stubby fin rule

what’s a good rule of thumb for fin size on a short 2 ÷ 1 stub?  I feel over-finned at  8" on my 6’4"  - it has a 16" nose and 15 1/2" tail with 3.25" side bites

it seems in the back of my mind the old single fin rule was one inch of fin for every one foot of board

what do you stubbers think?!

I've got a 6'6" and use a 6.5" centre fin...feels just right...I have a 6'8" single fin that has a full template and have been using an 8" flex fin in it but like you feel over finned - certainly when it's bigger/more critical waves.



Try a 6 or 6 1/2" cutaway…1" of fin per foot of board seems excessive with side bites. Plus, by that formula, you’re over finned on a 6-4.

I ride a 9’ with 2+1 with a 6 1/2 " cutaway center fin and 3 1/4" sides up to head high + and like the looseness.

But maybe that’s just me…

Fiberglass Supply has 6" cutaways on sale now for cheap…worth a shot…you can never have too many fins…


o.k. thirdshade - sounds logical - how big are the side bites on your 6’6"?  


I’ve looked at Liddles & Finelines - they have like 9 inch center fins - ?!


what's a good rule of thumb for fin size on a short 2 ÷ 1 stub?  I feel over-finned at  8" on my 6'4"  - it has a 16" nose and 15 1/2" tail with 3.25" side bites

it seems in the back of my mind the old single fin rule was one inch of fin for every one foot of board

what do you stubbers think?!



There are no rules......Sounds like you're a little over finned...did you try it as a single with the 8" fin....

I use FCS GL side bites...standard longboard sidebits.

The bigger fin in singlefin is fine until I'm going real quick - big or real critical wave...then I can feel myself fighting it...OK if I'm trimming from further up the board but if I try a harder turn off the tail I feel like I'm going to be thrown off...undoubtedly most of my problem is poor technique...but that's another story!



Yep! - as a single fin it is super sweet - I’ve had LITERALLY magic waves on one fin in the perfect spot, but overall less hold on the average days, So, the classic compromise is to go 2 + 1 and get the right combo.


I’ve gone smaller on the middle fin, down to 5.5, but then I lose the good old singlefin feeling.


soooo…, 6.5 + side bites, what do you think?

chop your side fins in half and leave the 8" in there. Any good-feeling singlefin with two 3.75" side fins is going to loose almost all of its “singlefinny”-ness IMO; use as little side fin as possible if you liked how it felt as a single!

well, SG, I may just try that…  


I had a little smaller sidebites at one point, but not that small -


how small? 1 5/8ths?! really?


anyway, that would be cheaper than buying a new fin!


i like around 2 1/4" with a 1 1/2" base or so

yep ..... i'm with surferguy80 !


  i like riding them as single fins too, though.

Get rid of the side bites and go single with a True Ames (or similar profile) 6.5" California Classic. Experiment with the placement in the box. I ride with the fin up front on small days and further back on bigger days. Save the side bites for nearly vertical days or ride a thruster. FCS used to make a thruster to long box fin converter. Be sure to drill through side of tabs and fin for set screws. The placment they have actually pushes the fin out of the box. Now you could ride single, 2+1, twin, or thruster. All this is assuming your sides are in fin boxes not glassed on like the old boards in the 80s. This thing was originally a thruster or 2+1 but the guy I bought it from took off the sides and maybe put in a box. There are reference lines where the sides used to be. I never found the need to ride this board as anything other than single. To be fair though on gnarly days that I’m going to be doing a lot of ducking or riding choppy waves I use a thinner thruster. I don’t want to bob around like a cork or come up in the middle of the wave and go over the falls backward!

how tall are you and how much do you weigh?

i used to ride a 6’4 Mp3 fineline hull with an 8" worked fine with or without sidebites, im 6’1 - 185


sold it to a friend who most likely is at least 20 pounds lighter and a tad shorter, pretty sure he would feel overfinned on it with an 8" but now im curious,


good luck

I use a 9" greenough stage 4a on my 5-11 stubbie. Even with that big fin, there were over head days that I felt the board needed more. I added 2 side boxes, and have tried the board as a 2 +1, as a twin with a small trailer and now I have it setup as a thruster. I haven’t used it as a thruster, but based on the last time I used it, it should work really well. 

I just converted another 70’s style 6-4 diamond tail to a McKee quattro from a large single box. I have it setup as a thruster, but I can switch to quad or 5fin if I want.

This picture is the 5-11 board with the stage 4a and 2 little twinzer sidebites. I just added the extra 4 boxes to the green board. This shot is when it was a single fin.


I had the same problem on my 6'6" egg, I had a 7 1/2 inch TK flex by rainbow fins and side bites.  I removed the side bites and love it.  I also have a 6" fin that felt over finned with the side bites in, so I trimmed the side bites using a dremmel to 1/2 the size, round like bonzer side bites.  It works perfectly and now I leave them in if I switch to the 7 1/2 fin also.  Cuttin to the chase: trim your side bites down and it will work waaaaaaaaaaaaaay better.

also remember that sidebites are essentially adding base width to your fin setup; therefore, use a fin with less base when using sides; the surface area of your side fins plus your center fin should add up to the same number as your single fin alone would…if that makes sense; youre just distributing your ‘fin’ to different areas for more hold and different drive/response!

i’ve used an extremely narrow based 9" with 2 1/2" sidebites on a 6’1 with a very wide tail and it felt fantastic!

hey N Chap - I’m 5’7" and 165 - so yeah, it could be a size issue…

this is a bunch of good advice from everyone - I’m using a 7.5 TK flex, and it is almost perfect - but sometimes it has this kind of see-saw out of balance  effect, but w/ the bigger sidebites it’s more stable

I’m really committed to the flexfin though - the snpa out of bottom turns is practically the whole reason I ride this board! 

I like the idea of little half round sidebites - template ideas?  Maybe just shrink a keel fin template?

....on a related [VERY small board] topic ,


  i was watching some 1968 footage of greenough [anyone know how tall he is , please?]...the film is called 'Children of the Sun' , if you can get hold of it...


 he was  on a supposedly 4'11 kneeboard , at noosa and moffats, in queensland


  his fin was HUGE , and flexi


  watching him , in slow motion , on ONE wave , he bottom-turned so HARD , then cutback so hard [it's a right] , that he literally only had the fin tip in the water. it looked like a grab-rail bert thruster , or  a 'Buttons' at V-land manouevre.


  So ,  i could see the point of the big flexi fin on a small board , WHEN i saw that footage ! [i'd never REAALLLY got my head around the idea , in the past ]. i , however, do not have the low centre of gravity , power in the waves [ or perhaps it's  just the lack of the raw ability/ freakish talent of george , slater , fanning , pancho, curren etc!]


  so , i guess i just throw that in there as a "keep my mind open to trying all sorts of stuff " thought


  this is a good thread , thanks for the photos and thoughts / experience , shark county! [i hope brother bernie chimes in here , too ?!]


..... the 80's channel islands  thruster to single conversion looks interesting , too .....


with me far , the biggest fin i have used consistently on my 5'10 to 6'1 stubbies has been a 5" base , 8" deep polycarbonate ....but , i DO have a 9" deep , 5" base , 3" rake , black fibreglass finbox fin remodel , which i need to finish and get in the orange stub ....


    keep 'em coming , i'm a stub fan !


 cheers !




p.s. - wasn't Dave Parmenter's 'Stub Vector' model set up for a '2+1' , and / or a 'widowmaker' option , too, from memory ??

Check out this thread for 2 + 1 set ups and you’ll find heaps of pics of sidebites.

The little sidebites in the board I posted pics of would be worth trying.

Gave a set to my mate to try in his 7’2" egg yesterday and he loved them.

Was using a 6.5" fin with GL sidebites and by using the smaller sidebites he was able to move the fin back in the box and he thought the board released off the top much better.

I think i may have posted pics of the board I’m talking about on that thread!  and hey, chipfins - that was super insightful about GG’s style- when you really lay it over on the side - )and not coincidentally engage the rail) - that’s when that longer flex-fin becomes useful.  When I saw “State of S” a couple years ago, I was blown away by how torqued Greenough get those urns!  No wonder we all want to do THAT!

I talked to one of the guys from the local fin co. - he suggested smaller bites (like what SG80 said), but also soften up my center fin.

another ? comes to mind - do many of you 2 + 1 riders have all 3 fins lined up, or are most going with sidebites forward?