Hi. Could somebody explain the main difference (when surfing). Let’s say a Christenson fish that has a single (not runnunt to the rail) and a DVS Hydro hull where the concave is more a inverted V. The panels (rail) are not flat so it’s even more difficult to compare. So, could we compare (ceteris paribus) the type of concave and the the use of the panel. How would the Christenson fisf surf with the oustside panel (hydrohull style)? And the same christenson fish with only the inverted V Concave?
I lost you somewhere in the panels and I’m not big on model names/specs, so I don’t visualize what you are describing.
Intuitively, I’d suggest that a sharp(er) peak in a concave would act more like a channel.
But here’s some reading that may help. Terry Hendricks was so far ahead in his thinking.
http://www.rodndtube.com/surf/info/Hydrodynamics.shtml
Stewart’s Hydro Hulls combined Concave and a Chined Rail. Fantastic combination. Fastest most responsive 9 ft’er I was ever on.
The conventional wisdom is that concaves are for narrow widths (like those 14.5" tails in the HPLBs and HPSBs) where they can add drive. Wide widths already have ample surface area so they don’t need additional lift and drive; they need control so that’s where convex comes in. Traditional longboards employ belly - that’s for control. Narrower shapes can do similar with smaller amounts of convex.
The panels (and belly) at the rail are there to smooth out the turns, otherwise the transitions are too abrupt for the wider widths. The OG fish designs included a 3-4" x 1/8th panel at the rail. The comparatively sharper edges on the Hydrohull and Stewart boards is there for release - to liven up the transition.
DVS - Dick Van Straalen Hydro Hull. Same name for a completely different design than the Stewart Hydro Hull.
https://www.swellnet.com/news/talking-heads/2019/01/29/audience-dick-van-straalen
Great interview , loved the line " and people think 1/8 of an inch is gonna make a difference "
One veteran shaper from HI who does channels says that the optimum for a regular tail width is 6 channels. And a sharp edge at the rail
Hi,
I wrote the Cristenson fish as an exemple because it looks clear that it has a narrow concave (in a wise board). Opposite concept to a shortboard with a concave rail to rail. But I guess that the flat panel onthe rails feels different than the convex panel on the pic. I like full concaves on boards undet 19 3/4. I like deep cond in fishe but the ones I surf got deed doubles on the back. A lot of people likes christensons fishes (single conc) but I’ve never surfed a suxh a wide board with single conc under the back foot