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Displacement hulls

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Created by webster > 9 months ago, 11 Sep 2012
webster
WA, 25 posts
11 Sep 2012 9:59PM
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Anyone renowned for shaping thiese or someone selling them in Perth

Ted the Kiwi
NSW, 14256 posts
12 Sep 2012 8:13AM
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MUrray Bourton makes boards with cathedral hulls.

www.bourtonshapes.com

swalkington
WA, 401 posts
12 Sep 2012 12:27PM
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Try Hayden shapes as well. Think his psychedelic germ model has a hull. Can get em from star in perth.

Torch
WA, 521 posts
12 Sep 2012 1:55PM
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I learnt something today

www.surfscience.com/topics/surfboard-anatomy/bottom-contour/displacement-hulls

jbshack
WA, 6913 posts
12 Sep 2012 4:00PM
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Me too, and considering Ive got a brand new Bourton yet to be ridden i hope i like it now. I have always liked riding of my back foot

doggie
WA, 15849 posts
12 Sep 2012 4:03PM
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jbshack said...



Me too, and considering Ive got a brand new Bourton yet to be ridden i hope i like it now. I have always liked riding of my back foot


I think displacment is different to your board JB.

PaddlePig
WA, 421 posts
12 Sep 2012 8:31PM
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I don't want to be a know it all tosser, but I think the term 'displacement hull' is a **** name. It seems in surfboards they call a vee bottom displacement hull. But plenty of ski boats and run abouts etc are vee bottom and they are planing hull. I think any short surfboard in the world that you can stand on while it is not moving is actually a planing hull. I mean that, the forward movement creates lift.

PaddlePig
WA, 421 posts
12 Sep 2012 8:36PM
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Actually, maybe the term 'displacement hull' isn't too inaccurate. I just read that website and it says if the surfboard goes too fast it would submarine. That's right I guess. When I think displacement hull I think of tankers at freo. And they have a speed limit they physically can not go faster than. Maybe I'm wrong.

doggie
WA, 15849 posts
12 Sep 2012 8:41PM
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PaddlePig said...

Actually, maybe the term 'displacement hull' isn't too inaccurate. I just read that website and it says if the surfboard goes too fast it would submarine. That's right I guess. When I think displacement hull I think of tankers at freo. And they have a speed limit they physically can not go faster than. Maybe I'm wrong.


You are right about the ship type hulls, they use the type of hull in racing SUPs.

Funny pic but these are displacement hulls.

PaddlePig
WA, 421 posts
12 Sep 2012 9:11PM
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Yeah that's what I meant leg rooter. Those racing SUP board would be displacement hulls. But then again, I don't want to sound like a know it all. My opinion is based on nothing. No uni degree. No papers or other things. Just a bloke.

Ted the Kiwi
NSW, 14256 posts
12 Sep 2012 11:16PM
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doggie said...

jbshack said...



Me too, and considering Ive got a brand new Bourton yet to be ridden i hope i like it now. I have always liked riding of my back foot


I think displacment is different to your board JB.


+1

Yep very diff. I think in that article Paddlepig that they are referring to boards with noses more like the downwinder and flat water boards in the 666 room. Completely diff to the bourton hulls which are designed for paddling into waves by creating lift.

webster
WA, 25 posts
12 Sep 2012 9:50PM
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yep the type of board im looking for are the ones vouch surfboards shapes (over east)or the v bowl ryan lovelace shape



DrD
64 posts
13 Sep 2012 9:59PM
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doggie said...

PaddlePig said...

Actually, maybe the term 'displacement hull' isn't too inaccurate. I just read that website and it says if the surfboard goes too fast it would submarine. That's right I guess. When I think displacement hull I think of tankers at freo. And they have a speed limit they physically can not go faster than. Maybe I'm wrong.


You are right about the ship type hulls, they use the type of hull in racing SUPs.

Funny pic but these are displacement hulls.






I think the label on these boards is a bit mis-leading. In the shipping world a displacement boat sits in the water, the amount of water it displaces creates pressure, as pressure is equal in all directions, the same pressure pushes back, allowing it to float. Boats of this style are limited in their speed by their length.
Boats that float on the water are known as semi displacement, or planning hull. These boats can reach high speeds, but are less sea worthy. Commonly seen on fast power yachts and fast ferries.
Two very different designs, allowing two very different style of boat. To call a surfboard displacement is incorrect.
I don't even think those racing SUP's would be classed as displacement.

Now I have bored you with boat design, I feel my work here is done

Although I would love to see someone paddle out on something like your picture, just for comedy value

doggie
WA, 15849 posts
13 Sep 2012 10:13PM
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DrD said...

doggie said...

PaddlePig said...

Actually, maybe the term 'displacement hull' isn't too inaccurate. I just read that website and it says if the surfboard goes too fast it would submarine. That's right I guess. When I think displacement hull I think of tankers at freo. And they have a speed limit they physically can not go faster than. Maybe I'm wrong.


You are right about the ship type hulls, they use the type of hull in racing SUPs.

Funny pic but these are displacement hulls.






I think the label on these boards is a bit mis-leading. In the shipping world a displacement boat sits in the water, the amount of water it displaces creates pressure, as pressure is equal in all directions, the same pressure pushes back, allowing it to float. Boats of this style are limited in their speed by their length.
Boats that float on the water are known as semi displacement, or planning hull. These boats can reach high speeds, but are less sea worthy. Commonly seen on fast power yachts and fast ferries.
Two very different designs, allowing two very different style of boat. To call a surfboard displacement is incorrect.
I don't even think those racing SUP's would be classed as displacement.

Now I have bored you with boat design, I feel my work here is done

Although I would love to see someone paddle out on something like your picture, just for comedy value



Just look in the SUP forum and you see it alot !!

PaddlePig
WA, 421 posts
14 Sep 2012 1:05PM
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Yeah that's what I meant too. I thought displacement hulls had their length in feet, then square rooted, then times by some number like 1.6 or something, and that's their top speed in knots. That's why it sounded to me that a surfboard couldn't be one. Good to hear a bloke who knows what he's talking about chime in, thought I was going out on a limb claiming it didn't sound right.

Who cares though, the surfing looks great.

arkgee
NSW, 639 posts
14 Sep 2012 3:56PM
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I always thought displacement hulls in surfboards meant bowls not concaves...where a bowl in the nose will form a high rail...thus the high/low railer...producing a rail that is soft almost spongy to ride...where the concave will plane early...and produce a more defined edge to turn on and a board that will feel more precise through its turn...they both plane though so I guess the name does not really suit....I based my free range egg design on this theory and they are a very fast little board....I have run the concave into the bowl which has produced a very interesting board to ride...its great taking old stuff and blending it with modern ideas....I think we will see a lot more of this as surf design starts to go a little like fashion....the basic short board has gone about as far as it can go...(and to be honest bores the crap out of me.)


..so designs will come into, and go out of fashion

SP
10979 posts
17 Sep 2012 5:06PM
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This one is from rake, on it's way to three stories surf shop in WA, if that's what your after might be worth a look, nice looking board..

Nice boards RG..

swalkington
WA, 401 posts
17 Sep 2012 5:19PM
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^^^^
Can anyone explain why quads seem to go so much faster than a standard thruster. With a extra fin common sense would have me thinking the extra fin would create more drag and slow the board down. But I know that's not the case as I have a quad in my quiver. In my opinion the quad is the board of choice for super hollow fast beach breaks.

blueprint
WA, 321 posts
18 Sep 2012 8:53AM
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swalkington said...

^^^^
Can anyone explain why quads seem to go so much faster than a standard thruster. With a extra fin common sense would have me thinking the extra fin would create more drag and slow the board down. But I know that's not the case as I have a quad in my quiver. In my opinion the quad is the board of choice for super hollow fast beach breaks.


I'm no expert but I got to thinking about this the other day and two things come to my mind

1. The trailing fin basically sits in an area where water is still tubulent/slightly turbulent from the leading fin (within what engineers would call a boundary layer)meaning that though there is more SA from a fin perspective you won't see the substantial increase in drag you'd expect.

2. It's not all about drag, the quad's are just more efficient at converting drive into speed, try swapping fins if you have a 4/3 setup. Paddle out catch a wave and just trim (don't pump the thing, which you'll find hard) you probably won't find much difference, go to a single though and do the same and you'll see a massive difference (it'll be heaps faster) point is the quad's holding better and converting the pumping/driving motion into speed better

2c but it's the best I could come up with

doggie
WA, 15849 posts
18 Sep 2012 9:29AM
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^ Spot on blueprint



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"Displacement hulls" started by webster