fin cant

General Discussion
1

the final steps on my first shape ever. eps at that. having a bit of problems, but made a jig that did me great on the center fin, but an gettin all kinds of mixed info about the cant on the rail fins. anything from 4 degrees to 14. whats the difference? i want something standard as to not put another variable into the evaluation of my first shape.

so whats a goo average cant for a 6’6 2 3/8 thruster?

thanks.

2

Standard thruster cant is 4 degrees. Make sure

you set the boxes with a fin installed (or a fake fin)

if you are doing your own glassing. There are

a couple of threads here & on SMag forum about jigs

and tools to use to do this. Check um out.

3

Depends on your bottom. Standard for most concaved shortboards is 7 degrees. You can get away with 6 for mild concave, 5 for a flat tail, and as low as 3 or 4 for panel vees. Extremely deep concaves can need as much as 8. A good test is to measure your rail fins at the rear of the base at the surface of the board, from side to side. Let’s say it’s 11". Now measure from tip to tip. You Should have minimum 7/8ths greater measurement at the tips, and as much as 1 and 1/8ths on radical concaves. If you use this rule this will keep your board from being “sticky” and going rail to rail good regardless of bottom contour.

4

More cant - looser setup (but more drag)

Bigger concave (flatter rocker line, so potentially stiff) - more cant

5

Yeah, follow what Jim recommends, he knows best.

I was quoting the formula for a vee shortboard, single

concave into panel vee that I usually use as a backyarder.

6
Quote:
SNIP

so whats a goo average cant for a 6’6 2 3/8 thruster?

thanks.

[=Blue]Aloha Surf3184

You can check out this subject in detail on a past thread at…

http://www.swaylocks.com/…d%20toe%20in;#230194

Many participated with great input. My extended comments are in post #25 and #27.

To answer you more specifically more data is needed. The missing data in your question above is … what your boards bottom is like. Since most measure Cant in degrees from the bottom (zero point) of the board at the fin placement point, you need to know what that bottom plane’s angle is to a level horizon.

For example, a flat bottom would be a level Horizon (zero degrees) and a safe fin angle would be 5-6 degrees tilted out from that zero or the level horizon. But on a vee bottom the side of the bottom is already tilted out a couple of degrees depending on how much vee the board has so you might only want say… 4 degrees from the vee plane’s zero point even though that zero point is not a level horizon or really zero to one.

A concave bottom on the other hand, is already tilted inward and will then require more fin cant to compensate for how much the concave has tilted the bottom off of the level horizon. So you might need around 8 degrees.

Many current pros are using fairly low angles of cant on their boards. These guys are often super powerful surfers and they find the more vertical fin cant to bite for them better. They are also incredibly skillful and as such can overcome some of the negatives typical of having too little cant.

For average surfers it is probably not a good idea (functionally speaking) to follow this pro (fashion) trend. More cant can make a board faster, looser and quicker which are often traits that average surfers will prefer. Holding power and bite, are not often common problems for average surfers riding average waves on crowded weekends.

Hope this helps