what is the general rule when pairing a fin with a board? or, is it just general preference?
there’s a wealth of fins out there, and it gets kind of confusing when it comes time to decide. i’m not in the market for a new fin right now, but if it ever arises, i’d like to know what size i should get correlating to my board. and i’m sure some other people are curious to the answer.
For longboard fins a good rule of thumb is board length, ie 9 ft board 9 in fin. but this varies based on fin base, area, rake. ect. For Thruster/quad its more about your weight. more area will give you more hold. a larger base will give you more drive in a bottom turn. the more rake a fin has the more drawn out the turns are, the more upright the more pivoty a fin feels.
And for tris/quads also have to factor board/tail width, rocker, fin placement - more clustered back or more spread open and forward…lotta ways to skin that cat…so best to have a good selection of quality fins and see what works best with that particular shape…
example - have a clustered squash that works best with Occy fins, and a spread RP that works best with Simon Anderson fins…
In my opinion and (limited) experience, determining the right depth has to do with the tail width an fin placement. Base and how much sweep depends on the waves you surf, and how long you want your turning radius to be. good luck
I have found that I surf bigger fins in smaller boards than what is generally accepted and surf smaller fins in bigger boards than is generally acceptd.
So, I got a set of probox GT quads that I ride with my 5’10" simm[ish] board. Conversely, I like a 7 3/4" swoop on my 9’ longboard… Go figure.
Fin sizes for boards that are singles or 2 + 1 are really important
to making the design you have work well. A general rule of thumb is
that board length determines fin size. Eg; 7' board, 7" fin, 9' board, 9" fin.
A 2 + 1 should be looked at as a derivative of fin area. With a 3.5" side fin,
a 9' board would be outfited with a 8' fin or less. Larger side fins would
warent a reduction of center fin size. As fin sizes reduce in a 2 + 1, fin foil
becomes important.
Thrusters and quads are another matter, and the fin area vrs. surfer weight/strength
becomes important. Fin dots are based on a base length of 4.5" for the sides. Sizes
go up or down based on the requirements of the surfer. I go with bigger fins on comp
boards so that they generate more spray, less if there is more tail blows, airs, etc. in the
surfers palate, etc... As a custom shaper, fins have a lot to due with customer
satisfaction for a particular design. There are lots of variables going on here
so you get the general idea! Hope this helps!
tail area :fin area is how I work it., it obviosly varies depending on design and surfer size and waves…
thanks for the knowledge everyone. surfteach, that’s some crucial information right there! hit the nail on the head! hahah
I’d say this it pretty close to how I see it. Don’t matter how long the board is, if the board and tail are wider you’ll need more fin(s).
10’ single fin gun doesn’t mean you use a 10" fin. 6’ extra wide round tail won’t work with a single 6" fin.
All of my single fins (not boards) were 9". I had a variety of designs, and they were used in boards from 6’ to 8’. I think the modern board uses a wider outline with the wide point near center or even back of center. That works better with multiple fins. More fins means you can use use smaller fins.
I will add to the list of fin depth vs tail area. Wide tail? Deeper fin. This is for singles, only.
I scale like this …11" tail = 7" fin, then add 1/2" for every inch of tail width. YMMV
Guys, From direct experience, I've used 6 and 7 inch deep fins on 10 foot plus big wave guns with great success. In Dec.1969 Doc White rode 30 foot Makaha all day on a 10' 6'' x 23'' gun with a 7 inch deep fin. Wisdom of the day was that 23 inch wide guns would not work, and ''spin out'' in really large waves. So much of what people'' know'', just isn't so. Now, all that said, I don't think there is ever any reason to run a fin greater than 8 inches deep. The answer lies in the placement, foil, angle of incidence,total surface area, and rake of the fin.
Mr. Thrailkill, do you see merit in a flex fin a la Greenough? I can't seem to get away from them. I like turning the board from the center on a rail rather than pivot and the extra depth pays off in my experiences.
[quote="$1"]
Mr. Thrailkill, do you see merit in a flex fin a la Greenough?
[/quote]
No. Apoligies to lovers of the mythical twang. (What you feel is the lag in response time.)
Stiff is better?
[quote="$1"]
Stiff is better?
[/quote]
Yes, in both my opinion, and in my experience.
[quote="$1"]
[quote="$1"]
Mr. Thrailkill, do you see merit in a flex fin a la Greenough?
[/quote]
No. Apoligies to lovers of the mythical twang. (What you feel is the lag in response time.)
[/quote]
I like how the "mythical twang" feels in weaker surf...In bigger surf, I do not like it
Thanks for the replies Mr. Thrailkill. Will investigate further. I want to try your double center fin set up.
I have 2 Greenough stage 4a fins and I love them. I can’t say that I can feel any flex, but I like that they have a wide base. I get a lot of drive out of them. I use a 9" on all my single fin boards, and about a year or so ago I got a 7.5" version. I use that on my 2 + 1 boards.
I have a Liddle 9", but I’m not using it for the flexing.
I have a 10" or 11" fin for my big 10’ board that I used for tandem with my kids when they were small.
The board in the photo has a 9" cutaway and it worked great. I cold get way over on the rail without sliding.
I use Liddle fins also and really like the 9". Maybe I'm so used to them that others feel wierd when I try them. It's not the "mythical twang" that I feel but like Sharkcountry, "I could get way out over the rail without sliding". I think that is the feeling I'm looking for.