You all are so extremely knowledgeable, I hate to ask such a rookie question. However, I will anyway. Would somebody mind briefly explaning the benefits of a single fin v. a 2+1 setup on a longboard. I have a 9’0" with a 2+1 and am wondering what riding it as a single would do for me (i.e. pros and cons). Also what size single wold be best. I’m thinking a 9 incher. A short primer on fin setups would be great. Thanks so much.
2+1 are primarily used to increase holding ability of your board through steeper angles of turns. As tail widths increase and buoyancy increases at the rails a single center fin needs to be longer and longer to retain holding power as the board is brought on rail. If you place a small fin out towards the rail this increases holding power at steeper angles without extra center fin length. If a center fin gets to long and does not have sufficient rigidity you going to loose holding power from tip flex. So, depending upon your tail configuration and how steep you like to turn will have great significance on how removing those side bites will feel. Positive side in small mushy waves there would be slightly less drag from removing the side bites.
Good explanation! The biggest practical difference for me: With only a single fin the board paddles into a wave quicker and easier. It accelerates while I pop up. On steep waves I can have dropped too far down by the time I get popped up. The pit is passing me by before I can turn. With my side bites in, paddling into a wave is harder and slower. On steeper waves the board moves slower while I pop up. I’m still in the lip in time to turn from the top.>>> 2+1 are primarily used to increase holding ability of your board through > steeper angles of turns. As tail widths increase and buoyancy increases at > the rails a single center fin needs to be longer and longer to retain > holding power as the board is brought on rail. If you place a small fin > out towards the rail this increases holding power at steeper angles > without extra center fin length. If a center fin gets to long and does not > have sufficient rigidity you going to loose holding power from tip flex. > So, depending upon your tail configuration and how steep you like to turn > will have great significance on how removing those side bites will feel. > Positive side in small mushy waves there would be slightly less drag from > removing the side bites.
For me, the main difference is simply in the feel of the turn. With sidebites, any pressure on your rail is going to dig the side fins into the face and you’ll get a quick “grab-and-carve” type of turn. I prefer a single fin because it gives you a pivot-type of turn. You actually feel a pivot/fulcrum point when you step back and turn, and it’s a much smoother feel than the “grab/bite” of 2+1. It’s like the difference between a Caddy and an import. Smooth and relaxed with single, quick and sharp with 2+1. I felt a little more free after removing my side fins. Some of that, I’m sure, has much to do with the drag-factor already mentioned.
Thanks a lot guys, that makes a lot of sense. As for fin size, does 9" on a 9’ board make sense? Also what is the advantage of these cutout fins or squirl tail type fins? Thanks again.
Thanks a lot guys, that makes a lot of sense. As for fin size, does > 9" on a 9’ board make sense? I have noticed that the coincidence of feet-to-inches works for me. A 9" fin on a 9’ board will work great for you, much better than anything shorter (depending on what you want out of your rides, of course). You can even go longer. I have a 10-inch Wingnut fin on my 9’6 (box fin). I even use this 10-incher on my 9’3 and I love the way it feels. I never have to worry about it “popping out” while doing hard bottom turns on steep waves. I also recently made a bigger fin, like 11 inches, and put that on the same board (the 9-6). I love the way it rides with the big fin, although some fine tuning of the fin is necessary. The big fins give me a nice, stable ride, and I have no problems turning, especially when I move it to the front of the box. Longer fins also help A LOT with tip time. The only caution to think of is LOW TIDE and kelp. Try to get in touch with Gene Cooper (www.cooperfishsurfboards.com) and ask him about big fins. I’m also sure Paul Jensen (check out the forum) has some valuable things to say on this topic.
Here are some of the basic concepts of fin set-ups and how they affect performance. Depending on the size, shape and placement of a single fin on your board, you would probably have a looser-feeling, yet stable, board that would allow you up to do those great left-go-right turns at take-off that are more difficult with a tri-fin. The “Narrow Base - Thick Base - Fully Foiled Fin” is a smooth, loose-feeling fin, that turns tight and releases well. With a fully foiled fin you can use a deeper fin with out the drag you would feel with a conventional fin. The reason is that a foiled fin releases water efficiently and a “flat” fin creates turbulence drag. My personal favorite is: depth 10",rake 10.5", width of base 5", Thickness at base 1.125". It has an 1/8" glass core, laminated to that is 1/2" Baltic birch plywood on both sides, foiled, glassed. The theory behind the “Thick Base - Fully Foiled Fin”… George Greenough had perfected the high-aspect, laminar flow fin, a development, which made him literally the fastest man in the water. The key lay in constructing a fin which could harness the wave’s energy without generating drag-inducing turbulence along the trailing edge of the fin as it moved through the water…Laminar flow basically is over a very narrow range. Water only goes back an inch and a quarter or so before breaking into turbulent flow. So the fin must be narrow. Look at any high-performance fish and you’ll see my fin is basically the same - it’s the same plan and foil shape as a large tuna…you’ll notice their tail is very narrow and quite high. With that kind of fin by the time the turbulence shows up in the water the fin has already left it behind. Hence no turbulence to affect performance. Another great fin is a “Liddle Flex Fin”. Greg Liddle’s theory “I cannot emphasize enough how important it is to have a flexible fin or fins. The fin allows the board to behave appropriately. To trim at high speed with little effort. To maneuver smoothly and particularly to release during down the line high speed turns. A rigid fin with the inappropriate foil will not make this happen with these boards. The board will pivot awkwardly and die out of a turn with no forward acceleration. It will feel wrong to the initiated.” “It is essential that the fin have this particular type of flex, not a soft bending over flex, but a high tension flex that bends concave and gradually into the base of the fin. It lets power on and off even and smoothly resulting in a high speed and flowing style of surfing.” Another good fin is the “Wingnut Long-Rake” fin made by Rainbow Fin Co. is a fairly deep (10") fin medium stiff with plenty of rake and not too much tip. It’s a good fin for longer, driving turns. Smooth sweeping turns and extended trim are more difficult with many of the contemporary multi-fin boards. These boards often have a “stage-y” feel that is more suited to those who prefer “triple-pump” bottom-turns. The tri-fin set-up is only “faster” if it is pumped or rapidly turned from rail to rail. In straight-line trim the tri-fins are just so much drag. Some of the more progressive tri-fins have other design features, such as accelerated rocker, thin volume or narrow planshape that adds more drag, and requires even more energy from the surfer’s to fully use the leverage and projection of the tri-fin design. A “2 + 1”, or a “single fin with training wheels”, is a larger single fin in a center box, supplemented with smaller, Thruster-like side fins set on the rails. The most common set-up is a center fin box holding a 6" to 8" single fin. Side fins are sometimes glassed-on, but FCS plugs are common. The center fin is sometimes placed further up in the box, serving to narrow the “wheelbase” of the combined fins to give the board a looser rail-to-rail feeling. To summarize, the single-fin seems best suited to those who want to trim, glide and perform smooth sweeping turns. A single fin is stable yet pivotal. If you enjoy more energetic surfing, go for a multi-fin, with the “2 + 1” being a reliable compromise. I hope this has been of some help, and that you enjoy experimenting…
The deep high aspect ratio, deep dredging flex fin is a good performer. I rode one for many years. In slow conditions however, it bogged down. It put lots of pressure on the entry rails making slow turns on the rail difficult. I would have to back weight and crank to turn. Long ago I built a model stunt plane using a high aspect wing. It turned tighter loops than anything I had ever flown, and maintained control through slower flight. The thick front profile of high aspect fins creates more drag than normal in a straight line. But when turning, flow stays in contact with the fin surface. A guy calling himself Surfdog passed on a tip from Peter Mel. Sand the ends of these deep fins thin to make them more flexible. I plan to do this, but haven’t gotten around to it. It would eliminate the added rail pressure at slow speed.