Single fin Placement

Just made a single fin and about to put the box in. Its the short box. How far do I put it up from the tail. Its a 6’3 / 20 / 2.5 similar outline to the Merick single fin except the wide point is 2" up from the centre.

Keep well

Depends on the size of the box, and type of box. The size of the intended fin, and width of the tail are also factors. More info needed…

Not to mention personal preference, location of WPoint, thickness profile, rider style…

…waves to be ridden with it, favorite color, and -most important- a photo of your girlfriend would help, too.

Tail Width is 15 inches. I think is is a Std 7.5 inch box. (the Short one) not sure on fin to be used so you can advise on thatn as well


…before I do …

need to know

what football team you support

who makes the best pizza where you live

what beer do you drink …

if I think of anything else , I’ll let ya know mate …

cheers ,

ben

[p.s. - I sent a pm , with the serious answer, by the way]…yes the above is jokes.

what football team you support : Rugby\ South Africa and any team playing the Aussies

who makes the best pizza where you live: Pizza in the UK is Crap. best place is Stable in Still Bay and Butlers in Cape Town

what beer do you drink … :As long as its cold but I am more of a Wyno though.

Now can I get an answer?

Swifty,

I’m going to make certain assumptions: 1. Bahne FU box. 2. Fin depth 7 1/2’’ to 8’‘, 3. Fin base 5’‘, 4. Front tab on the fin (one inch added to the base length) So…I would set the FRONT of the box 11 1/2’’ up from the tail, this would put the leading edge of the fin at 10 1/2’’ up from the tail, and still give 1’’ of adjustment to the rear if you wanted to use a shorter fin, which MAY need to be moved back some, for proper bite in turns. A rear tab would allow a more forward initial fin placement, or adjustment. I’d rather see you using the 8 1/2’‘, or even the 10 1/2’’ box, so a greater range of adjustment, fore and aft, were available to you. Fin position is an extremely important factor in dialing in the max performance level of a board, and tuneing the board to your personal taste and style. Others may benefit from your report back, on your experience.

Quote:
Swifty,

I’m going to make certain assumptions: 1. Bahne FU box. 2. Fin depth 7 1/2’’ to 8’‘, 3. Fin base 5’‘, 4. Front tab on the fin (one inch added to the base length) So…I would set the FRONT of the box 11 1/2’’ up from the tail, this would put the leading edge of the fin at 10 1/2’’ up from the tail, and still give 1’’ of adjustment to the rear if you wanted to use a shorter fin, which MAY need to be moved back some, for proper bite in turns. …

When I did the RFS single fin R&D, I measured scads and scads of singles to see where the fin positioning would be optimal.

All boards from 6’ to 7’ had the leading edge from 11.5" to 13 inches up from the tail.

On a board 6’3" I would guess the best leading edge position would be between 11.5" and 12" and you will never want to go outside the range of 11-13". This is the measurement from the tail to the leading edge of the fin at the base. With the fin at 10.5" my guess is turning would be a real pain.

Per your comment,… that’s why I made the recommendation of the larger box, to afford a greater range of adjustment fore and aft. Your findings are very close to the ranges I established in the early 60’s. I just never told people about it. It was my ‘‘secret advantage’’. My personal optimum range, depending on certain variables, is 11’’ to 13 1/2’‘, to the leading base edge of the fin. I do however disagree with your conclusion that turning would be a ‘‘pain’’, with the leading edge of the fin set at 10 1/2’'. Good call about the proper placement range. BUT…now everyone knows!!

AWR I hate to be a kill joy

but how thick is yer tail?

how thick is the box?

set the fin up far enough so the box dont go through the deck .

Just a thought…

ifn’ thet tail 's too thin glass a fin on till ya hate it and then…

take it off and glass another on

in a diffrent spot.

…ambrose…

remember glass ons arent necessarily permanent

though they remove much slower than removeable fins

lthough in a finely focused fit of rage

a glass on fin can come off very quickly

Just curious, i have a single fin with a swallow tail. where would i measure from? the end of the stringer or a line across the tips of the tail?

I have been toying with making another single fin one based on this but with a pin tail like the pic above.

I find i need to move my fin based on whether i am going to be surfing backhand or forehand. luckily i usually only surf it on my local point break so dont have to adjust it very often.

Scot,

The most meaningful measurement would be from a line drawn from tip to tip, as you suggest. For a pintail design you can place a single fin anywhere from three inches, to six inches more forward, depending on how “severe” the pintail is. It helps if you think of a pintail as a squaretail with tail rail extensions.

Thanks Bill.

I am making a 7’2" single fin short board style. Would it be safe to assume to place it 13.5 up from the tail? the fin I am going to use is a 7" fin with almost 7" of rake.

iSLANDa,

If you are referring to the base of the leading edge of the fin for your measurement, then yes, that fin placement would work. What is the type of tail, and what is the tail width 12’’ up from the end of the tail? If it’s too wide, you may need a little more fin, or need to move the 7’’ fin back an inch or two. Are you glassing on, or using a box?

My tail measurement is about 14.5". I am using a 7.5" short board fin box. Here is a pic of the fin I am using, and the tail is sort of a round pin, more round than pin. I took a gun design outline and added 4 cm total to the outline. I probably should have kept the tail a pin but I think it will ride half descent. Last night I glassed the deck 2-6 OZ and 1-4 OZ. Thanks for the input!

I finally put in the fin and placed it 4" up from the tail and its a 10" box. I think that should give me a good range.