Having some trouble cleaning out the middle of my swallow tails properly. My routine starts like this. Cut the swallow tail in (straight swallow not rounded like a fish). Use bastard file to make a ramp up the middle and this is where the fun starts. How do you get at the stringer that hasn’t been ramped without taking hacks out of the foam? Should my ramp start at the very bottom of the board and end at the top with some rounding off for good measure? I bring my sanding block from the centre out but I’m ending up with a triangular section left in the middle if you know what I mean. Would someone like to share their routine so I can do it right?
A Dremel tool with a cut off wheel can be used to cut into the stringer from each side - try to meet the cuts exactly in the center and pull the wedge out. With Dremel held at just the right angle you can get it close enough for a triangular or rat tail file to finish off the stringer. A thin flat piece of wood wrapped with sandpaper can be used to whittle the foam down to match the stringer. It’s easy to gouge the foam on either side of the inside cut so take your time and don’t mess up. I try to get them to look something like this…
I use a coping saw to get the “ramp,” then go to a thin round file to get the final shape. Using the tip of the file, I’ll gently cut a groove into the stringer, and once that starting groove is cut, it guides the file so you don’t slip off the stringer and into the foam. But you still need to be careful. Anything left, like that perfect Vee at the bottom edge, gets cut with the corner of a razor blade. I just take my time and go at it slowly when I get close to the end.
Forgive the double entandres and inyourendos that follow butt…Does a tight buttcrack really make all that much difference. Sure it looks nice and shows the tallent of tool usage. Butt in the end, when the glasser takes over, its all about the mashing the diaper in tight and sanding a sloppy hotcoat…
Since I try to glass my boards, I’ve learned to love the wide round crack, just wide enough to, say, wiggle your finger around. Or maybe go with the pulled apart cheeks like Griffen does with his. Fast, easy, even pleasurable to perform…That’s my motto!
This is a design point I think is worth discussing.
The bigger around the radius of the taint, the more water is released further up the board. A tight crack releases less water. So it’s worth thinking about the shape of the crack. I actually use a formula to create my fish tails, because I believe it deserves the attention, and makes a difference in performance. More crack means less lift and deeper rail penetration on a turn. A tighter crack and smaller taint means more square inches of planing surface. This is not a subject that’s talked about much, but I think should be.
So…Does the shape of the area removed make a lot of difference? That is; given a identical planshape, and equal area of swallow tail, how does a wedge shaped cut compare with the curved version? I know that the more area removed, the more forgiving a wide tailed board becomes. You can put your foot over the fins and keep the center of effort in front of the fins. I just believed that the wider the tail, the more area you had to remove. What’s your secret formula???
Great question mate, i’m keen to hear this, some great ideas so far.
Thanks. I’d like to get my swallows looking like Greg Griffins which to me look like a single ramp on either side of the stringer from the bottom of the board to the deck. I’m guessing this requires a different approach to a fish tail with a narrow butt crack which looks like it should be set up like a rail with bands to be blended in?
When I tried to set it up “my way” I end up with a ramp that had it’s top end half way up the deck and a quarter inch flat section under the bottom of the ramp. Obvious thing to do is to change the angle of the ramp but then I ended up with a ramp that was near vertical.
Can’t seem to get my “ramp” flowing into the deck and bottom smoothly on a single angle (not 90 degrees) without the top end of it ending half a mile up the board. Maybe I made the tail to thick? Maybe I would to better off making two ramps and two bands and keep it that way instead of trying to get a single “wedge” on each side of the stringer.
I believe the shape of the tail has a lot to do with performance. Not so much the mini swallow, but the true, deep crack fish tails. I don’t mean to hijack the thread, but…
Greenlight Brian will put something out soon about fish tails in his design notes, but here are a few excerpts. I hope this starts some pithy discussion:
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It’s helpful to think of fish tails in one of two ways… retro fish type tails (like Pavel’s tails), and shallower tails that are still fish tails, not mini-swallows (MR Flying Fish, or the Rawson Twin Fish).
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The former removes about 14% of the area of the last foot of board and produces a ride that’s true to the real “fish feeling” of retro fishes. This design allows the shaper to maximize tail width and straighten rail templates behind the wide point, while reducing planing area, increasing responsiveness, and improving hold in steep portions of the wave.
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The second produces some added curve in the rail line through the tail, and a smaller, shallower swallow, moving the design toward the true “twin fin” designs that came after the first fish movement started by Lis.
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Straighter lines in the deepest part of the crack provide greater and more even release than a continuous curve carried from the stringer to the tip. The more release, the more responsive the shape, as water is allowed to quickly exit from under the board down the middle, shifting the center of the turn’s axis toward the rail. This allows the tip to penetrate slightly deeper, improving bite and hold.
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Fuller tip area provides fin-like projection through the turn, as more water is deflected by the relatively larger surface area.
Tweaking the design so that the inside curves of the fish tail are combinations of both straight lines and curves, thereby controlling lift and release, allows you to play with the design and specialize it for a particular rider or particular wave. Tip area is the key, I think, in how a board rides, and that’s determined by the inside curves, tail width, rail line, and depth of crack.
"Forgive the double entandres and inyourendos that follow butt...Does a tight buttcrack really make all that much difference. Sure it looks nice and shows the tallent of tool usage. Butt in the end, when the glasser takes over, its all about the mashing the diaper in tight and sanding a sloppy hotcoat...
Since I try to glass my boards, I’ve learned to love the wide round crack, just wide enough to, say, wiggle your finger around. Or maybe go with the pulled apart cheeks like Griffen does with his. Fast, easy, even pleasurable to perform…That’s my motto!"
It’s all about the bottom…
I think bottom design through the tail is an important factor in designing the tail. For example, if you’re using vee, which tends to let the tail sink down deeper into the water than say a concave, you might want to have a curvier crack to hold more water under the board for longer, providing more lift to compensate for the deep vee. If you’re using concaves, like pavel does, you might want to straighten the crack curves to provide some extra release.
Does this make any sense?
I’ll buy the effects but maybe not the causes…Follow me on this;
Tails of equal width and outline, depth of swallow cut equal. What am I going to feel different between a curved cut and a straight one?
I believe you will feel the difference.
The point I tried to make in the other post was that you can add a significant amount of surface area, and change the pattern of release, by adjusting the inside curve of the fish tail. Straighter lines mean earlier and more even release, while more curve adds surface area and lift. Because it’s behind the back foot, even moderate amounts of surface area can be leveraged considerably.
I also agree with your emphasis no fin placement being key. I mention this as well in the design notes that Greenlight will put out soon. But I didn’t mention it here because I wanted to keep the thread focused.