Flat bottom vs double concave hulls

ittiandro · Joined: 22 Nov 2009 Posts: 294

I do mostly subplaning ( both by choice and necessity, given the prevailing conditions here) and the Bic 293 Core I have is a very poor performer in sub-planing. Currently I am looking at the Exocet Wind SUP 11”8” and the 11”6 Bic ACE TEC Windsup. I could get the Bic Windsup for about $ 300 less than the Exocet. What worries me, though, is that the Bic Wind SUP still has the same( just longer) flat bottom of her “ planing” sister Bic293 Core I want to get away from, and I wouldn’t want to trade a one dollar bill for ..four quarters. The Exocet, on the other hand has a double concave hull, which should ensure a better gliding in sub-planing.
I weigh 85 kg, I don’t do wave sailing, mostly flat water or small waves, speed or planing are not my priorities, but stability is, especially when gybing and tacking.
I wonder if there is really a substantial difference on account of the hull design between the Bic Wind Sup and the Exocet Wind Sup. Definitely, if I compare my 293 cm flat bottomed Bic 293 with the double concave hull of the old 12 ‘ Mistral Competition I tried, there is a HUGE difference in subplaning.But perhaps the 12’ length of the Bic Wind SUP makes up for it.
Can you or anybody comment on this?

Thanks

whitevan01 · Joined: 29 Jun 2007 Posts: 607

here we go again. I am sure others will chime in here with a lot of stuff, but here are some basic facts:

the longer narrower lower drag hull of the mistral gives it better glide characteristics than the shorter wider higher drag hull of the Techno, not so much the bottom shape.

the concaves in the bottom are really to promote earlier planing. as the water rushes underneath the board, the concave shape helps to provide lift (run water over the concave portion of a spoon to feel this effect.)

another benefit to the concaves is that they help the board to cut through chop.

just the bare bones of this discussion. let the games begin!

ittiandro · Joined: 22 Nov 2009 Posts: 294

LeeD · Joined: 12 Jun 2008 Posts: 1175

Sub planing, more surface area underwater allow for higher sideslipping resistance, so it would end up faster, the double concave.
How much faster? About the difference of 6" in hull length, or negligible.
Sub Planing, a D-2 board like a Lechner or a Crit would blow doors on either the boards you mentioned, but it's round bottom AND 12+ in length.

NOVAAN · Joined: 28 Sep 1994 Posts: 1549

In the conditions you are talking about, The bottom shape of a board will make about zero difference. Rocker line will make a very small difference.
Weight makes very little difference. Except carrying and loading. Durability however makes a big difference. Bic makes great boards. I have sailed just about every offering since the early eighties. It a shame they don't still offer a high performance line of boards. The Bic E-Rock and Astro Rock are legendary. If your a beginner or sail in a rocky beach area, The Bic is the way to go. You can beat them up and they will last for years. If you search this form for Exocet, you will find there have been many problems with this line of boards. Their 11'6 windsup has way to many issues with cracks and delamination's. The dagger board area and rails are highly suspect. I have had my share of issues with this line of boards and would be hard pressed to recommend one. Buck for buck, go for the Bic.

swchandler · Joined: 08 Nov 1993 Posts: 10588

Two things that are important to consider when contrasting different products are construction and weight. One product might be very durable, but it may also be a bit less lively and slower to get up to speed. A lighter less durable board might offer the greatest potential for speed and maneuverability, but you have to be very careful about handling and damage. With every upside, there is usually a downside that goes with it.

Do you want a board that acts more like a shortboard once up to speed and planing? The Exocet has the step tail which reduces overall length once up on a plane, and it will tend to initiate jibes more like a shortboard. It's not like the Bic doesn't perform and that it would be hindered by its extra weight and different bottom shape, as it just may offer the smoothest most comfortable ride.

Overall, you need to review your goals and follow the best path.

boardsurfr · Joined: 23 Aug 2001 Posts: 1266

beaglebuddy · Joined: 10 Feb 2012 Posts: 1120

If you are primarily sub planing as you stated then neither board would be the correct type of board to buy because they have planing hulls. They work OK sub planing because they are very long not because of the hull shape.
You need either a board with a displacement hull or at least a similar length board that is much narrower.

ittiandro · Joined: 22 Nov 2009 Posts: 294

Wind-NC.com · Posted: Sat Aug 29, 2015 5:36 pm Post subject:

Starboard makes the Freeride 12'2" x 30", which might be another really nice option for you. You can get an epoxy or inflatable one. Displacement nose, but a flatter bottom and thick square rails for the rear 2/3. Glide and tracking of a race board, stability of a flat bottom all around board, so it's kind of a blend between an old D2 and a board like the bic or exocet.

http://star-board-sup.com/2015/products/freeride-12-2x30/