is there a minimum measurement to tail width that will work best as a quad? and why? is it that quads require a wider tail or that a wider tail prefers a quad setup? i am wondering as this applies to a short, performance intended board, say 6’0’’ to 6’4’'. does it have to do with fin engagement when the board is on the rail?
brasco
The short answer to your main question is no. The amount of 4-fin guns out there kinda takes care of that. A ''performance intended'' quad doesn't need to have a wide tail.
To that I would just add, “…well there you go.”
Actually I would add that while there may not be a minimum, there are some limits to the maximum. Mike has forgotten more than I will ever learn about this, but I’m thinking 15 wide is getting pretty wide.
It seems to me that wider tails were once conventional wisdom when it came to quads. That’s changing. While a lot of small wave quads stil have wider tails, I’m seeing lots of performance boards with “normal” tail widths these days. A quad setup on a board designed for summertime slop with a 15 inch tail is works great. Take it out in head high waves and you start to lose the advantages, even moreso than you would on a thruster. What I’m saying is that a tail that’s too wide with four fins works worse than a tail that’s too wide with three. The new “conventional wisdom” that seems to be arising is that what matters most is the distance between the rear fins, not their distance from the rail. Looking at that development, it’s easy to see why tail widths are coming back down to “normal.”
I’ve made a bunch. It really all depends on the application. My feeling is if the waves you are intending to surf the board in require speed changes, then thin narrow tails you can step on to slow down. If you want to go faster and not have as much braking control then go wider.
All my experimenting has been base lined on years of riding trifins from great shapers. I feel like a lot of people are trying to get there quads to “go as good there trifins”. So the reaction is to pull the two rear fins in were the single rear on a trifin would be and narrow the tail.
But, I’m obsessed with the speed a wide tail and fins on the rail produce. It’s like skateboarding on waves. I’ve let go of the benifits of trifins in exchange for speed. I can get trifins going but it requires a lot of pumping. Pumping turns into hoping and wiggling which isn’t my favorite way to surf. Trifins hook in the pocket, so stalling for tubes is much easier. And, they go vertical up and down in the pocket much better than quads. Quads outrun sections, so peaky beach break can be frustrating.
In short, push your quad tail and fin specs towards trifin specs if you want the boards to act more like a trifin. Otherwise go the opposite direction for a twinfin feel. I keep my front fins in the same spot on both trifins and quads. Its the rear fins I adjust. Somewhere in between will be a sweet spot that suits you, or quads may not be your thing.
Josh
Monkeyshines - good info.
How do you think they handle on the foam ball? One of the disadvantages of quads, particularly the wide-tailed versions, is their inherent instability on the whitewater… either back in the tube or rebounding off a cutback. Bottom contours can help mitigate it, but compared to thrusters, quads are much more unstable.
njsurfer
i am curious as to why a thruster would be more stable than a quad in the whitewater? you hint that it may be due to increased tail width…but the question seems to indicate that it due to increased incresed fin area
brasco
Yea… I do think it has to do with both, with all that turbulence and chaos under the board. I think that the added tail width naturally makes it more unstable, but the extra fin as well. Like you said, more fin area = greater instability in the soup.
But even more than that, the fact that the fins are closer to the rail means that the instability is felt even more than if the fin was on the stringer, centered behind your back foot, where the force creates less rail-to-rail leverage (for lack of a better term). With fins apart and closer to the rail, the turbulence can act on each fin independently - there might be downward moving water under one fin and upward moving water under the other. Under this condition, instability is increased through increased rail-to-rail leverage - another reason why I think bringing the fins closer to the stringer helps performance. McKee’s placement formula does this to a degree.
Some other famous shaper here likes that double trailer. Who is that??? I’d like to know how that setup goes on the foamball.
My belief is the lack of a trailing fin causes the instability. On my thruster when I go to a smaller trailing fin I can feel the board have more unwanted lateral movement. Concaves are also less stable going straight in, in white water than v bottoms.
I don’t care because I’m so far down the line there is no foam ball.
The speed gained keeps my fins in the water less and in the air more, and flying through unmakable tubes is all made possible with the speed from quads. I fly over crumbling sections, and make figure eights with out the drag from a center fin.
All without having to wiggle. I don’t care about the quantity of turns on one wave just the quality.
Boggie Boards go great on the foam ball.
How you quantify any of my claims is beyond me, but that’s my take on the matter.
I’m just teasing…
fin area : tail area and fin placement
What I'm saying is that a tail that's too wide with four fins works worse than a tail that's too wide with three.
I have found the opposite. The beauty of the four fin is that it allows you to ride a wider shape wiht flatter rocker in way bigger waves than a thruster setup would allow. So you have the blistering speed from increased area and flatter rocker but the 4 fins keep it under control where a thruster you would have no control.
There is no minimum or maximum tail width for a quad - it all depends on what you want the board to do. They work well from a tiny fish to a huge gun.......
We had a suprise last weekend, and the swell jumped from waist/chest to 3 or 4 feet overhead on set in a couple of hours. I had my trusty wide-tailed (almost 16"), low rocker quad out, and felt like I was barely holding on. Maybe it was just me, but I was definately on the wrong board. Blistering speed, yes. Sense of control, absolutely not. Granted, there’s more to it than just tail width - fin choice, rail profile, tail thickness… all that stuff, too. But I would have to say that the tail width was the critical component that turned what could have been a dynamite session into a total struggle. That board was designed for performance in under head high surf, and it works great inside that envelope - sort of a battail quad version of a Mod Fish.
Maybe this is turning into a “maximum tail width for quads” thread…
well, there you go.
well a 16" wide tail in overhead surf (if it is hollow) is a challenge with any fin configuration.
the question is - would the same board hold better as a quad or a tri? and how big of a wave will that same board hold if ridden as a quad or a tri, my bet is that the quad setup would surf better in a larger range.......
really a tri fin on a 16" wide tail board would ride like crap no matter what the waves.......
I have only been able to overcome the tail width issues on super wide fish shapes with a deep swallow cut into the tail. I’m really just removing planning area, and deep swallows tend to stick on tight top turns. So, then I move toward shapes that look more like a shortboard. This really is a fish vs shortboard problem. I trade one problem for another hybridizing quads. The round tail quads that I have made(narrower tails) all worked better with smaller fins.
There is a threshold where no amount of engineering is going to make a widetailed quad work in large hollow surf. You have to move towards a narrower plane shapes.
I have some diff fins that really allow my wider tailed quads perform and handle much beter.....
Right. The question is, which would have worked better… a wide-tailed quad, or a wide-tailed thruster. I don’t see any logic to a quad working better than a thruster, but I do see some logic to the opposite - less fin area might mean a bit less speed and a bit more control. Combine that with a overly wide tail, and you’re not only a sikipping stone, but in an effort to get that fatass over on a rail, you end up harnessing all the power four fins give you, and oversteering - everything else held constant. Every twitch turns into a slash. And that’s what we’re talking about… changing tail width alone, not fins, rocker, bottom contours, etc.
Don’t get me wrong. I’m a big fan of quads. Except for my longboard, that’s all I ride these days. Even my big wave board is a quad, and it works great. But it’s got a narrower tail and different fins.
so lets take two 5'10s out on a well overhead day - a thruster with a 15" tail and a quad with a 15" tail
you think the thruster will handler better?!
any wider of a tail and a thruster is not a very good option - twins or quads win out easy (why do you have a quad setup on your 16" wide tailed board anyways - try surfing that thing as a thruster - i bet you will not keep your opinion about wide tails and 3 fins working better)
but alas i could be very wrong and just blowing smoke
that is why surfing is great - what one person thinks is the right way to go is the opposite of the next persons............