Rusty Surfboards

This is a fantastic article by Rusty himself.
Which gives you a clean and easy to understand outline of what tail works in what waves and how. So when your looking for a new board or an idea for your new custom shape. Give this article a little read. Boardshop have all the latest Rusty shapes in stock. With new shapes and stock arriving very soon. Including the all new Rusty Dwart. If you also want a specific tail profile and rocker line let us know and we can speak with boardshops own local UK based shaper Matt Adams to work his magic on your dream blank! Rusty Surfboards.

Square: Probably the grandfather of all tails, maximizes rail length and area in the last foot or so of the board. It adds stability, drive, more angular turns, quicker release, and less continuity in rail-to-rail transitions. They are used by some shapers as a small wave design and were used by some shapers in early big wave designs — gun pioneers like Pat Curren used small square tails on guns.

Fish Tail, Swallow Tail, Dove Tail, Split Tail: A square tail with area removed between the corners, fish is a catchall name. Split tail is a name that doesn’t initiate semantics debates. Fish used to be a wide (10″ to 12″) split with a fairly deep cut about half the width number. Quite often, shapers will use a round pin template to create the inner curve. Swallow was a used on more of a standard hotdog type board with a 5″ to 7″ split. The depth was an inch, give or take and the inside cut had curve. A Dove tail was similar width and a little shallower depth with a straight inner line. Width, depth of cut, and area (fullness of curve) of the inverted pins can be used to achieve different riding qualities.

An interesting sidebar on splits with deeper cuts is they promote flex. Plenty of shapers over the last few decades have experimented with thinning out the pins to the point where they are virtually just fiberglass.

Baby swallows or baby fish tail refers to a narrower tail on a gun with a split that maybe as small as 3″ or 4″.

Squash or Rounded Square: Here’s where we start getting into semantics and hair splitting on the names. Maybe a squash tail is a round pin someone dropped and a rounded square is a square that had its corners sanded off. Basically, they are both shaped by rounding off the corners of a squaretail. In addition to the usual checkpoints, I track numbers 1″ up from the tail and 6″ up from the end of the board. An average squash tail is about 10 ½ wide 6″ up. The 1″ number reflects how much curve there is because it’s difficult to measure the end of the board unless it has distinct corners, like a fish tail or a square. An average squash is somewhere in the 5 ½” to 6 ½” wide at 1″ up.

This is probably the most common small/medium wave tail shape. It offers a nice blend of area and curve. It became the go-to tail shape when three fins took over the world in the early 1980s. There were wide squash tails built early in the shortboard era. The problem with wide tails on single fins was that the wider the tail (block) the deeper the fin needed to be. The deeper the fin, the more the frontal drag. With three fins, it really enabled designers to go wider and shorter, moving area aft because of the hold and drive three fins brought to the game. The tail shape provides lift, support, and drive.
The balance of release and smoothness or continuity depends on how rounded the corners are.

Diamond Tails: A blend of round pin and squash with the corners moved forward a bit maintaining area, shortening the rail, finishing with a subtle point, and a very clean exit for a board with some tail vee. Diamonds were used quite a bit in the early 1970s on a wide range of boards all the way up the ladder. A nice blend of aesthetically pleasing yet, still very functional.

Bat Tails: Take a squash or a diamond and invert the last inch of the tail. I did ‘em in the early 1980s. They are all the rage for quads now. The area removed and little corners add some bite and help give the boards without a rear fin in the middle a little extra drive.

Round Tails: Uber-smooth turns. Make a clay model of a hollow wave, use a wire to slice it along the speed line in the barrel, and the cross section will probably look something like this. Or Google conic sections. This tail is a clean, natural curve that fits the pocket. It’s a great tail for a performance shortboard, good in head-high to double-overhead waves. Also, a good option for next one-up type shapes.

Thumb Tails: Look like the tip of your thumb — a blunted round tail with little less curve between front and back fins. Area in last few inches can vary compared to a roundtail; a little less than a squash tail. It’s an excellent all around tail shape with the smooth transitional qualities of a round tail and a little bit of release that you might feel in a squash. Combined with a slight hip or subtle bump, it makes an excellent tail for everyday conditions and into the good stuff. Probably the second most popular tail, behind the squash, for performance shortboards.

Round Pins: Are typically used on longer boards for bigger waves. As the board gets longer, the curves get stretched out, it becomes a bit of a juggling act for the designer to maintain a balance of curve and area.

A tail that is too narrow sits too deep in the water, compromising the board by creating unnecessary drag. A tail too wide creates the opposite problem.

Once again, remember that rocker, fins and foil all come into play as well.

With 1970s style single fins, the wide points up, long rail lines in the back, and pinny pintails (low area) were necessary to keep the tail in the water in bigger surf. Tri-fins allowed designers to go a little wider and use more rocker because of the hold and drive created by the three fin setup.

With quads, it opens more doors.