps.

hey decrep there's an upgrade , all 3 straps are tapered for ease of gybeing, the back strap is on a ca44 back measurements 100 back to 50 front and still about 55gr

looks real pretty keef.

yes decrep unfortunately the ones i sent to you were crap , they were too stiff the new ones are prefect you know i sent a proto strapp out" stitched and similar to the one in the pic " the feedback was it wasn't strong enough for his custom proto at 50 knots its great to get feedback because there not making this stuff so nothing to compare with
what i found with the tapered strap is its easier to rail the board over with the strap being wider at the back and easier to get your foot out when running off the wind to gybe , after saying that i'm still working on them there's always room for improvement