Advantages/Disadvantages?

get a swallowtail

 

squash/square tails pivot better & change direction very well. this is why most high performance boards have those types of tails.

round/pin/round pin tails handle high speeds very well & tend to prefer smoother, longer arcing types of turns. this is why your some of your step-ups & your semi-guns/guns have this type of tail

in my estimation, a diamond tail is nice combination of those 2 tails.

a swallow tail is cool b/c it shortens the rail line of the board, so you have a shorter board w/ the volume of a bigger board. depending on the width of the swallow tail, it can act in a manner similar to a squash or a pin. you'll sometimes see tiny little swallows on some guys big wave boards.

personally, i prefer round pins on my boards. i've had a couple good diamond tails & 1 or 2 good square tails, but the overwhelming majority of the boards i have in my quiver today have round pintails, as have many of my favorite boards of the past.

 

almost all my high performance shortboards have a rounded tail. I had ridden mostly squash and square tails before that, because my shaper explained how these tails promote more water movement during direction changes (i.e. bigger spray through turns)... But for over-all performance, I have fallen in love with the rounded tails. They allow perfectly fluid turns, even going 200mph. I can feel a HUGE difference in the ease of turning at high speeds with round tails compared to squashes.... A few years back, my friend had a Fish that had a round tail, and the thing was PIMP! You could get into DOH mushy reef breaks, but then turn on a dime on a top turn and change direction...

So, on all my boards, I prefer the round tail.... I understand why some guys like the squash, but it doesn't do anything for me really. My 6'2 and my stepup shortboards have squashes, but I use them in bigger surf so I don't really feel that much of a difference, because the turning arches etc. are long and smooth anyway.... But I feel like a simple tweek of the ankles while riding the round tails allow the board to response much quicker, allowing for quick precise turns...

Im no board techie, I am just speaking from riding them... I really have no idea what the technical sh** means, but I know my turns like about 12-15% better on a round tail than a squash while in normal chest-head conditions.

 

All of what you said is right on the money. The only thing I have to add to that is to clarify the swallow/rail length statement. Whether the swallow is pulled (mini swallow or a notched swallow) or wide, from tip to tip (a true twin fin swallow or fish tail) will determine whether they lengthen or shorten the rail line. The former will shorten what I call the "effective rail" while the latter will lengthen it, taking a straighter rail line all the way to the tip.

Generally speaking, a curvier tail outline (round. thumb, round pin...) shorten the effective rail, as the template is pulled into the curve. A straighter tail outline, like those leading into a square, squash, or rounded square tail, will lengthen the effective rail, taking it all the way out to the corner of the tail. But there exceptions... bumps, hips, wings, etc. change the story.

The rule of thumb is... square tails, square turns... round tails, round turns.

 

good point...i should've clarified that myself.

 

more surface area=more loft.

however

squash/square tail=better release/less water adhesion, so quicker out of the wave on the launch. this is probably more important, which is prob. why most pros & air guys prefer them over most other tail designs, except the swallow tail.

 

Yep... and hard edges. A touch less tail rocker seems to help, too.

 

on an longboard tail rocker is your friend

 

If we were in Italy, I'd have to make your bunk...but we're in Germany, so you have to make mine.

 

Agreed. I'm not too great at boosting airs, but I've definitely noticed that my squash tail is MUCH easier to throw around, especially in small stuff. My round tail is a little bigger, but it definitely is more of a "flow" shape, as Zach was saying before. My opinion is that a round tail is generally better for quality waves. If it's big or if I'm trying to go get barreled, the round tail works far better. If it's small or I'm trying to do airs, the squash offers more maneuverability.

 

i love a swallow tail for most conditions, except like everyone said clean overhead barrels. i would like to try a 6 channel roundpin though for my next semi gun or bigger step up.

 

Channels are a fun design concept and can do a lot for performance. They're used mostly on small wave boards, when you're trying to eek out every bit of drive and speed in small surf, weak or punchy. They hold great in steep, small beachbreak surf. At one time, my favorite board was a 6 channel.

Be careful about getting them on a board intended for powerful, overhead surf. In big waves, they have a tendency to become tracky, so you have to compensate for that by pulling in the tail, using smaller fins, or adding a bit more tail rocker. The other thing you can do is make the channels themselves shallower or shorter, or both... through the tail only... if you're putting them on a step up.

 

good thread going here.

any opinions on bat tails? never ridden and they look interesting. i'd imagine it'd be a lot like a swallow...

 

You know what they say about opinions, right? Ha! Well, here's mine, for what it's worth...

You're right... bat tails, along with swallows, crescents, stars, and other "cutout" tail shapes are similar in that they all (1) remove surface area (which means planing area) adding control and release from along the middle of the board, rather than from along the rail, like a rounded pin, or diamond tail. The more surface area removed, the more bite and control in steep parts of the wave, and the more control at speed. So a bit of foam removed to make a bat tail will provide the same release and control as a swallow, but to a lesser degree because less material is removed.

Bat tails also (2) maintain a straighter rail line through the tail, lengthening the "effective rail" all the way to the tips. Rounded squares, squashes, round tails and diamonds shorten the effective rail to different degrees by rounding off, or eliminating completely, the last few inches of rail before the end of the board (at the stringer). So in terms of the the flow of a board's overall planshape, it's easier to lead a smooth, flowing curve through the middle of the template into a curvier tail shape. A straighter template through the middle more easily transitions into a straighter tail shape... a bat, crescent or square tail.

So a bat tail allows you to maintain a straighter outline through the middle and back third or so, while still providing you with some reduced surface area in the tail block for control and release.

 

LBCrew's got it down.

too little blurbs from interviews with Matt Biolos (...Lost)

What is the single most important design element on a surfboard?
Most important is the rocker – the amount of bend. And secondary rocker which is how you blend the rocker with the outline. Balancing the curves between the rocker and the outline, actually, is the most important design element. I try and keep everything else static. Same fin, same fin placement, same rails. That’s the way you really figure a good board out. Good surfboard design has always begun and always will begin with the rocker – any shaper will tell you that.

Which explains why these short 80’s outlines are working so much better today. So what’s the least important element?
Tail shape is least. You basically have either some sort of rounded tail or some sort of chopped-off tail. So a squash, a swallow, a bat – they’re all basically a long, straight line that abruptly ends. And then a roundtail comes to a curve that consequently shortens a rail line. Think about it: You could take a fish-style tail out in solid waves, and if the overall board is designed for solid waves it will work.

Read the rest of the interview here

3.Tail shapes don’t matter as much as you think. If the width going into the tail is the same, a square, a squash, a diamond or a swallow is going to behave in a similar way. Round tails and pintails decrease the rail line, so they’re going to hold a little better and shorten a turn radius.

Read more from Stab’s guide to surfboard design for dummies

 

beat me to it! that's one of the best straight-forward, "putting it in layman's terms" articles i've ever read about shortboard design. everyone should read it.

 

the Allen Byrne deep 6 channel bottom is totally misunderstood because very few people can shape a channel bottom correctly.
Doerner tows in on Byrne's deep 6.
Scott Busbey, In The Eye, Hatteras, shapes channel bottoms correctly, any board for any wave.