it’s also interesting how that type of buttcrack features chamfering on top that’s sharply angled, whereas most butt cheeks are rounded off topside.
in any case griffin’s 5-fin setup got plenty of raves in other threads, with one saying that his bonzer was going to be sidelined while he’s enjoying his griffin 5. i’m assuming it’s a 5-fin bonzer but either way, both boards seem to elicit rocket-ride testimonials-- which point to their individual design credentials (griffin’s flat bottom with sharp rails & the campbell bros. bonzer’s concaves-with-fins setup)-- regardless of planshape.
this finding swings the fishtail buttcrack argument to the side of those who say that it’s really nothing but artistic flair. hmm !
In my opinion the main function of the cut out of the tail (and LeeV touched on this), is to balance the lift provided by the fins with the lift provided by the effective (that which is actively creating lift) hull.
If you have too much tail area behind the fins, then you will get a windshield wiper effect; the tail creates too much lift, the fins become less engaged. As Pro-Box Larry has described, "the tail overcomes the fins".
There are other ways to fix the problem, besides cutting out the tail, like adding a trailing fin, or moving the front fins back. But like everything else in surfboard design it is a balancing act.
Surfiber, Greg used to post under the name Chandler. I think it was because he was still working for T&C. When I met him he was having issues with T&C allowing him to build these types of boards. He was T&C’s longboard designer, and that’s what they wanted him to build. Shortly after that T&C decided to let Pang have it all and let Greg go.
Luckily he had already started working on these boards for us and was able to start his own company. He had a rough start, but my brother says he’s doing OK now. My brother gave me a thruster he got from Greg, but I haven’t tried it yet. Greg said his thruster would be better than the 5 fins.
Greg’s fish uses flat bottoms, tucked under rails with an edge that starts way up about a foot from the nose and runs all the way to the tip of the tail, thinned out rails about the size of a quarter. That’s why I said to look at the crowning of the deck. These boards will glide along on 1 footers and carve up double overhead waves. I like the older fish shape versus the newer modfish with a pulled in nose. Seems like it has more drive with the wide point a bit more forward.
Greg’s buttcrack is the first I’ve seen like it. I think it’s about 1 1/2 to 2 inches thick at the stringer, and flat to the rail.
The “lobe” I refer to has to do with the end of the tail… the tip… specifically the inside curve leading to the tip. The crack starts straighter at the stringer, and gradually accelerates toward the tip, creating a “lobe” shape. A pointy tip, with less surface area, penetrates the water easily on a turn, offering no resistance to the pressure applied with the back foot. The lobed tail tip, with it’s added surface area, deflects more water, allowing the tail to bank more and penetrate less. This lets you hold more speed through the turn, even on softer or smaller waves.
The keel fins I use are single foiled, but with very little toe and cant, so they offer very little lift. My bottoms are slight single to double concaves right out the back. There are no hard edges at all. Look at Pavel’s fish. They’re a lot like that too. I think Pavel’s twin keeled Rainbow Fish is the best “retro” fish you can find today. The subtle changes to bottom contours and rails, along with the refined tail geometry and ratio, is what make it so, IMHO.
board design being a balancing act like you say, wouldn’t it be more economical for shapers to reduce the tail area behind the fins the way simmons reduced board length and then pushed his twin fins further to the corners, with no further planing area and lift to deal with behind those fins?
because if we are to admit that precision shaping & glassing of fishtails is worth the ride that fishes promise since they started becoming popular in the 70s, then by now there would’ve been only 3 to 5 buttcrack templates at most, as well as more commonly-known geometric formulas to shape them, the way there are accepted fin setup formulas for thrusters, bonzers, griffin 5s and simmons twins that work no matter what, wouldn’t you think?
the diversity / variety of split-tail boards today only highlights the differences that persist in how this design progression is understood & pursued hmm
what i found interesting in the pics from the other thread was how greg’s volume distribution (as well as the rocker & planshape) looked so subtle, no discernible feature actually stood out apart from the rest (except for the 5 fin cluster/setup).
just wondering, if the back foot is to be placed right above the rear fin cluster for bursts of speed, would the effect be any different if the shallow buttcrack was not chamfered but rolled? just thinking out loud here since the chamfered angles resist flexing, unlike a sloping/rolling transition from deck to buttcrack.
with respect to this 2 main fishtail templates, where do the bat-tails & crescent/moon-tails stand? or are these next 2 simply squaretailed boards with artfully-modified tailtips, given that the reduction of tail planing area on them is nearly negligible?
Ben Shipman is no longer with us but I grabbed a whole bunch of photos from him before he died. I can't explain what's going on but I can pass on the stoke!!!! ......and I glassed a handfull of Shipman surfboards....
how about ride reports, ray? sweet pretty buttcracks all in a row! lol
cheers,
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I am programed to post pretty pictures. If you want well informed answers to complex questions you need to talk to the people that posted without photos. LeeV is a good source. Everysurfer is good. SharkCountry and NJ are really good too. I'm more in tune to glassing not so much design....
Look for the "gun" inside the Shipman Fish....Let me know if you see it. Shipman's art Blows my mind!
