Hi there,
I’m currently in the fantasy proces leading up to the building of my third board, which is going to be a small twin fish for stormy, short period North Sea surf, so small waves up into the overhead range.
Having happily surfed a 5’10 CI Biscuit for many years, I have some adjustments I’d like to make to better suit the conditions in Dutch waves that generally lack power and are very choppy when bigger.
I want to make the rails a lot thinner as opposed to the bulky Biscuit. To counter this loss of volume I want to widen the overall outline a bit and instead of a rounded pintail make it a fishtail to maintain speed coming out of turns.
Now here comes the question
Could/would shaping a (big?) vee in the tail help me translate the smooth rail to rail transition of a rounded pin to a fish shape or? Or am I going to slow the board down too much and lose all the fun and speed that come with a classic fish shape?
Love to hear your opinions!
Rik
Haha ok that answers my question then
Was hoping to stay away frombthe oldschool fish a bit and try to make it a bit more of a hp carver, but guess the old guys allready figured that out long ago…
Another question then, whats the difference between vee and a double concave? Cause I allways thought double concave was more modern and faster as opposed to vee, or am I missing something (again)?
As far as I know, the Retro Fish is a “flat” bottom going to Vee at tail (Vee has flat sides like a V).
No concave(s) involved.
Pretty sure flat bottoms are the fastest (least drag/surface area).
I think if you listen to some of the firewire promo videos they reference Dan Mann talking about how a V is added to the tail of some of his shapes to allow for more responsiveness with a WIDE TAIL. The V contour helps the wider board turn over to initiate a turn (like a boat hull helping a boat arc and turn while at speed). Classic San Diego fish would want the V as it typically has a wider tail (compared to a Mark Richards twin w/ a pulled in tail). As I understand it, once you move away from the potato/buscuit wider templates to a narrower template you can move away from those helper features and favor double concave. Of course V gets more complicated if you’re talking about a V inside a channel (like some of the more modern shapes that I think Ryan Lovelace is doing w/ his “pedestrian ship” shape). There are obviously more subtleties than a newb like myself could explain adequately. Hope this helped in some small way.
The “pedestrian ship” is a variant of the surfboard “Venturi Channel,” neither is deep enough to function as a Venturi Channel. Similar to the surfboard “Torus Channel.”
Vees in certain channels neutralize the advantage of the channel. And can increase drag.
In the YouTube video I posted Ryan Lovelace discusses and shows the twin fin with V that he developed with William Aliotti, it has a different bottom than the other twin fin boards shown here. No channels. Its worth watching the video, as he discusses and shows the design being shaped, as well as the board being surfed.
The venturi effect in surfboard design has been debunked, as you need a closed or constricted area for the water to pass through, i.e. like a pipe or tube. Channels on a surfboard are open, so the water will not compress. Not saying channels don’t have a purpose (obviously they channel the water) its just that venturi is not it. This goes back to the initial bonzer theory. Bonzers have since dropped the venturi reference, but they still retain the channels.
I watched the first 9 minutes of the video you posted before ny comments. The Vee I thought I saw was very slight.
I am still of the opinion that “spiral vee” creates drag.
I don’t disagree - V is about control not speed, facilitates changing from rail to rail. Like a fin in that sense (gain control at the sacrifice of some speed), both create drag.
Greenlight provides the most extensive discussion about bottom Vee. The diagram for Panel Vee isn’t very useful. Panel Vee or just “Vee” has flat sides from ridge point to rail (increasing rail rocker in the tail) according to George Orbelian — IMO the Vee ridge-line improves tracking and the increased tail-rail rocker augments turns.
However, I have observed what some shapers are calling Spiral Vee (e.g. Lovelace F/M) to be be a wedge/delta shape Vee that starts as a point and then flares outward toward the tail — more or less triangular (as viewed from above) with the Vee ridge running down the center — in a word, drag.
Spiral Vee according to “Google AI”
(Love it, I’m quoting a computer.)
A surfboard’s spiral vee is a bottom contour that combines a vee shape with a concave, with the vee becoming deeper as it moves from the front foot toward the tail:
Spiral vee
Description
A vee bottom with a double concave that increases in depth toward the tail
Effect
Creates a pivot point and lift
The spiral vee was introduced in the 1970s as a refinement to the vee bottom. It was designed to create more bite by moving the peak of the bisection closer to the fin and hollowing out the panels toward the rail.
Other surfboard bottom contours include:
Reverse vee: A vee that peaks between the entry rocker and the leading edge of the front fin, and fades to flat in the tail
Rolled vee: A vee bottom with some belly curve added to the panels
Concave: A complicated and debated design feature that is commonly used on modern surfboard bottoms
