twin fin fish with plywood core D fins:where and how big

*scratches chin…

im makeing a ‘retro’ fish for a local shop and want to glass on D fins

the boards stats are: 6ft long,18inch nose,22 mid,17 tail,plenty of nose area and volume (2 3/4 thick)6 inch swallow (curved edge(like the rail)).

what size should i make the fins and where should they be placed?

any help/advice please

ps. hope the east coast usa crew come through ok


If you make 8" chord by 5.75" depth fins, single sided, I’d go with the trailing edge about 4" from the tip of the swallow tail, for bigger, steeper waves.

Oh, East Coast…better make it about 5" up from tip of the swallow, and maybe cut the depth down to 5.5?

i was wishing the east coasters well in the present climatic disturbances…i speek to a few of em online,maybe a few hundred more board sales and ill get there.

the fin size sounds ok…but that far back?

i aint ever surfed a fish before,so this board is a bit of a shot in the dark and all my guru says on the subject?

“make it a single and be doone with it”…he says that about any board i shape though.

thanx for the reply btw

8" chord + setting the fin up 5" means leading edge at 13" up from tail.

The board is only 6’ long, your rear foot has to sit in front of the fin, but almost atop it, to turn sharp and snappy.

Any farther forwards also works, if the WP is well forwards, and the board is designed to be ridden from the middle.

what u say is true…was distracted when i read ur reply.i found a link to mandala custom shapes: keel twins,twinzers,quads and singles.

the fish in their gallery is a similar template to mine,except in width.

another Q:

do wide square tails work with a single fin setup?

Sure, but they actually require more fin overall, either sides, singles, or a combination. Squares have the most surface area, so more fin is needed.

LeeDD ,

My board size 5’6" , does the fin setting still remains the same as “leading edge at 13” up from tail" ???

Fin size 8" x 5".5

Thanks …

That would depend where the WP is, how tall you are, your leg length, and your preferences as to surfing off our back foot.

Mostly, the reason for riding a shorter fish is snap and instant turning, so standing farther back achieves both. Meaning…you have to stand further back, need the fins further back…so maybe the 4" from tail idea is good. But it depends if you really lean on your back foot, or you are a trim and glide surfer.

LeeDD ,

I been surfing shortboard for bout 4 years , can’t do quick turning on any board bigger than a 6’4" . I have weak back foot , i lean more on my front foot . Just wanna make sure all dimentions are what i need , we don’t have local (Malaysia) shaper . I have to pay us$380.00 just to get out of my country to get my board done .

Apologize for my poor english .

Regards ,

A .

Attach pics of my local break … enjoy .

i would consider the main goal of a fish to be longer more drawn out turns. i put 9"x5" keel fins 6.5" up from the tail and the board is very very loose, but can still hold a rail when you turn it on the pin tail.

I have recently made a retro fish,5’7",19x22.5x18,I’m not very experienced.

I called a profesional 300 boards+,he looked it up and came back with 7.7-8" up from tips,using some old glass 5.5" fins.This thing turns quick and still gets alot of speed for sections. Roostersurf