cuda, That is a nice board, not sure your single fin idea with a flex fin would be a good idea. Your swallows are deep which in some of my past experineces don't work well has a single fin. Tri fin set-up not something I would think about, just me though. Twin fin first choice then Quad and maybe a Twinzer option would be the direction for that board.
I would have to agree which John, your back fins have 2 things I think might be working against you. 1.) they are to big 2.) The rear fins look to be double foil which is the main thing right off the bat that would give you the tracky feel and cutbacks to much of a chore, along with being to far apart.
Taking the fins off is a easy job, I am doing a Keel Twin fin glas-on conversion now into a Quad for a friend from Hawaii on a Bushman Board. When I get done will be happy to post pics.
they are 3.75 tall to 4.5 for the fronts? would you make them smaller? if so by about how much?
I think I’ll stick with the quad platform - so here is waht I’m thinking i’ll rmove the rear fins and lose the inside foil and re-set them up stepped in toward the stringer about an inch (McKee’s table) from the original position - this sounds clean and doable and keeps the board as intended.
I personally think that double foils on back fins of the same size, shape and area give better pivot and less grip than single foils whose inside faces give more drive and hold.
For point breaks, flat faces for ‘off the bottom’ and double foils for off the top. . Asymmetrical mixes. Unfortunately you can’t test so easy with glass-ons… this though is more beneficial on short-boards.
With long boards you can get your back foot behind the quad fins for leverage so the double or single foil is not so critical except if you never get on the tail. It is noticeable though. Size and flex are also adjusters…
Moving the double foils away from the rail with give them less hold than before (which was too much anyway) but when the board is flattened off, it will have the same hold and better forward directional qualities.
You probably found this long-board a bitch to swing around after running the wall. The fins penetrating the wall are saying… “tail move down and nose go up the face”. For the redirection down the face, by the time the lower side fins enter to say… “tail, move up the face and nose come down” you’ve already exhausted the body gyrations and find your board is crabbing. Full rail to rail surfing can help, but the more centralised tail fins work more like the single or ‘thruster’ tail fin in straightening the board up and enter into the wave face on the lower side much earlier in the turn transition. Makes them much easier to ride and more predictable.
Bruce...I used your formula on a 9-6 Mod Longboard with LokBox fins and I find that it performs much better (turns easier) in "juicier" or more powerful surf than in slower, mushier surf. Is this true of LB quads in general (assuming proper integration of outline, tail rocker and fin placement)? Secondly, I've found that back-foot placement over the fin array is essential for turning this board. Again, is this a quality of LB Quads or have I screwed-up something on this particular board? I first used a set of Rainbow LokBox AK4 Quad (with rears 80/20 foiled), but switch to LBX1 front and LBXM3.8 rears (80/20 foiled) that gave me a shorter rear fin and allowed me to compress the fin array. This helped a lot. Then I read here on Sways (tomatdaum & lokbox) that a set of LBXT-1 (5-3/8" Twin) in front and the LBXM (3.8" 80/20) trailers are the recommended fins for LB Quads. Wouldn't the larger front fins cause more tracking? I'm seriously considering installing a center-fin box and going single or 2+1 with this board, but I love the way it holds in on steep faces, which is the board's intended use.
I’ll have to study up on the Lok-box fin sizes… But if the board is stiff in small waves, often reducing total fin area will free the board up. Also having a flexier rear fin than front fin gives a more single-fin flex recoil feel.
It may be that the fin direction you require has more toe-in.
The directions I have in the formula are for a bit of an all round feel. Some FCS and other brand fins have more toe-in than others and you may find, that customising the fin angles will loosen it up.
In a future board, you may also like to cluster up the mix a bit more to give it a bit more pivot, but your experiment with the more upright rear fins was good and also has a similar effect.
More toe-in will help the tail to round out more in the turn. The advantage of having the back fins closer as in the formula, is that if you choose to have more toe-in, the crab effect, or stuck on one tack in the lip effect I mentioned earlier above with the body gyrations, is minimised.
A larger front fin than rear fin will give a pivot effect but with all the rail length, with a quad, in smaller waves, a lot of fin is not necessary so you can scale down the total area.
I (80 kg/176 lb) normally use the equivalent of a M3 fin on the front and an G1000 or M2 fin on the back and the board still hangs in in large surf but I can swish it around in the small stuff.
Less fin area also means less need for a heavy back foot as once the turn is initiated, momentum and drift will help the tail to come around. When the fins are larger, foot position is more critical and every part of fin positioning is more highlighted and noticeable.
I won’t mention the fin system that allows you play around with all the angles on the spot… But Dean Geraghty might.
I have been using a set up like this in my 9’er. When I had a more balanced, normal? set up I was OK with the board, just did not have the “slinky snap” I wanted in my longboard. Reached into my mystery fin bag and figured what the heck. WORKS SUPER GOOD!!
I agree with big fin smaller fin deal. I am also a fan of a flexier trailing fin/s. The larger fins are 5.5" and really flexy at the tips. the smaller ones are 3.50.
