step ups and concaves

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step ups and concaves

Postby Tomdiddlybomb » Sat Oct 14, 2017 1:23 pm

fairly apt, what with a 'hurricane' arriving in a few days time :-D I was thinking about step ups and why they have concave bottoms...
a concave creates lift and high pressure under the board, useful for small waves but just about the opposite of what you need once it gets big
my 2 favourite boards both have flat and V bottoms, and they seem to feel much more composed at high speeds than a normal shortboard with concaves
so why do the majority of step ups have concaves?

I've been planning on building a couple of boards over the winter, and one of the designs I've drawn up is a shortish thick step up, but I don't know if I should go with a concave or convex bottom. It's going to be a quad so it will have a small amount of V in the tail either way, and convention says go with a concave, but my experiences say go with a V bottom...

anybody got any experiences with a few different boards in heavy waves and know what works best for certain conditions?
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Re: step ups and concaves

Postby Tomdiddlybomb » Sun Oct 22, 2017 7:38 pm

never mind then... :lol:

the forum will live, it just needs some cpr, or tlc, or some other three word abbreviation...
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Re: step ups and concaves

Postby JayP » Mon Oct 23, 2017 8:22 am

L.S.D.
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Re: step ups and concaves

Postby Philchapman » Mon Oct 23, 2017 10:17 am

Lift Speed Drive?
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Re: step ups and concaves

Postby Leven » Mon Oct 23, 2017 4:32 pm

Tomdiddlybomb wrote:never mind then... :lol:

the forum will live, it just needs some cpr, or tlc, or some other three word abbreviation...



It's probably just that no one knows the answer!!
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Re: step ups and concaves

Postby Tomdiddlybomb » Mon Oct 23, 2017 6:46 pm

forums are just too old-school, I'd be willing to bet I'm the youngest semi-regular poster on here.

so I take it nobody here has played with convex vs concave in proper waves...? :roll:

slightly different take, does a convex bottom help catching waves? extreme example would be a hull, sitting deeper in the water so tapping more energy from the wave that bit earlier. I know a few guys on here like hulls, might get some conversation going :lol:
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Re: step ups and concaves

Postby Black » Mon Oct 23, 2017 8:36 pm

My bottom is convex but I don't think it helps me catch any more waves.... :arrow:
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Re: step ups and concaves

Postby Philchapman » Thu Oct 26, 2017 6:13 pm

Okay, I'm bored, I'll bite. Answering your questions in order...

1). Because concaves help you generate speed for racing gnarly tube sections dude.
2). Define 'heavy'. If heavy is whatever you personally find challenging, then Yes (which isn't saying much).

That answer everything?... No, didn't think so.

Why does it have to be one or the other? I think you'll find that a lot of shapers will use concaves transitioning into V off the tail. That would be my preference also (in the form of a Bonzer). Maybe find some inspiration here?...

http://www.boardcave.com/the-surfers-corner/step-ups/

Post some photos when you're done? :D
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Re: step ups and concaves

Postby Tomdiddlybomb » Fri Oct 27, 2017 1:57 pm

Concaves don't really generate speed though, they generate lift. speed comes from rail line and rocker much more than concave. and yes I know, slightly different ball game when it's small, because lift brings the board out of the water which reduces drag...

I think sometimes concaves can be described to sound like there's much more 'science' behind the way the board works, but in my experience simple is usually better. (bonzer excluded from all this, of course) I think I need to try a couple of boards and maybe make 2 different identical boards with concave and convex bottoms and see what I prefer.

bold of you :lol: you have no idea what I find personally challenging :wink: but this isn't going to be a gun, just something for those days when it pushes a few feet overhead and hopefully gets hollow. Honestly not going to see much use in the uk, I'm planning a year or 2 in NZ after the winter finishes here.

and no you're right, doesn't have to be one or the other. I class a concave with small amounts of V for the last 6 inches of the tail as riding similar enough to a full concave to be close enough though. just seems that's the sort of bottom you find on a multi-finned board, and convex on 'retro' single fins and the like. I have a feeling that a convex bottom quad could have all the speed of, and more composure/less chatter than a standard step up. helping your fairly average surfer (yours truly) get some TOOOBS. We will see

I wasn't necessarily after hard and fast answers, rather a bit of lighthearted discussion and anecdotal evidence.
but once I figure out where to build a couple of boards I'll start a build thread. first up is a keel fish for good waves though :-D
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Re: step ups and concaves

Postby Leven » Fri Oct 27, 2017 3:13 pm

Concaves = hydrodynamics.

If you're surfIng overhead hollow waves, do you want speed or control? Deeper concaves will draw more water through them giving speed. Less will slow the board down. I think!?

Personally, with my step ups I go for a straight forward single, that's a bit deeper than normal. The wave will give you speed, so I prefer control and stability....

For fun, put your boards upside down in the garden, and run a hose pipe on them nose to tail, you'll see how the water flows! Fascinates me!
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Re: step ups and concaves

Postby Philchapman » Fri Oct 27, 2017 3:23 pm

I don't think any bottom shape generates speed in and of itself, but my own personal take on concaves is that they give you something to push against, given that you are usually pushing at an angle across the wave face, and that pushing against something generates the speed. That's if it's a good shape and all the other variables are in sych., rail line/rocker and such. I think Bonzer riders would dispute your statement that concaves don't generate speed, given the above proviso. Yes, you can push against fins in any board, but comparing how hard you can push a thruster in turns vs a good Bonzer, I found that I personally couldn't get a Bonzer to slide out. All effort/ momentum goes into forward motion.
Same (maybe to a lesser degree) with any board with decent concaves.

No, I have no idea what you find personally challenging. I was kinda saying It doesn't take much for me to find conditions challenging!

A year or two in NZ? Oh, I can but dream. Cracking place. A perfect testing ground.
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Re: step ups and concaves

Postby Black » Fri Oct 27, 2017 3:33 pm

Ah, if its anecdotal evidence you want then I'll pipe in as I know nothing about all that other shit.
The last two boards I purchased were supposed to be mush busters but I've found they are also great in the bigger waves I've surfed. I've used them both exclusively in the last 7 days or so in the big swells we've had down here and not for a second did I think I needed anything else. I have two other boards I might have used previously but it seems they are redundant now! FYI they are both single to double. I suspect the rocker is far more important but they are both different???
Not sure how relevant/useful any of that is as there's big and there's BIG! What's big?

PS there was an interesting interview with Campbell about the biscuit bonzer on t'internet recently, he talked bottom contours.
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Re: step ups and concaves

Postby Black » Fri Oct 27, 2017 3:41 pm

Here is the video.....
https://youtu.be/H8JqDlcZU2w
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Re: step ups and concaves

Postby Philchapman » Sat Oct 28, 2017 10:20 am

Thanks Black. Malcolm = humble as ever. Want to see more of Bobby Martinez on that board in better waves.
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Re: step ups and concaves

Postby Black » Sat Oct 28, 2017 11:05 am

Philchapman wrote:Thanks Black. Malcolm = humble as ever. Want to see more of Bobby Martinez on that board in better waves.
Very humble and his explanation of that board is more sensible to me than any other shaper I can think of - no bullshit.
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Re: step ups and concaves

Postby thechimp » Mon Oct 30, 2017 5:41 am

The last step up i had was a Dave Stubbs 7'10 slight vee throughout, rolled deck, pretty flat rocker, that was quite a few years ago, these days my step down is an 8' Nugget.
Have a look at webby's comments re 'Step ups' and also on guns, he is now making boards for the worlds best big wave riders not just aussies, i've noticed the big difference in volume up front and in the rail from the thin semi guns of the past.

http://www.webstersurfboards.com.au/step-up-surfboards/

On another note as you mentioned NZ, you may find this thread of interest

http://www.swellnet.com/forums/wax/371835
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Re: step ups and concaves

Postby Archy_is_God » Fri Jan 05, 2018 11:02 am

Just being pedantic but 'step up' boards are not strictly big wave boards and around 15yrs ago the term did not really exist - you had shortboards and semi guns. It's another marketing term to sub categorise the shortboard market really. Therefore they are best viewed as a tuned up shortie rather than a detuned gun and share similar attributes.

However, the statement above will mean completely different things from shaper to shaper, depending on their school of thought...

Maurice Cole will tell you how a deep single will go insane in waves 2ft to 40ft if built right, Greg Griffin will explain how a flat bottom will be all you will need 99%of the time, Jeff Clark may suggest that vee throughout is sensible for waves of consequence and they would all be right.

That wasn't very helpful was it? :lol:

For the most part, a line appears to be crossed whereby concave is used less and vee/rolled vee/flat bottoms are utilised.

Rails and rocker are crucial in all cases and to a lesser degree, planshape.
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Re: step ups and concaves

Postby Archy_is_God » Fri Jan 05, 2018 11:17 am

Just to add, there is a 'fastest bottom' for water to travel across and off (in scientific terms at least) and it is a completely flat surface with knife like edges that release it. Obviously this does not consider any other variable and assumes the water runs straight across the bottom..

Such edges are not easy to control on a surfboard but can be used to good effect if done right. Greenoughs edge boards are an interesting concept that attempts to utilise the release when it's useful and prevent release when it's not wanted.
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Re: step ups and concaves

Postby Tomdiddlybomb » Fri Jan 05, 2018 2:07 pm

nah you're right, I'm not on about a full-on gun... I'm on about a board for when you want to get in reasonably early, and hopefully look for a tube you can stand tall in, and probably cut through a load of wind chop on the face. The sort of waves where a normal shortboard feels too light and too twitchy
guess that's my own line as you say, where a concave outlives its usefulness

I suppose I am looking at this from the other end; a detuned semi gun rather than a tuned up shortboard. Think that might really make it an easy board to surf in not so easy waves

just gotta build the thing and see I guess!
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Re: step ups and concaves

Postby Leven » Fri Jan 05, 2018 4:42 pm

Just picked up a 7'10 call it what you want (7'10 x 20 3/4 x 2 3/4). Will use it in waves as big as I'll surf.

Personally, I wouldn't stray too far from what you normally surf, particularly towards a gun. Guns (even watered down versions of them) are in my experience really difficult to surf. They only come alive in waves of consequence, are way thicker than an average shortboard and are actually hard to handle. VERY different experience.

For my money you'd be better off going for something closer to the type of template you're most comfortable with in good waves, and just packing some more volume into it. Extra few inches in length, quarter to half and inch thicker (keep the rails the same if you like - That's what I've done), same in width max. If they're good, hollow waves, you're unlikely to need to generate speed, more control, and you'll feel much better surfing something closer to what you're comfortable with.

Also, if you're wanting to reduce the twitch and get in early, think weight. I've just had this glassed in 6+6 on the deck (with a small patch) and 4 on the bottom. Gives it some weight to cut through chop, and helps to get in early.
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Re: step ups and concaves

Postby Tomdiddlybomb » Fri Jan 05, 2018 6:07 pm

I normally surf a 5'4 keel fish... in waves up to nearly double overhead as long as it's not way too steep. I'm planning a step up version of that too, but that's a whole different kettle of fish, if you'll pardon the pun...

but when it gets big my go-to options are a 6'0 warner quad I picked up in WA that works well when it's steep, but is super light eps/epoxy so is no good in chop or strong offshores, and a 6'4 singlefin that gets in well, goes fast as hell in a straight line, but lacks a few of the obvious things you get with more fins
the singlefin is the one I feel most comfortable on when lots of water starts moving, it's a nice teardrop template, panel vee all the way through, beautiful thin rails, but not quite enough rocker for really hollow waves.

yeah the waves that require a nearly 8 foot board scare the tits off me... I'm talking about something 6'0-6'6. I know that's short for bigger waves, but I'm a pretty small guy so I need to scale down. Or have I got too much expectation for such a short board? I don't know? I've always gone on the shorter side because I've borrowed longer style step ups and shortboards and HATED them

so with all these opinions thrown in, I'm here; 6'4ish, wide point forward, panel vee, thickness under the chest, quad, and a little more nose and tail rocker than my singlefin... and the heavy glassing is a given, I'm really not a fan of light boards

or knock it all on the head and build a big wave fish? :lol:
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Re: step ups and concaves

Postby Archy_is_God » Fri Jan 05, 2018 9:18 pm

Or go the Widow route.. Single on viagra
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Re: step ups and concaves

Postby Archy_is_God » Fri Jan 05, 2018 9:23 pm

Or have a look at Spider Murphy's Glockenspiel model - a stumpy semi gun. That's an interesting design.
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Re: step ups and concaves

Postby Tomdiddlybomb » Fri Jan 05, 2018 11:29 pm

Archy_is_God wrote:Or go the Widow route.. Single on viagra

funnily enough I typed that out but deleted it. I'm on such a twin and quad hype at the moment
probably going to have quad boxes and a single box in the middle anyway
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Re: step ups and concaves

Postby Tomdiddlybomb » Fri Jan 05, 2018 11:49 pm

Archy_is_God wrote:Or have a look at Spider Murphy's Glockenspiel model - a stumpy semi gun. That's an interesting design.

all I could find was a paragraph saying it's got some funky channels and paddles a foot shorter
sounds interesting but sadly there's nothing on the internet to be found
Oh and I guessed it was glock not glockenspiel :lol:
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Re: step ups and concaves

Postby Black » Sat Jan 06, 2018 10:43 am

Glockenspiel - now that rings a bell!







Ok I'm gone :arrow:
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Re: step ups and concaves

Postby Archy_is_God » Sun Jan 07, 2018 10:00 am

Bloody autocorrect....

Glock, not Glockenspiel..... :roll:
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Re: step ups and concaves

Postby Archy_is_God » Sun Jan 07, 2018 10:35 am

Template is a bullet nosed roundtail with fairly parallel rails. They are thick throughout with belly channels (Spider calls them 'Hydro' channels) Quad or thruster I think
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Re: step ups and concaves

Postby Tomdiddlybomb » Mon Jan 08, 2018 11:12 pm

Leven wrote:Personally, I wouldn't stray too far from what you normally surf, particularly towards a gun. Guns (even watered down versions of them) are in my experience really difficult to surf. They only come alive in waves of consequence, are way thicker than an average shortboard and are actually hard to handle.

coming back to this, what (in your experience and opinion of course) makes guns so difficult to surf? having never surfed anything that required a full blown gun I have no idea what you're on about. I've surfed a lot of deeply deeply weird boards and usually get on better with them than standard shorties, so that seems a bit alien to me
is it more the wave that makes it hard, or truly the board itself?
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Re: step ups and concaves

Postby Leven » Tue Jan 09, 2018 1:24 pm

So, in my experience, guns are just totally different to anything else I've ever surfed. The length (I've surfed 8'0 to 9'6) is ok, but combined with narrowness, a lot of thickness, and the overall template makes them actually quite hard to paddle/manoeuvre. In anything other than heavy, powerful waves they feel sluggish, slow and cumbersome. Basically, they're extreme for extreme waves.


I've settled on step up boards (a 7'6 and a 7'10) where actually there's very little extreme about them. Simple template (rounded pin, wide point about midway, thickness through the middle all through the nose, with foiled rails, quad+single box, deepish single concave all the way through), solid glassing (6+6+patch+4 on the bottom), two leash plugs. They're not incredibly fast, they don't turn on a dime, and they're not ultra light.


BUT, they're solid, they're stable, they get you in early, they allow you to lean forward and drive to the bottom, they hold a line, and they don't skit around all over the place. For me, that's what I want in solid waves. I don't want speed, the wave has that, I want control and stability. I would say the rails are massively important. I've had other step ups where the rails weren't as foiled, and they were horrible. Thickness through the middle is great, and combined with length gets you in early, thinner rails makes it surf-able. For instance, my 7'10 x 2 3/4 has the rail profile of a 2 5/8 board, so quite a bit thinner than you'd expect on a board that thick.


If you like your 6'4 Single, why not base it on that with some refinements? I'd definitely add a few inches (length gets you in earlier), and keep the thickness through the middle. Quad and a single box works on mine (although rarely use the single box). Bear in mind the last thing you want is to pearl, so consider keeping the thickness through the middle further toward the nose to.
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