to displace or not to displace

I’ve been driving myself crazy trying to decide whether to build a displacement hull or not. I understand how they work and think that they would fit my style of surfing. However it seems to me that the design would be working back from design advancment we’ve made over the years. Iv’e got an old transitional Surfboards Hawaii V bottom, which in my mind could be described as a displacement hull, considering the bottom is bellied and the rails are a pinched 50/50. Every time i ride it, it feels like im ready to go and the thing is still behind me. Seeing as most of my boards are flat bottom slight v in the tail and tucked down rails, i figure im just more used to the speed and have a hard time slowing myself down while riding the V bottom. Not to mention these boards are hard to ride no matter. I guess im just afriad im going to find the same problems if i make a nice displacement hull. I’ve watched the videos and have seen some beautiful surfing on these things and can just imagine myself doing the same. Please help convince me, what is going to make a modern hull ride different from my old vbottom.  Might i be comparing two totally different things, or over thinking it, or am i on the right track and maybe this design is not for me?

A hull has a near flat planing surface along the stringer and will plane higher on that surface and go faster than a full v bottom can ever go. But they need to get up to speed to do that. V bottoms control speed. Hull bottoms beg for it.

1.  Neither is faster or slower.  Depends on wave and surfer.

2.  To speed up RESPONSE in a hull, shallow the V, harden the tail edges, flatten the deck, add template curve, and narrow the board for fast waves.


Thanks for the response guys. I was hoping there would be a reason that they didn’t react the same. Sounds like i’m gonna make me a hull. I suppose if it isn’t for me i can always turn around and sell it to somebody who likes it. Do you have any suggestions on how long i should make the deepest part of the hull on a 8’ ? Where it should start? And aside from the flex in the tail is a s deck really neccessary, meaning do i really need to scoop the nose or can i leave some volume there. Do you like really knifey pinched rails or a little fuller. It’s going to be surfed in all kinds of conditions some point breaks and some beachbreaks. Any other suggestions are much apreciatted.

  OK, let's think this animal through a bit.

  Why ride a hull?  To get drive DTL.  How?  Stand in the MIDDLE of the board, sink the tail turning hard, rebound off your turn!

  Thin tail so you can sink it while standing in the middle of the board.  Thin nose so you can cutback without a huge weight on the nose.

  Thick under your feet, dead center, so you can float and catch more than 2 waves a day.

  Rails..... thick and round for faster moving waves, narrower in width.  Thinner and sharper down for slower moving beachbreak.  With the latter, consider going over 22" wide, or even wider if you're big...which you must be to want an 8' board that forces you to stand in one spot.

  No board is perfect in all conditions, or all surfers. Pick what you want, discard the rest.

Thanks for helping me attack this. I suppose i’m intelligent enough that i should have sat down and figured most of this out on my own, BUT when somebody with EXPERIENCE chimes in it really turns the light bulb on in my head. As far as weight in the nose, what do you think were really talking here. I am a big boy and a little weight in the nose ain’t going to stop me and might add to the glide of the board a bit. I suppose when or if i get comfortable with the board, shorter may be an option. I just figure for someone who rides a lot of longboards and a few shorter boards( as short as 6’) that 8’ is a good size to get the hang of things on. Forces me to stand in one spot? hmmmm. I am an advocate of moving around on the board, and i do see people moving around some on these boards. Maybe a whole lot less than i think they do? Anyhow thank you for the input it definately steered me in the right direction.

One of the biggest design factors is something you haven’t mentioned (or maybe I missed it); what kind of waves are you planning to ride?  Under the right feet anything will work but for the newbee you might want to match board length with the waves you ride.  Short shouldered, steeper beachbreak; go short (7’-), longer walled reef, point or even jetty breaks you can go longer (7’+).  For me, the best all around was around 7’2".  There are as many ways to modify the ride of a hull as anyother surfboard, most already mentioned (width, widepoint, fin setting, rocker, Rocker, and ROCKER) but you can also move the sweetspot by moving the hull (deepest hull) from way up front for point waves to just in front of the fin for beach and short shouldered reefs.

Lastly, before putting planner to foam, find a nice, newer hull  to look at, run you hands over, and drop a straight edge on.  The good ones are very, very subtle but increadibly complex. (and don’t just look at the bottom, the deck rocker is just as important).

Good luck!

Let's see, how to attack this....

Can anything be worse than a shortboard that turns like a long board?  And given the belly nose to widepoint, response already is a touch lagging.  It's not how much foam that's up at the nose that kills cutbacks, it's the balance of the board, which already starts thick at center, thin at tail, usually a big single fin forwards, widepoint about 6" ahead of center, that forces you to ride from the middle of the board.  The belly adds displacement/volume to the front of the board already, so a thin nose that is SLIGHTLY thicker than the nose is the norm.  That's the reason for the camel, or S deck design on single fin boards with big fins forwards.  You need big fins for the wide tail, and moving it forwards is the only way to turn the board.  Thin nose helps.

  Moving around on 8'ers.  Well, certainly you CAN, and the normally wider nose of a hull might encourage this a little.  OTOH, the fin is where the fin is located, and best turning is you standing with your back foot over the leading edge of the swept fin.  Stepping back to normal tri fin position just guarantees you a big spinout.  Those hulls with 13" single fins need the tail rails to help hold in on big strong full body bottom turns.  Add a 13" swept wave fin tuned to your weight and style, and we;'re talking 30' projections to topspeed right off your bottom turns.

Oh, forgot to add.  The thin nose, contrary to conventional thought, actually helps you catch waves sooner.

Sound strange, you being forced BACK to paddle, in effect, using a shorter board.  But it's there.  Thinner nose allows you to tip the nose DOWN the face, middle of paddle, so it's heading downwards, not just horizontally.  A thicker nose allows you forwards when you paddle, but you can't sink it, effectively making it  feel like a battleship when you're going for waves.

Oh, and double concave to panel V was being made in 1968, the predominant bottom shape for big wave guns.  For smaller waves, most shapers I knew thinned out the nose from the bottom, to make single concave, for a thinner stringer, extra lift in slow waves.  That was 1968.

Thanks LeeV i have been looking and researching for probably a year now. The knowledge on this site is incredibly overwhelming to say the least. I completely understand what you are saying. To these boards i might be new but have been surfing for 30 years. I said earlier i ride quite a mix of everything. I do fairly well with really flat longboards on steep beachbreak. I’m pretty sure i capable of handling the board, but something new under your feet is always new. That being said i have ridden boards that just seem to click on the first wave. I’ve read on hear about the foil of the deck causing a sort of slingshot effect when burried, so i get the idea. But i figure untill i get a quite few under my belt i will only come far from what you consider good. Thats how you learn and get better by experience and experimentation. Right? Thanks for queing in on postioning of the sweet spot that was something i was definately looking for.

Thanks LeeD . Never ridden a tri fin in 30 years only single fins and a couple of twins. I dont necessarily want to turn from further up, but maybe add speed to my trim given the conditions. The more you explain the better the picture gets in my head. The Vbottom i was explaining earlier is very similar to the ones Wayne Lynch and McTavish were making around that time. Really wide sort of diamond tailed, bellied through out, and probably about 2inches of V from just in front of the fin back.