I have been trying to educate myself about hulls, as I'd like to attempt to build one someday. Found this interesting excerpt...
...what exactly makes hulls worth riding?What differentiates them from McThruster?
“The simplest analogy to draw is: There's a hull and there's a hydroplane, the two basic hydrodynamic designs”, he told me in April while we sat in his blue Chevy Suburban parked on the ocean side of Highway 101 at La Conchita.“A hull you would liken to a sailboat, which has a deep, rounded curved surface that extends down into the water.The pressure that the vessel has pressing against the water displaces water from the heavy rounded surface of the boat's hull as it passes through the water.It creates forward propulsion.
“Hydroplane, he continued, is a flat or concave surface which creates lift and brings the board immediately to the surface and planes on top of the water.The obvious differences are that one board quickly gets up to speed as it comes up on top of the water, but also quickly tops out, where you lose control once you get going too fast, so you have to put all kinds of fins on them to keep them in the water.Whereas a displacement hull reaches a terminal speed after a series of driving turns, and you build speed from one turn to the next.
“Another analogy is driving a stick shirt sports car, when you accelerate and power shift through the gears to gain speed.On a hull you're driving from one turn to the next, and the object is to connect yourself down across the wave into the pocket and bank off that angle and create additional speed.Unlike a hydroplane, you never reach a point where the board loses control.It's always attached to the water, and you maintain control at any speed.It's a more fluid, natural design that goes through the water more so in the way that a fish or a dolphin or a tuna would, as opposed to taking a flat stone and skipping it across the water, where its detached from the surface.”
“The pressure that the vessel has pressing against the water displaces water from the heavy rounded surface of the boat’s hull as it passes through the water. It creates forward propulsion.”
How does displacing water create forward propulsion? I need to know this secret, It seems to create drag on my paddle boards. -C
The words:
'it creates forward propulsion' seem a little ambiguous. Maybe what
is meant here is that the hull's rounded bottom displaces water smoothly
and
facilitates laminar flow, which helps create forward propulsion? A
hydroplane
surface will displace the water with turbulence, so it will build and
loose
speed in a less flowing manner. I like it when he goes on
to say: 'It's a more fluid, natural design that goes through the water
more so
in the way that a fish or a dolphin or a tuna would' as in my
experience a hull will make you feel
intimately connected to the wave and its unfolding forces. By the way
shouldn’t
his post be part of the Hulls Second Thread, where all things hullish
are kept?
I'm no expert and i'm sure there are many on here more qualified to answer but my understanding is that surfboards are generally either displacement hulls like Tom Wegener's boards which are deliberately slow and stable to facilitate noseriding. I would think this would be achieved through such design factors as weight and rounded resisting rails. I have a dvd somewhere with I think Joel Tudor riding a traditional log at Malibu and when he trims and walks to the nose the board is virtually all under water. I would think of that a displacement hull where the board's speed is being generated by the wave within. On the other hand there are hydroplaning hulls of which the Bob Simmons boards would be a good example. They would be very fast and yet stable if the waves are not too big and the fin set up is appropriate.I was previously riding a 10'^6" trad noserider weighing 31lbs and now recently a 6''4" mini simmons (light epoxy) and would consider the former a displacement hull and the latter a hydroplane. If its speed you are after I don't think displacment is first choice. But I await the repsected experts...
I'm no expert and i'm sure there are many on here more qualified to answer but my understanding is that surfboards are generally either displacement hulls like Tom Wegener's boards which are deliberately slow and stable to facilitate noseriding. I would think this would be achieved through such design factors as weight and rounded resisting rails. I have a dvd somewhere with I think Joel Tudor riding a traditional log at Malibu and when he trims and walks to the nose the board is virtually all under water. I would think of that a displacement hull where the board's speed is being generated by the wave within. On the other hand there are hydroplaning hulls of which the Bob Simmons boards would be a good example. They would be very fast and yet stable if the waves are not too big and the fin set up is appropriate.I was previously riding a 10'^6" trad noserider weighing 31lbs and now recently a 6''4" mini simmons (light epoxy) and would consider the former a displacement hull and the latter a hydroplane. If its speed you are after I don't think displacment is first choice. But I await the respected experts...
That reads like an excerpt from a magazine article; if so those may not be Mr. Andreini's exact words. Some ''paraphrasing'' may take place between the interview and publication. I wouldn't read too much into it.
I've been pretty lucky when I've been quoted in mags. Some quotes have come out untouched. But usually there's an ''adjustment'' or two.
jdo2 - I agree. I didn't get too worked up about that wording, although I saw it too, because often shapers / designers talk in shorthand, where a simple statement condenses a book full of background information, so you can't always take every statement at face value. His overall message was interesting I thought, in explaining the thinking behind the hull design.
I didn't post it in the hull thread, because the title of the thread indicated that it was for showing pictures of your hull surfboards. I don't have any hull surfboards, or any pictures to share. Just thought it was an interesting article.
Mike - I was typing as you were posting! That's pretty much the way I viewed it too, not worth getting too worked up too much over one sentence. I have had a few articles published that I wrote, and one in particular, when the publisher sent me the proof, I didn't even recognize it. Also, like I said in my previous post, sometimes people just make simple statements when there is a lot of background thinking that they're aware of and we're not. My wife does that all the time, I tell her that her brain is leap-frogging and slow down and explain herself. Anyway, agree with the man or don't, I still found his take on the hull concept enlightening for the uninitiated like myself.
actually simmon's boards aredisplacement hulls and can be ridden in surf way overhead as bob himself did many times. ( an old friend(bob was his hero being a goofy footer and all, has video of bob surfing the coast between rincon and points south. some pretty cool stuff for sure!)
Huck, hulls are often put to the
test
verbally in the Post your Hull pics thread too, so there are some
answers to these
recurring questions in there, but I would recommend you give a Vaquero a
try
and see if you don’t like that feeling…
Yes thanks Matt. I was thinking of the modern mini but have seen pics of Bob riding some big waves no problem. But I still don’t understand how his boards were displacement hulls. I think of them planing over the top of the water. Is displacment taking place initially at the nose through the bellied bottom and being directed/displaced towards the eliptical rails? I’ve built one simmons like board and want to build another better one so want to understand this concept. Thanks
Dan Forte and Michel Junod make modern pigs like the one you are describing. google it and you will see. I don't know how well a pig would noseride on the shoulder because of its narrow nose, but in the pocket noserides would work very well. Also check interviews with respected shapers on the subject by going to surfapig's blog. hope this helps you.
The hull guys like to go fast. The noserider guys like to go slow so they can spend more time on the nose. It seems to me that those design elements would be working against each other.
I agree with you about good noserides happening at slow speeds and the type of pig board that is being discussed would certainly not be a "noserider", but I do think that you could certainly get some tip time when speeding through fast sections. If i remember correctly, junod discusses the noseriding capabilities of his "pignar" model on surfapig's blog.
pig shapes, including the pignar, will nose ride well but they only tend to do it in the steep pocket of the wave, they won’t allow you to noseride out on the shoulder like more wide nosed paralel template boards. my experience of them is that they will trim fast in steep parts of the wave even on the nose.
Hulls themselves are as much about the feel you get surfing them as anything else. There is something wonderful about the deep rail engaged bottom turn spring from the fin and highline trim that is different from anything else
Please take my post with a grain of salt. I’ll be describing from my own experiences and views.
Hulls don’t work like conventional boards. They travel through the water, mostly during a bottom turn. The drop in is just to gain the speed for the foil to start working during the bottom turn. The round bottom and placement of the rocker apex work as a foil that creates inverted lift/drive. Drive is a confusing term to me as I associate it with a mechanical concept. Flow seems more appropriate. Trying to find the path of least resistance works for hulls. Try and make a good paper airplane with a proper foil, then try and get it to glide as far as possible by adjusting your throw or angle you throw it at. If you throw it with too much force while holding it at a high AOA, the foil will push air and not glide or flow. That’s how I feel a hull works in the water or that’s how I want to harness the momentum. Taking the proper line is a balance of time speed and direction and I think its very crucial to attaining the fifth gear speed. Conventional styles of surfing depend on the weighting and unweighting. Short moments allow the surfer to “jump” as a means of fwd movement. Hulls need to be pointed in a trajectory of least resistance to gain momentum. It’s my understanding that hulls fly through the water when properly foiled and piloted.
I’ve been studying this design for a while and I’m playing with the design myself. I took some video in hopes to analyze how the boards work in real world conditions. The first board is a Liddle Burrito . The 2nd and 3rd boards are two that I designed. After watching those boards, I can tell where I need to make adjustments in volume and widepoint placement for that rider. There are some moments when he gets the board to “flow”. If he would have changed his angle of projection, the board would have flown up into a better spot instead of into the lip (which he skillfully recovers from). What is apparent is the superior trim speed of all the boards and you can see in the clip that the Burrito actually pulls away and overtakes “planing” designs.
**Agreed… out of context or at least a misstatement by Marc. **
**Regardless if a planing or displaement hull, like fish, surfboards depend (for the most part) on fins for directional stabilty. **
**But even more so, they rely on LEVERAGE from a relationship of rail to fin, bottom configs to fin(s) for (forward) propulsion. Even bottom relationships to finless boards…hence the Auga board.
**
A finless displacement hull will not inherently being propelled forward merely because it is a displacement hull.
A battleship is a prime example of displacement, but then again look at the source of propulsion.
At the end of the day, I think it is both wonderous and beautiful that we can play with all the compound curves to concoct a ride that some will rave about and others will meet with disdain.
**It’s the differences that make this world interesting. **
The term LEVERAGE says it all with hulls. It is all in how you want to ride. Pivot from the tail, or turn from the center. Front foot vs. back foot. You have to ride the hull with that distinction. You can't get on it and ride like a longbord or hpsb. Apples and Oranges.
-C