Board design by Ola H.

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Ola H.
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Board design by Ola H.

Post by Ola H. » Tue Jan 01, 2019 1:58 pm

In the old Boards forum I used to have a long thread running where I posted about new boards in the works or already in the water. It originated in a post about the first Simmer Frugal prototype and therefor went byt the title "The Frugal Fish is in". I enjoyed the discussions and I like the idea of being rather open with my work, so now I'm opening a similar thread here.

The first posts will be a showing off two personal boards I'm working on. Most but not all my innovation comes from personal boards. The advantage is that I can experiment more freely, but the disadvantage is that I have a relatively particular taste in boards and that some of the boards I like the most and that are over many years developed to work with my sailing style are a bit extreme for most. Nevertheless, a successful production board like the Cortex as well as the original Simmer Quantum was also developed for myself at first, and so was the now discontinued Frugal.

Anyway, two favourite boards of mine lately have been the Torrent (209x56.5@73 liters) and the Limelight (216*55.5@ 73 liters). In subsequent posts I will describe each one of them and some of the design history that led up to them. Later I’ll follow up with intentions and inspirations for their respective follow ups. 

To start off: a bunch of boards I made over the years in the 55.5-56.5 width span, 73-83 liters, lengths 209-236 cm.

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Last edited by Ola H. on Wed May 15, 2019 10:05 am, edited 1 time in total.

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Re: Board design by Ola H.

Post by northy » Tue Jan 01, 2019 10:10 pm

looking forward to hear more Ola!

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Re: Board design by Ola H.

Post by Ola H. » Wed Jan 02, 2019 10:07 am

So, let’s talk about the Torrent 73 then. Seen from one angle, this board has a very long heritage where the key has been functionality, but seen from another angle it was born on lightning strike of inspiration and lust of experimentation

The first angle is incarnated in the rocker and bottom profile. The first Torrent has the same rocker as the Cortex production board. Low center rocker, relatively low front rocker and a pretty low tail rocker too. All coupled to double concave v. The rocker along the rails increase quite radically towards the tail, by means of an accelerating v. Except for this latter detail, the bottom was carried over from Kai Katchadourians Jaws board, which in turn comes from a variant of the bottom that was developed for what became Simmer Style’s first Freewave board in 2012. At the time, it was the first convertible board on the market and the rocker was designed from the ground up to work both as a single fin fast tail and as a turny tri fin with rather big front fins. Since then, this very rocker has turned out to be immensely versatile and it has been used on various customs, goes well all sorts of fin setups and is also the basis of the recently released Simmer Fly v4 ground swell wave board.

The other angle of the Torrent comes from surfing inspiration which also explains the name. I saw a sick video clip of surfer Torren Martyn riding macking Nias on his baby blue 5’4” twin

I was struck by the flow of that board. I decided it was time to design a windsurf board that could work as a proper twin, that is with two large fins placed far forward close to the rail (not the rearward mounted and pretty centered fins that usually go by the twin fin designation in the windsurfing world). I also had in mind my main break in Portugal, which is a wave that gets rather steep and with some wall, but still it is hard to generate speed when dropping in on this wave. So I was thinking a very fast board would suit that wave. I had already sailed a bit on the Cortex, which has a rather low curvature outline. Less outline curve in the active part of the bord equals less drag, something which is key design feature on a fish style board. The Cortex has a square nose and an extended outline in the nose, so for the Torrent, I moved the widepoint forward, straightened the curve even further in the back and pulled in the nose to for a rather classic fish outline. Incidentally, just like Torren Martyn’s fish, the Cortex already had a subtle winger and a pulled in but straight section behind the winger. This was something I implemented to give the board both a bit more snap (the pull-in) and more stable grip in the top turn (the straightness). So I kept this on the Torrent, but changed the diamond tail on the Cortex to something more similar to the moon tail on Martyns surfboard.

Here is the original Torrent 73 on top of the Cortex 78

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The name Torrent came about as a bit of a twist on Torren Martyns first name. Torrent also meaning fast flowing stream, which fits well with what the board was about. What about the fins then. Well, it took some time until I got ahold of some proper twin fins so I rode it mostly as a standard thruster, with fcs surf fins in the front (asymmetrical about 10cms) and a 15-16cm back fin which worked great. After some time I got ahold of some MR twins.

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In smaller waves, the feeling was pretty interesting in particular when the action was a bit slow. Super loose, but you have a lot of top turn bite so you can hook the board under the lip in a very nice way. But the board feels a bit sketchy too, so ofter a while I added a little trailer

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The jury is still out on the twin and twin+trailer setup because it get a little tracky at times when setting up the bottom turn, but I will spend some more time on it and see.

The board is still awesome in smaller waves and is super effective despite being relatively small. Here are some sailing pics from a small day.
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(photos: Brädsport)
Last edited by Ola H. on Wed May 15, 2019 10:14 am, edited 2 times in total.

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Re: Board design by Ola H.

Post by rod » Wed Jan 02, 2019 2:49 pm

Thanks Ola!
Look forward to the next instalments. I now have one of your boards (Quantum 90 G4, I know boring! but I love it) and I also tried the Cortex 99 which I would love to try again. I found the Quantum much better for high winds than the G3 Flywave. (as a heavy person getting boards that have float but are also controllable in a lot of wind and feel small is key).

(I also still have my now old Witchcraft 90 which has also served me so well and I am happy to have boards from the two board designers that have contributed so much to the boards forum. Long may it continue).

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Re: Board design by Ola H.

Post by Gorgesailor » Fri Jan 11, 2019 5:25 pm

Very nice Ola! ... Can you post some rockerlines, thickness profiles & rail shape as well? Interested to see how these all mesh together on such a board - especially compared to more traditional shapes...

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Re: Board design by Ola H.

Post by Ola H. » Sun Jan 13, 2019 10:47 am

Gorgesailor wrote:
Fri Jan 11, 2019 5:25 pm
Very nice Ola! ... Can you post some rockerlines, thickness profiles & rail shape as well? Interested to see how these all mesh together on such a board - especially compared to more traditional shapes...
I will come back to some discussions on rockers and the notion of curvature later. Some other stuff first...

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Re: Board design by Ola H.

Post by Ola H. » Sun Jan 13, 2019 10:56 am

So the Torrent 73 is an awesome board and it has been my go to board since last summer and in particular it has been a gem for light winds and slower waves despite being kind of small (I’m 70 kg myself, so it is not particularly floaty). It’s very similar to the Cortex, but just a few notches snappier and it fits tighter sections better due to less nose and it has narrower and thinner tail too. The outline and rocker makes it very easy to generate speed on, when the wave is not very big or generally when nor wind or waves give you speed for free in the drop in. But despite the effectiveness of this board, it is a bit on the small side. Moreover, the very straight outline between your feet means that the sailor has to drive it very actively when turning tight. Such and outline is fast and stable, but not in itself very loose. It is the short tail that allows this board to still turn tight, but as said, the sailor need to deliver quite a bit of input. 

So I was think ing about and update and/or a bigger companion around 80 liters and the result so far is a plan for a Torrent v2 79. As before, I used inspiration from surfboards and in this case Rob Machados new Seaside which is a specifically developed quad. Just like Machado did when he developed the twin fin GoFish to the Seaside, I have added a little bit more outline curvature between your feet. This pulls in the tail a bit, so I have removed the winger and now finish it off in a classic fish tail.

Here is it by itself and on top of the original Torrent 73.

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I have upped the width 1.5cms to 58 but the tail still ends up in similar width as the Torrent 73. I very seldom ride boards as wide as this, but over the years I have enjoyed some extra width at times

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Here is me riding the Freegal 80, which is 58.2 cm wide a few years ago. As seen, it comes around nicely in a full railed powerful top turn on a small wave. This is powered up 4.0, and I haver felt that this board felt too wide in the conditions I rode it in. And in any case I plan to have a narrower and more rockered board in my quiver too (and have a whole bunch of such boards in my garage since they are not the easiest to sell).

So how close is the planned Torrent v2 79 to the Freegal 80? Here are the outlines. As always I line my boards up by the back strap when I compare them.
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What do we see? The Torrent obviously has a shorter and more pointy nose which is created by a bit more outline curve from the mast foot an forwards, but a bit less in the very nose. The widepoint on the Torrent is 5 cms forward. But most importantly, the Torrent has less curve in the back. One way to see this is to note that the outlines intersect just in front of the mast box and at the front screw of the back strap and between these point the blue Torrent takes a straighter line. But a trained eye can also directly see that the green Freegal is curvier in the back half. Or you can mathematically or with a CAD software analyse curvatures. I will come back to some curvature theory in the future.

In the very tail the Torrent is much straighter than the Freegal though. In general outline curvature creates looseness and outline straightness creates stability on rail. If these is a lot of curve in the outline, the ”balance point” of the board relative the water when the board is on rail will depend a lot onhow the rider push the board. So the rider has a lot of influence over what part of the board that is in the water which makes it easier to ”push around” the board which is one important aspect of looseness. But with a straighter outline the board will stay more put on the rail even if the rider moves around a bit and turning the board requires more sailor input (all assuming the same rocker). But a curvier outline also drags more when the board is on rail. 




Another important difference to the Freegal is the rocker. The rockers are similar in overal curve, but very different in the flow, but I will come back to this point at a later post. 

So the design of the Torrent v2 79 is pretty much set and I will push the buttom and have it CNC:ed soon. I just broke a rib skiing so I’m off the water for a while and I’m not in a big hurry…



A last detail to comment is the fin setup. I ended up riding the Torrent v1 mostly as a standard thruster and sometimes as a twin with a small trailer. I’m keen to work more on getting the setup with larger fronts to work but (again a bit inspired by the Machados Seaside) I intend to experiment a bit more with a quad setup with larger fronts and the rear quad boxes are set with ”trailer quads” in mind. A little subtle thing I did to perhaps improve the stability when running the rear quads so far apart was to let the double concave in the v accellerate quite a bit extra towards the back, alsmost creating a bit of a spine along the center. (I might post a pic later).

I was pretty fond of the original Starboard quad with large fronts, but they had some drawbacks. But also the Torrent v2 will for sure run well as a standard thruster too, so I have this to fall back on on the days when I can’t get the more experimental setups to work. 




Check this video of the Machado Seaside to see where the surfing part of my inspiration for the Torrent v2 comes from.
Last edited by Ola H. on Wed May 15, 2019 11:24 am, edited 3 times in total.

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Re: Board design by Ola H.

Post by Ruaraidh_K257 » Sun Jan 13, 2019 6:00 pm

Really interesting write up as usual Ola. I look forward to trying out the Torrent 72 and 79 in the future. It looks like my kind of board. As for the bigger front fins, is that not likely to make the board a bit of a pig to turn?

Hope the rib gets better quickly; it’s not nice being off the water!

Heading out to Medano tomorrow, will post results of a FlyWave test ASAP 😉
16, Scottish wavesailor, sponsored by - Neil Pryde, JP Australia, K4Fins, Wild Diamond Tiree

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Re: Board design by Ola H.

Post by Ola H. » Mon Jan 14, 2019 4:58 pm

Ruaraidh_K257 wrote:
Sun Jan 13, 2019 6:00 pm
As for the bigger front fins, is that not likely to make the board a bit of a pig to turn?
Not really. What is hard is balancing fin power and engagement. If you, for example, run a board with just front fins (say a regular set of surf fins, which are typically way more powerful and have larger area than most windsurfing front fins). Then you will overall be a bit underfinned, but turning will be anything but pig-like. In fact, the board will be ultra loose and require a lot of sailor precision because it is so loose (as opposed to a fin setup that requires attention because it is to hooky or powerful). And yet you could hook some pretty good top turns on such a setup. Having your acting fins so far forward and close to the rail gives you as a sailor huge influence over how the fin engages and interact with the rest of the board. The problem is that is is too hard to control, so you need a bit of rear fin. And then you introduce a lot of competing forces and front and rear fins might engage a bit differently and as the rear fin becomes so big that it starts to override the front fin in power at times, it starts go get very important to get the fins to interact nicely.

In windsurfing we are used dominating rear fins (twin, single, thruster or quad) partly because of tradition and partly because of trim in a straightline. And with that as a starting point, front fins will remain rather small because very few people puts in the time to work out the tuning issues.

I used to sail a lot with bigger fronts, even before I went to riding only asymmetrical fronts. Typically 13 fronts and 10 rears. Gradually I then move towards surf style front fins at a size just under typical surf fins. Similar to K4 Ezzy 10cms. Then some low power 12-5-13cm rears or a 15-16 center fin. But as mentioned, I miss some things about even bigger fronts and a more front fin dominated setup, so I keep working on that.

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Re: Board design by Ola H.

Post by Ruaraidh_K257 » Tue Jan 15, 2019 8:40 am

Ahh that’s interesting. I’ll need to experiment!! But I guess the trade off of having the super loose setup means it’s harder to go straight for a jump?
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