I just made a bunch of fins in my basement. They are meant for a friend’s fish I am about to shape. This will be board # four, Epoxy over EPS, hopelessly amateur but highly enthusiastic shaping. As I didn’t use any templates for those fins but just made what I thought would feel and work and look good I would be really curious what you think.
Quad set up. Fin dimensions are:
Front: Base: 105mm; Depth: 137mm
Back: Base: 81mm; Depth: 115mm
Both single foiled.
I could still easily change depth (cut off some wood from the base) or the angle between base and leading edge and overall fin area by cutting off some wood or by adding lots of glass…
What I basically would need to know is: will those fins hold (enough surface area)? should I go bigger or smaller? any other ideas of what else i should keep in mind? any help greatly appreciated!!!
Your fins look really good to me and I would love to make and try something like that. Split keels. Nice clean curves and foil judging from a two dimensional image. I almost never make specific numbers recommendations because to me it’s all so subjective. If it looks good it probably will work good. Mike
The foils and templates look very nice. And the fins are attractive to my eye anyway. Placement is toe-in and cant all play into the picture. Without seeing the board I can only give you general info. When compared to a more standard template these fins will not give as much drive or power off the bottom but the will trim nice and fast and release beautifully. I wouldn’t give the lead fins over 5 degrees of cant and the trailers about 2 degrees. Toe in is up to you but a good general rule would be to point both sets right at the central point of the nose of the board. I think you want to place both fin sets of fins a little further aft than standard because of their profile. The board will dictate how far from the rail and the tail block they need to go.
thanks for your nice replies. I thought that it’s not easy to judge fin performance from a 2D picture (without knowing the board), but your thoughts are very valuable. One of the reasons I came up with this template is because I thought that a straight trailing edge is easier to foil with my tools (sanding disk on drill) and skills - and I would get a less crooked result.
Rich, could you clarify why “compared to a more standard template these fins will not give as much drive or power off the bottom but the will trim nice and fast and release beautifully” - is that because of the straight trailing edge? or other variables?
and thanks for your placement recommendations, greatly appreciated!
I figure your fins are flat sided. If you compare the template of you fins to a standard thruster fin, yours are higher aspect and have a shorter relative base cord, thus they will be relatively faster in a straight line and product less drive than a standard template fin.
A board will become more engaged as you move you fin cluster aft. It will be more engaged as you move the fin cluster on either side of the board further apart.
The parallel rail lines of you board go fast but not help it turn sharply and coupled the low tail rocker will help keep the board has the look of a point and shoot type stick. To my eye the fins will compliment the board fairly well.
It’s not going to be a board you can hack and wack with, but locating you fins well will make it go fine.
I won’t venture actual placement measurements, but locations similar to the ones Stretch uses on his boards will probably work reasonably well. Yours is a one off board so you’ll need to put the fins up on the board many times and step back to consider placement again and again.
If the tail is a flat paneled vee the board isn’t going to work very well as it’ll just ride too deep in the water. IMHO your fins would work best on a tail with reverse spiral vee tail
I figure your fins are flat sided. YES. If you compare the template of you fins to a standard thruster fin, yours are higher aspect and have a shorter relative base cord, thus they will be relatively faster in a straight line and product less drive than a standard template fin.
UNDERSTAND; I COULD ADD RELATIVE BASE CHORD LENGTH BY LEAVING A LONG “HALO” OF GLASS OVERLAP AT THE TRAILING EDGE/ BACK OF THE FIN AND REFOIL…
A board will become more engaged as you move you fin cluster aft. It will be more engaged as you move the fin cluster on either side of the board further apart.
MMMHH… CORRECT ME IF I’M WRONG; BUT ALSO READ SOMEWHERE HERE THAT MOVING FINS (TWIN FINS ON A FISH) FURTHER BACK MEANT MORE “TRACKING”, AND MOVING FINS FURTHER UP MEANT EASIER TURNING. IS THAT CONTRADICTORY OR DOES “ENGAGEMENT” AND “EASIER TURNING” JUST MEAN SOMETHING DIFFERENT? AS I READ YOUR POST I GET THE FEELING THAT I SHOULD WATCH OUT THAT THE BOARD DOESN’T GET TOO TRACKY - WHICH IS EXACTLY WHAT I WANT TO ACHIEVE - IT SHOULD BE FAST (THUS LOW ROCKER) BUT STILL TURN EASILY.
The parallel rail lines of you board go fast but not help it turn sharply and coupled the low tail rocker will help keep the board has the look of a point and shoot type stick.
DOES PULLING IN THE TAIL HELP THIS? I PLANNED ON DOING DOUBLE BUMPS…
To my eye the fins will compliment the board fairly well.
It’s not going to be a board you can hack and wack with, but locating you fins well will make it go fine.
I won’t venture actual placement measurements, but locations similar to the ones Stretch uses on his boards will probably work reasonably well. FOUND SOME POSTS ON THAT ONE. COOL. Yours is a one off board so you’ll need to put the fins up on the board many times and step back to consider placement again and again. I WILL POST PICS OF THAT SO YOU CAN COMMENT
If the tail is a flat paneled vee the board isn’t going to work very well as it’ll just ride too deep in the water.
WHY? I THOUGHT VEE IN THE TAIL WOULD MAKE A BOARD TURN EASIER AS IT MEANS MORE TAIL ROCKER? OR IS IT BECAUSE THERE’S NOT ENOUGH VOLUME IN THE BLANK SO A VEE IN THE TAIL WOULD MAKE IT TOO THIN?
IMHO your fins would work best on a tail with reverse spiral vee tail
I’VE LOOKED INTO THAT; HAD NEVER HEARD OF IT BEFORE. SOUNDS COOL BUT DON’T KNOW EXACTLY HOW TO DO IT. INITIALLY PLANNED ON DOING FLAT/ SLIGHT CONCAVE UP TO SHORTLY BEFORE FINS AND THEN START VEE OUT THE TAIL
You change one aspect of the board and you change everything.If you double bump you change everything IMHO. So figure out what the outline is going to be and stay with it. That’s where you start. Make up your mind and go with it.
First comes the board, then the fins.
IMHO things need to be done in that order.
Single to double concave will work fine on the board. Just keep the concaves at less than 1/16". Let the vee in the tail go toward flat as it exits the board and you have reverse vee.
You can add more area the the fins once they’re on the board. it’ll just be extra work. Maybe you should put the fins on the board the way they are and go from there.
On fin placement and tracking we’re on the same page.
If you pull a tail in that is already thinned out the board will not go well in small waves. If you leave the vee panels in the tail flat the same thing will happen.
Thanks for the advice, I will try to do it step by step
I still have a question on bottom contours - new questions are coming up with every answer I’m getting here. I have search the archives but not found an answer on this one… maybe it’s a stupid question but:
how do I shape a vee that goes flat - " Let the vee in the tail go toward flat as it exits the board and you have reverse vee" ?
do I first shape a consistent vee out the tail (thereby trying to get a continous rail rocker) and then take away at the stringer towards the tail in order to make it more flat?
OR: do I put in a vee, say under the back foot, and NOT put in a Vee in the last few inches of the (fish) tail at all?
this second method would leave more volume in the tail, BUT: I have a problem visualizing it, as I think my rail rocker would get uncontinous (increased rocker where vee starts, and then lesser rocker where it ends, kind of flat).
Thought I post pics of my progress with the board. i forgot about the fin question for a while and went on to shape the board. It’s the first time I use a blank from atuacores, till now I used insulation foam or stripped old windsurf boards… it’s their high density EPS, and although I was a little worried about EPS bubbles tearing out of the foam and leaving holes I really liked to work with it - finishing it with 180 grit leaves a very smooth surface. Stephen from atuacores was really helpful and answered all of my questions, i think I wrote him about ten mails till now, so that’s great service in my opinion. here’s a first picture taken right after laminating the deck:
It’s 6,0/ 20,5/2,6. I am excited. first clear lamination. first board with new tree logo.
I tried to follow your advice and kept the bottom contours very subtle, it’s a single into a double concave going almost flat behind the fins with just a slight v out the tail.
tomorrow i will work on the fins… as Stephan did not like them that much I made new ones (and I think about using the ones I posted for my next project).
Very progressive fins. It would be an interesting combination with the retro shape which tended to have more keel style fins which are yours rotated back another 20 degrees or so to the bottom. By rotating them upright you go forward …future retro. Thats cool, making it a new rewind, or a fast forward . I like your logo too…very spiritual Druid/Zen vibe!.. transcendant… timeless. Nice combination of design elements.
thanks for your reply, here’s the zen logo close up:)
I was really satisfied with my rails this time, I had a nice tucked under edge - which is mostly gone now, after the lam… I hope I can bring it out again with sanding… i will post. take care,
So I finished the fins. They are made of plywood, like the ones I posted in this thread, however I glassed them with pigmented epoxy. It wasn’t my idea, cause I do like the look of wooden fins. And I also thought my eco friendly, vegetarian friend Stephan would like them too, but no - he’s more into plastic when it comes to surfboards, so he said
Anyway, made the red fins for him, here’s a pic after glassing them on:
I used McKees fin placement recommendations - awesome site, really generous to publish all that data:
