Early shortboard planshape

The coffin like planshape of the very early shortboard designs with the wide point well ahead of center and the rail behind that to the tail not too curvy almost strait. I notice this even in very short small wave boards. What are the performance differences, Pro or con in relation to shortboard planshapes of today and why did it disapear from mainstream? Does this plan shape work better with a single fin than one with more hip? Is it better with flatter rocker as opposed to modern rocker? Thanks, CAMPBELL.

It’s funny. When we used single fins, tails got narrower and narrower. The reason was to put the fin closer to the tail rail. Single fins try to release in extreme turns and on walls. Single fins are the reason why early shortboards had narrow tails and forward offset. Then we started using three fins with thrusters close to the rails. So did tails get wider again? No, they continued getting narrower. Why? Maybe somebody can tell us. Since we can handle the tail release thing, I like a little wider, curved tail. Think of the turn as a cone reaching deep into the water. The curved tail rail reaches into the water and provides a pivot for the rocker to arc around. By the way, this turn scenario brings water curving off the tail rail (in relation to the board), not shooting straight off the tail. You might want to rethink that next channeled board.>>> The coffin like planshape of the very early shortboard designs with the > wide point well ahead of center and the rail behind that to the tail not > too curvy almost strait. I notice this even in very short small wave > boards. What are the performance differences, Pro or con in relation to > shortboard planshapes of today and why did it disapear from mainstream? > Does this plan shape work better with a single fin than one with more hip? > Is it better with flatter rocker as opposed to modern rocker? Thanks, > CAMPBELL.

It’s funny. When we used single fins, tails got narrower and narrower. The > reason was to put the fin closer to the tail rail. Single fins try to > release in extreme turns and on walls. Single fins are the reason why > early shortboards had narrow tails and forward offset.>>> Then we started using three fins with thrusters close to the rails. So did > tails get wider again? No, they continued getting narrower. Why? Maybe > somebody can tell us.>>> Since we can handle the tail release thing, I like a little wider, curved > tail. Think of the turn as a cone reaching deep into the water. The curved > tail rail reaches into the water and provides a pivot for the rocker to > arc around.>>> By the way, this turn scenario brings water curving off the tail rail (in > relation to the board), not shooting straight off the tail. You might want > to rethink that next channeled board. If I build a single finner with this old style planshape, without wings, how wide do you suppose I can go max with this tail? If I make the tail a swallow can I go wider still…how much?

Dude!.. Some shortboard shaper needs to step in here. Wings? You mean the outline break behind thruster fins, right? I thought those were for use with thruster fins. The thrusters dump across the wings. Wings allow parallel shortboard mid-board rails for trimming and carving, while maintaining a narrow stern, for dropins and snapbacks… when you’re on the tail. My commercial shortboard has them and I think they do very little. A swallow tail provides stern control on a wider stern. I’ve never ridden one. In a fish you would combine a swallow tail with very little tail rocker for low-power speed. Each tail point requires a thruster. A swallow tail would break loose and act squirrely with a single fin. If you narrow the swallow tail, wouldn’t you negate the reason for the swallow tail? A single fin board is carvey, not skatey. To turn well it requires lots of rocker. Maybe there’s more science here than I know. I think functional single-fin tail width depends in the overall shape. If you want a 22" wide 7-0 board with a narrow stern, you could go with a 15.5" tail. Lengthen it into a longboard, and a 14.5" tail is pretty wide. What kind of board do you want? What kind of waves/ break are you going for? How do you want to ride it? Herb, Tom, Jim, Steve?

Dude!.. Some shortboard shaper needs to step in here.>>> Wings? You mean the outline break behind thruster fins, right? I thought > those were for use with thruster fins. The thrusters dump across the > wings. Wings allow parallel shortboard mid-board rails for trimming and > carving, while maintaining a narrow stern, for dropins and snapbacks… > when you’re on the tail. My commercial shortboard has them and I think > they do very little.>>> A swallow tail provides stern control on a wider stern. I’ve never ridden > one. In a fish you would combine a swallow tail with very little tail > rocker for low-power speed. Each tail point requires a thruster. A swallow > tail would break loose and act squirrely with a single fin. If you narrow > the swallow tail, wouldn’t you negate the reason for the swallow tail?>>> A single fin board is carvey, not skatey. To turn well it requires lots of > rocker.>>> Maybe there’s more science here than I know. I think functional single-fin > tail width depends in the overall shape. If you want a 22" wide 7-0 > board with a narrow stern, you could go with a 15.5" tail. Lengthen > it into a longboard, and a 14.5" tail is pretty wide.>>> What kind of board do you want? What kind of waves/ break are you going > for? How do you want to ride it?>>> Herb, Tom, Jim, Steve? I’m looking at photos of early shortboards (because I didn’t surf em, was’nt there) and I’m seeing a lot of variation to tail designs in them. I guess there was a lot of experimentation going on back then. There were some single finners with apparently quite wide squash and diamond tails. Then some had wings with a very compact, narrow swallow tail following the wings. So in these cases evidently they weren’t using the swallow the same as a wide tailed fish swallow is. My understanding is that the two pins of a swallow allow more hold-in in a wider tail so you get the benifit of width without it tending to slide out. With a diamond or squash at some point as you increase tail width a single fin will begin to fail at controling it. So then you go to multi fins to regain. If a swallow’s two pins by themselves improve control then would they not allow the single fin tail width to be pushed out a little farther than a square or squash or diamond? If that’s the case then it must have it’s width threshold also where the lone fin fails. This board will be for small waves with the widest possible tail it can have without multi-fins. I just want it to be a single. Trying to get a feel for what that width threshold might be and what tail type will put it there without having spin outs. Another consideration will be the fin dimensions and design. It looks like these ideas were mulled over and tested in the early 70’s judging from the variation I see in these boards. There’s nothing new under the sun here, I figure someone knows.

If you go deep with the swallow you can get away with more.I have built functional singlefin swallowtails as wide as 16.5"tail widths, with a tip to tip of 9",but it does require a health 9"+++ fin.Herb.

If you go deep with the swallow you can get away with more.I have built > functional singlefin swallowtails as wide as 16.5"tail widths, with a > tip to tip of 9",but it does require a health 9"+++ fin.Herb. Thanks for those numbers Herb, that gives me something to work from. Thanks Noodle for your input. CAMPBELL.