Hi

I propose this topic as I've had some trifin boards which turn well, but I prefer the grip of the quads in choppy/on wave conditions. I know I should increase the size of the side fins to improve the grip of trifins, but if you do it, the fins must be asymmetric and have some toe in to continue being loose in the turns, and if you include some toe in you add some drag.

I've had some toe in fins but I'm not an expert. However I had two side 13 cm production fins in a trifin board which were asymmetric but no toe in. I haven't seen others like these. I think they were big but didn't need toe in to turn well. Of course trying the same board with 2? toe in fins turned better, but you get less planning performance.

I'd appreciate examples of trifin configurations with similar grip as quads and experiences of big side asymmetric fins with no toe in.

Tsch?ss

Check out Witchcraft, they don't make quad fin wave boards and some of their boards have 14.5cm sides, they also use twisted fins, slightly different to the K4 fins but same sort of concept.

Use the rail more? Here, a stock 17 cm center with 10 cm sides on a 77 L board that has rails that bite quite well.

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Taavi said..
Use the rail more? Here, a stock 17 cm center with 10 cm sides on a 77 L board that has rails that bite quite well.

And for a comparison, the quad setup I am riding has a pretty similar hold and feel in the turns. Nearly 10 L bigger than the thruster above, 9 cm fronts and 14 cm rears, with a narrow chord and pretty small area, the MFC K300 series.

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Sideshore said..
I'd appreciate examples of trifin configurations with similar grip as quads and experiences of big side asymmetric fins with no toe in.

Assymetric fins without any toe-in are effectively toe-out. On the assymetric K4 fins this means that you need about 1 degree of toe-in in order for the fin to be "neutral" when sailing.

I like the AI fins from K4, 10-11cm in length and 1.5-2 degrees of toe-in.

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Sideshore said..
Hi

I propose this topic as I've had some trifin boards which turn well, but I prefer the grip of the quads in choppy/on wave conditions.

You can use bigger asym sidefins without toe, it is just gonna be more hit and miss in the turn entries and generally a more edgy feel. So if you're already into fine tuning the feel in turns, you just gonna have some decent toe in (and I in fact prefer a bit of cant too). With a flat inside asym fin, in total just above 3 degrees is the way to go. The toe in give a bit of a "slip" in the turn entry which delays the moment of grip generation a bit which allows you to set the turn and get in positions before the board kind of locks into the turn. This makes the whole sailing much more free, and you can develop your lines and react to the wave better. 13cm is pretty big for side fins but can work if the conditions are a bit slower. But then I would advice to go much smaller than you think with the rear fin. In particularly if you're not jumping. If you're gonna utilize the side fins for turning grip, you in fact want to kind of minimize the influence of the rear fin. You could for example take one of your quad rears and use as a center fin, ie something like a 14 or 15.

On my Goya Nitro with no toe-in in the boxes i used 13 cm K4 Ezzys with 2 dgree toe-in together with the stock 21 center MFC. Loose feeling and with a lot of grip in the turns and not feeling draggy. And much more spinout resistant than the stock 10cm MFC sidefins.

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Ola H said..

Sideshore said..
Hi

I propose this topic as I've had some trifin boards which turn well, but I prefer the grip of the quads in choppy/on wave conditions.

You can use bigger asym sidefins without toe, it is just gonna be more hit and miss in the turn entries and generally a more edgy feel. So if you're already into fine tuning the feel in turns, you just gonna have some decent toe in (and I in fact prefer a bit of cant too). With a flat inside asym fin, in total just above 3 degrees is the way to go. The toe in give a bit of a "slip" in the turn entry which delays the moment of grip generation a bit which allows you to set the turn and get in positions before the board kind of locks into the turn. This makes the whole sailing much more free, and you can develop your lines and react to the wave better. 13cm is pretty big for side fins but can work if the conditions are a bit slower. But then I would advice to go much smaller than you think with the rear fin. In particularly if you're not jumping. If you're gonna utilize the side fins for turning grip, you in fact want to kind of minimize the influence of the rear fin. You could for example take one of your quad rears and use as a center fin, ie something like a 14 or 15.

I agree 100% with Ola in this... and when i can speak for myself and can add something i feel that quad has more pure grip in the top turn and a thruster set up (with small center fin) is more loose and pivoty in the top turn.
But this can depent from shape to shape end bottom shape...

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Ola H said..

Sideshore said..
Hi

I propose this topic as I've had some trifin boards which turn well, but I prefer the grip of the quads in choppy/on wave conditions.

You can use bigger asym sidefins without toe, it is just gonna be more hit and miss in the turn entries and generally a more edgy feel. So if you're already into fine tuning the feel in turns, you just gonna have some decent toe in (and I in fact prefer a bit of cant too). With a flat inside asym fin, in total just above 3 degrees is the way to go. The toe in give a bit of a "slip" in the turn entry which delays the moment of grip generation a bit which allows you to set the turn and get in positions before the board kind of locks into the turn. This makes the whole sailing much more free, and you can develop your lines and react to the wave better. 13cm is pretty big for side fins but can work if the conditions are a bit slower. But then I would advice to go much smaller than you think with the rear fin. In particularly if you're not jumping. If you're gonna utilize the side fins for turning grip, you in fact want to kind of minimize the influence of the rear fin. You could for example take one of your quad rears and use as a center fin, ie something like a 14 or 15.

3 degrees total or 3 degrees per side?

I've used the K4 Ezzy in 1 and 2 degree. I'd like to try the AI in 2 or 3 to see if they are a bit more efficient for onshore.

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Grantmac said..

Ola H said..

Sideshore said..
Hi

I propose this topic as I've had some trifin boards which turn well, but I prefer the grip of the quads in choppy/on wave conditions.

You can use bigger asym sidefins without toe, it is just gonna be more hit and miss in the turn entries and generally a more edgy feel. So if you're already into fine tuning the feel in turns, you just gonna have some decent toe in (and I in fact prefer a bit of cant too). With a flat inside asym fin, in total just above 3 degrees is the way to go. The toe in give a bit of a "slip" in the turn entry which delays the moment of grip generation a bit which allows you to set the turn and get in positions before the board kind of locks into the turn. This makes the whole sailing much more free, and you can develop your lines and react to the wave better. 13cm is pretty big for side fins but can work if the conditions are a bit slower. But then I would advice to go much smaller than you think with the rear fin. In particularly if you're not jumping. If you're gonna utilize the side fins for turning grip, you in fact want to kind of minimize the influence of the rear fin. You could for example take one of your quad rears and use as a center fin, ie something like a 14 or 15.

3 degrees total or 3 degrees per side?

I've used the K4 Ezzy in 1 and 2 degree. I'd like to try the AI in 2 or 3 to see if they are a bit more efficient for onshore.

3 degrees per side. The AI if I recall is something like a 80-20 profile while the Ezzy is basically a flat inside surf style fin. The AI likes a degree or so less toe in my experience. In fact,I prefer the Ezzy for my type of sailing.

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Ola H said..

Grantmac said..

Ola H said..

Sideshore said..
Hi

I propose this topic as I've had some trifin boards which turn well, but I prefer the grip of the quads in choppy/on wave conditions.

You can use bigger asym sidefins without toe, it is just gonna be more hit and miss in the turn entries and generally a more edgy feel. So if you're already into fine tuning the feel in turns, you just gonna have some decent toe in (and I in fact prefer a bit of cant too). With a flat inside asym fin, in total just above 3 degrees is the way to go. The toe in give a bit of a "slip" in the turn entry which delays the moment of grip generation a bit which allows you to set the turn and get in positions before the board kind of locks into the turn. This makes the whole sailing much more free, and you can develop your lines and react to the wave better. 13cm is pretty big for side fins but can work if the conditions are a bit slower. But then I would advice to go much smaller than you think with the rear fin. In particularly if you're not jumping. If you're gonna utilize the side fins for turning grip, you in fact want to kind of minimize the influence of the rear fin. You could for example take one of your quad rears and use as a center fin, ie something like a 14 or 15.

3 degrees total or 3 degrees per side?

I've used the K4 Ezzy in 1 and 2 degree. I'd like to try the AI in 2 or 3 to see if they are a bit more efficient for onshore.

3 degrees per side. The AI if I recall is something like a 80-20 profile while the Ezzy is basically a flat inside surf style fin. The AI likes a degree or so less toe in my experience. In fact,I prefer the Ezzy for my type of sailing.

I believe my Quantum is ~0.75 degree per side when I calculated it. I quite like the Ezzy 2 degree 10cm on it both as a quad and tri.

I will likely try the AI as a 2 degree fin as well.

I like messing around a bit with fins (inspired by Ola H.). In my almost all of my wave boards, I've had five slot boxes the last 10 years or so.

I tend to use tri-fins in lighter winds and/or a bit more cross-on/onshore conditions and quad in more wind and better waves. I actually use the same fronts for both quad and tri-fin setups, typically 10 or 11 assy fins from Flikka (which I think are really good, I have also give K4 a go). Rear fin is 16 to 18 (tri) and 14 or 14.5 (quad). I like softer and thin rears in a quad, whereas the center fin (in a tri setup) can be a bit stiffer and with more drive. One exception to this is in a bit less powerful waves, where I personally like tri-fin setups more than quad.

The level of grip in a tri-fin setup, from my experience, is also very related to the board you use. My current big wave board, a compact 102 litre tri-fin design, sits fairly high on the water which gives a lot of ease and ability to hit waves also in almost straight onshore. The downside of this is that the grip level is fairly low and you need to kind of "steer" the board into sections rather than carving hard into them. I do not think that a change of fins would alter the low-grip characteristic of the board that much. I would almost describe it a as a bit of a "low grip" all-round freewave board. However, in a tri-fin design I would also try larger fronts and a smaller rear specifically for more grip in turns. The Witchcraft advice seems good, they (Bouke) have been working on similar sized tri-fins for years now, but with a board design that really supports this kind of setup as well. Years ago I tried more of twin setup with a trailer fin, maybe not super grippy but way more fun than thought it would be. Might be time to try that again...

On my quad, 88 litre thing with much thinner tail, the grip and fin story is different. The tri does lift it out of the water more, and you can feel how it pivots more around the center fin, above all in the top turn. But the grip is there, since it is a board designed for more control that sits more into the water. Only when properly lit on a 4.2 or smaller does the quad setup add more control and grip. However, due to the character of the board, I almost exclusively run it as a quad these days.

I would like to throw an unconventional viewpoint into the mix, not to try to convince anyone of my personal preference, but just to keep our minds open. FWIW, my background is surfing for over 50 years, now mostly on smaller high-performance SUPs, and wavesailing for 40 years living in Hawaii and Baja.
To understand this viewpoint, let's review a little fin history from my first surfing experience in the 1950s: The earliest longboard single fins had a ton of chord which gave the directional stability they needed but were hard to turn. They then reduced the fin surface area, especialy the chord, which improved turning while still retaining plenty of grip and drive, partly due to the sharper rails. Then Mark Richards popularized twin fins which were mounted more forward and closer to the rails producing tighter turns but with less drive. Simon Anderson then popularized the thruster set up which kept the tight turns of the twins with added drive from the trailing fin. In my current experience, the best performing thruster setup on my small performance SUPs, somewhat comparable in size to a windsurf waveboard, is medium sized front fins (4.5" to 4.75") with a smaller (3.75" to 4") trailing fin to add drive. If the rear fin gets to large, it starts to fight turning around the front fins and the board gets very stiff. It is important to note that I find this combination works best if the rear foot is placed directly over the front fins, whereas in windsurfing, the rear foot is placed over the rear fin(s). The key point here is that thrusters in surfing are based on twin fins with a trailing fin added for drive. The exception is the 2+1 set up on some longboards which is basically a single fin with small sidebites added, what we would call a "thruster" set up in windsurfing. Unlike twin fins or true thruster setups which turn off the front fins with the rear fin acting to add drive, 2+1 setups turn and drive off the primary center fin.
Now on to the original question about adding drive to a windsurf tri-fin. Unlike in a surfing thruster set up, in a 2+1 windsurfing "thruster" setup, the board turns off the primary center fin and the sidebites can help or hurt that depending on things like placement, toe-in, and cant. However, if the side-bites get too large, they will start conflicting with the turn and drive from the primary center fin. This is why the best way to loosen up a windsurf thruster set up is to move the front fins back closer to the center fin which is under the rear foot, or just make them smaller so they won't conflict as much with the turning and drive power of the primary center fin. If you want to add more grip or drive, start by adding surface area to the primary center fin placed under the rear foot. Using a smaller center on a windsurf board does allow for better lip slides and rotational maneuvers when you don't want the center fin to catch or grip too much. For myself, I always prefer bottom and top turns that maintain grip and therefore generate speed and drive around the turn rather than losing drive during a lip slide, but that's just personal preference.
In regards to the original post question, I find that, for me, the best way to add grip to a windsurf tri-fin is to add surface area to the primary center fin, not larger front fins as I would do with a true thruster setup on a surfboard. Just my own experience.

What fins?
What board?
What sail?
Where do you need more grip (bottom, top, etc)?

Tris have more drive and fastest speed.
Quads have less lift, sharper turns, most spin out resistance and controlled slides.

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obijohn said..
I find that, for me, the best way to add grip to a windsurf tri-fin is to add surface area to the primary center fin, not larger front fins as I would do with a true thruster setup on a surfboard. Just my own experience.

I agree with a lot, if not all, of this. Only thing I would like to add is that changing to a more upright center fin, or a grippier design, can also change this quite a bit (without adding surface area). One thing that I personally struggled with for a while was to get my tri-fin setup to work as I wanted. I quite often felt that it ended up being too directional and not very adaptable on the wave. The main thing that changed this, for me, was to go for assy front fins and reduce the size of the center fin a bit. So, I went from something like 18-19 center fins and 8-9 sidebites to 10-11 assy fronts with 16 or 17 center fins in my 85 to 95 litre boards. These center fins are, typically, thinner and more swept back (less grippy) than what I used to have in my initial outings with tri-fins.

These days, I mainly ride my big wave board as a tri, and my small as a quad.