"Displacement" Hulls

Continued from above:
Somebody mentioned a longboard that does not go beyond a certain speed. That is due either to the fin and the fin being too far back and not flexing enough. That's why when I custom-ordered my very low rockered classic Pig I ordered the fin box to be placed an inch further forward than normal. I put in a flexible fin with high aspect but a relatively wide base all the way forward in the Box. Another reason the board will not go faster is that it has too much rocker in the tail and the rail in the tail after the end of the fin box is too round and soft but you want release at the very end for speed unless you want to nose ride. When I got the pig I could care less about nose riding. I just wanted to trim on the front third of the board for Speed and stall the board off the tail cuz it's fun. If you have too much rocker and too soft of a rail in the tail it causes the bottom of the board to cavitate with low pressure and that causes a board where you can ride on the nose well but you can't go too fast on a fast wave.

Hope that helps.

njb 17375 prflam

 

P.S. the displacement hulls are hard to ride back side unless you're really used to them because the wide point forward makes it difficult unless that's all you ride. Anything with the Wide Point forward considerably forward is hard on the back side bottom turn. That's why you see Larry bertlemann and buttons ripping hard front side and they also rip back side but if you notice on the backside bottom turn it's weird and they usually kick out. Or switch stance. The rail goes into the water up forward and the tail drags. On a Displacement hull this is alleviated some by the high pinched rails. I also forgot to mention that flat bottom and concave bottom makes the board slower. Let me explain. This makes the board want to go toward the beach straight away from the water of the wave wall but the loaded Dome makes the board want to go down the line and keeps it close to the wall. So the flat bottom board is going toward the beach but then the three or four fins keep it going down the line but because there are so many fins and they are all towed in they drag water like crazy and they make them too small these days so people can slide around and lately people have gone to four Fins because they've added too much concave. They base the concave theory on catamarans. But catamarans go fast on flat smooth straight water not on the curved sucking cylindrical wave and catamarans go fast going straight and have to slow down on curves but a surfer is always curving even when they're going "straight" as they say these days when somebody is going down the line, but they are not going straight they are always curving because you are on a curved surface leaning to one rail. Going straight means going straight with the white water toward the shore perpendicular to the wave line. So all of this does not apply to a wave. These flat concave bottoms with hard edges especially the bunker rails they used to use on some boards are just contradictory 2 riding a wave because you have less control and then you have to put in more fins or make the tail narrow to hold it in with hard edges. The thruster was invented by McCoy because the thrust in a Thruster comes from a wide thick tail not from 3 fins. 3 fins are necessary for somebody who is stubborn and using hard edges when they are not necessary in certain areas along the rail. They slow the reaction and maneuverability of the board. The towed in angle of the side fins slows the board down in a barrel or Fast wave and make it less maneuverable. People will say you're just using the inside fin and the back fin but that's not true unless you are doing an extremely rare on rail extreme turn and that's only for an instant all the fins are in the water dragging. People say this is alleviated by pumping but this does make it go faster but not as fast as a well-made single will go and so the well-made single will beat a section better then these other multi Fin monstrosities. The thick wide tail makes it go faster the softer rail in the tail holds the single in with the hard Edge at the very back of the box right at the end for release. It also auto adjust the speed I mean The McCoys because of the self slotting principle. The bottom Contour harmonizes with other things on the board and that would explain why it's slots itself but I won't go into that as that is a secret. It's actually ridiculously simple I mean the loaded dome by McCoy but complex if you don't know its ultimate cause and correlation. Just think of the shoulder of a wave and then the barrel part and how they relate although this is only a remote clue. If you don't care about maneuverability then The McCoys still the best option as a single fin of course. Get a low rocker version that's longer than normal with a wide thick tail. njb 17375 prflam

 

Or just get an egg shaped with 6040 full thick rails a rolled bottom with a wider tail Than nose and very low rocker and have the hardness or sharp edge at the very back of the fin box and get a flexible Greg Liddle fin with a wide base placed all the way to the front and the fin box Place one inch further forward than normal and don't have the nose or tail foiled out at all but keep it all simple and thick and you will have a fun Cruise board with a rounded tail and nose as this turns and fits the wave easier. If you just like to cruise and go to 5th gear like on a displacement hull but faster get this thing made with the lowest rocker possible about 72 + 18 inch Whitetail and 22 inch wide dead center and 16 or 17 inch wide nose three and one-quarter inch thickness and it will go very well just don't do rolled V Do belly if you want a Point Break like cruising board. It'll go faster because of the fulle rails. Do a slight chime but Blended soft and round no flat spots and it'll go fast on a small gutless point wave and if you go really fast it'll lift up out of the water then go so fast
njb 17375 prflam

 

Jesus Christ, I haven't seen a dissertation that long since Freud discussed The Ego and The Id.

Yeah, I didn't read much of that one, either.

Next time, try starting with a simple "herro" thread, Tolstoy.

 

Yeah, that's like the verbosity of the old Emass and zach619 all rolled into one without the hip surf lingo.

 

And no paragraphs, nice troll job lol

 

Finally someone more boring than me!

 

This is so flagrantly moronic it is beyond words.
So, then, if a design is good or bad depends on skill or talent of a surfer?? Really??
NEXT DISCUSSANT, PLEASE!!

btw, I read that one line and it said "do not go any further"......

 

I wish there were more threads like this. Barry Snyder and Barry Cuda in the same thread... now I have seen it all.

LBCrew your explanations are really interesting.

 

Geez those Pio posts look like word finds. I think I found "Roy Stuart Loves Orange" on an upside down diagonal.

Anyhoo, after reading this I had a question. I have a noserider. It's a pretty interesting take on the shape from a local guy. It's 9x23x3 with a wide round nose and wide tail. It's wide everywhere. It's tradtional as in pretty flat rocker until the tail, which is square. I don't think the rail is 50/50 though more of a 60/40 and is a little pinched. But it has a bellied bottom with a concave ( not a tear drop) up at the nose.

It's a great board. more performance than I thought it would be on turns at the tail which I attributed to the rails, but I've never been so comfortable at the tip. On a good full long board wave and when I set up right for a nose ride with a faded pivot turn and all it just what it should be. But sometimes on a longer glassy wall and I'm shooting a section it feels incredibly fast. like it hits another gear. Like a bonzer gear. Instead of some easy breezy time at the tip of a slower board it's a cheater five on a missile.

so my question, would the concave up front with heavy tail rocker and the belly and how the rails are shaped all add up to that lifting force you are talking about? could I be riding just a the apex at the stringer? I'm not surfing it in big or powerful waves. Just liners really almost always beach break.

 

Not really sure, PeaJay... but maybe this might explain some of it:

Nose concaves create both lift and drag simultaneously. The part of the concave that creates the most lift is the aft edge of the concave, where water flowing through the concave hits the angular, downward surface around the "rim" of the concave. The water is deflected downward by this edge, and the board is deflected up (basic Newtonian mechanics). That's the lift part.

The drag part comes from the fact that the irregular surface of the bottom in the nose creates form drag, slowing the board down, overall. This is even more pronounced if the concave edge is crisp, as opposed to blended. A crisp edge actually adds a bit of turbulent drag into the equation. All this drag helps slow you down and keep you in the pocket, and it all works in combination with the soft rails (water wraps around soft rails... releases from edged or pinched rails) and lots of tail kick (Coanda effect creating low pressure under the tail, or "suction" that holds the tail down).

So... while your board is responding to the steeper wave face of your glassy little peelers by accelerating, as it should, the trick might be to get to the nose faster, or earlier, in order to get that lift/drag thing working. Noseriding beachbreak waves requires quick feet. The other thing is to do more of a stall pivot bottom turn instead of a fade type turn. A really dramatic "soul arch" bottom turn both looks stylish, feels good, and is highly functional, in that it slows you down, and puts you right into the pocket almost automatically.

If your board has belly all the way through the middle, like a lot of the traditional longboards of the '60s did, then that might be working against you in terms of staying in the pocket, just as you suggested in your post. I prefer a flat section through the middle, between the concave under the nose and the rolled vee in the tail. It helps to sort of neutralize the ride a bit... not too much hull effect, and not too much concave lift effect.

 

LB your something else man. Truly. I tell you why.

I got 2 surfs in yesterday and this morning. One before your post and one after. I got a wave yesterday afternoon that started out as a bowly right. I was at the tail and hooked a backside top turn under the lip. It was more of a short board turn if you get my drift. I came down and turned left to ride the inside that way walking the board through the foam to be at the nose at the pocket. I felt a significant zip of speed after the turn that I'm thinking was from pushing the fin hard and flexing it. That zip pushed me out and I ended in that crouched cheater five and racing through. I left the best part of the wave behind me as I cruised out onto the shoulder. That turn was more "drastic" then my faded bottom turns but It made me start thinking about how I'm going about things. Then I read your post.


You hit the nail on the head explaining my board. That's exactly what it is. and when you said to drop the fade turn and do a pivot that made sense too. I definitely don't do that. Faded turns feel good. But getting to the nose faster? That one had me thinking. I think I'm pretty quick to get up there but I went surfing this morning determined to pivot and walk up faster. Good waves again same as yesterday only cleaner with a longer wall. My first wave was a good one and I pivoted and walked right up. Right into a crouched cheater 5 and flew down the line same as before. But then it hit me like a brick. I'm not getting to the nose fast. I'm attempting to get to the nose fast. When the wave is really standing tall I'm stopping before the nose. Call it hesitation or chickening out but that's what I've been doing. Like forever. Playing safe. I'm thinking that when I'm in that crouch my weight is not on the concave at all. Just my front leg. and maybe that isn't enough? So I paddled back out and caught another right away. Good waves today that were consistent and coming in sets. I pivoted. I walked. I hesitated for a second after putting my front foot over. I started to crouch as the wall stretched out but forced myself to stand tall and put my other foot over. My two big toes were touching. And everything slowed down! Perfect trim, right in the pocket all the way to the sand where I got picked up and slammed into the dirt. I'm pretty psyched about it. I caught a bunch more with mixed results. I lost my board more than ever. I can't fall on it if it isn't in front of me and if that last step forward was hard the first step back was a disaster. But whatever i'll figure it out.

Any way thanks dude you're one in ten million. You got a dude who's been surfing awhile change his swing.

 

Peace and tip time, brother!