Could any one tell me the advantages and disadvantages of a flat bottom contour. My board seems to be super flat. No concave or vee. I.E. wave catching ability. Thanks.
It’s gonna depend on other factors too. Rocker, rails, outline, foil, fins, etc. In general, my understanding is that flatter is generally faster. There is less to disturb the board planing on the water than with various contours that get used for specific purposes - belly, vee, concaves. But you cannot get away from the other aspects of the board. Low rocker & flat bottom could mean fast and stiff. Lot’sa rocker & flat could mean slow and squirrly. More details and I bet you’ll get you more opinions. Eric J
i dont think bottom contours (V or concave) have much to do with the wave catching ability, except sometimes with a nose concave, offshore wind seems to really push you back out of the wave (but thats mostly with a longboard). Volume and entry rocker are the biggest factors for paddle speed into a wave. Flat is nuetral for riding characteristics. Nothing wrong with a flat bottom!
All other things being equal and simplistic: a flat bottom will catch waves easier than a displacement hull. A concave bottom pick up waves even better than a flat bottom. Flat bottoms belong to the abcs of shaping. Perhaps a starting point, and maybe for an ending- but more often theyre simply the shaper`s equivalent of training wheels. If you doubt that statement, try shaping a properly designed displacement hull or an edge board. Good luck!
The board I shaped is 7’10", 15.5, 24, 16. Kind of weird dimensions, but I thought I would try to mix things up from my other boards. Rocker= 6" tail, 3.5" nose. Foil is centered towards nose, flat bottom contour and hard rails from tail to 16" in and then the rails are rounded in. My first shape.
I worked for a few years in a surf shop and almost every Rusty that passed through had full length flat bottoms (I checked with a straightedge). I’ve also ridden Lopez, Mike Estrada, JC, and Pesce boards with flat bottoms that were great, personal favorites. It just doesn’t seem to be very cool for most shaper’s to admit that flat bottoms work. Remember what Greg Loehr said awhile back that what works well for you may not work for anyone else.
I am a proponent of falt bottoms with a subtle vee starting from about 6 inches from the front fins (we are talking tri-fins). I agree that super flat bottoms due work but I don’t think the are the training wheels for a shaper, it is simply a bottom design which happens to be easy to shape. Though flat bottoms due tend to be faster because of the amount of bottom planing surface area and the water release create buy such amounts of water exiting the tail area, the wave catching ability is not soley dictated by it’s planing surface area. A board’s ability to catch waves is largely affected by the volume of the area on the board where the sternum of the surfer is situated, give or take a few inches. And more importantly, wave catching ability is affected greatly by the amount of “tail” rocker. However, one should not always sacrafice other import board riding design features for a boards wave catching abilities. Most of us designers are always trying to balance a board’s design parts to create a complete “magic board”. I have found that an all around california wave catching board has a nose rocker of about 5-5 1/4" and a tail rocker of about 2 1/4". You can certainly find a Clark blank to meet that need. However, the closetolerance blanks generally do not come with sufficient volume under the sternum area. I would try and not even touch that area until the rest of the blank is skinned. It is possible to zero the planer blade or drum when skinning over this crucial wave catching area.
RI - sounds like an interesting shape. I’m assuming that the rocker measurements are flopped and should be 3.5 in the tail and 6 in the nose. I’d say, a flat bottom on a board that wide, if the entry is smooth, it should skate well and pickup waves easily. how about the Fins? Tail shape? FYI - a local LI shaper (Pistol Pete) advised me for my first board, ‘keep it simple and use a flat bottom & deck’. I did this on my first board, a 6’6" twin/fish and it works well. That board also has about a 16" tail and is just over 22" wide, & 3" thick under the chest. Post the board, maybe? Best, Eric J
Eric, Thanks for the info. The board has a square tail and I"m using a single fin (cutaway.) I plan on posting a pic once everything is completed. Just have to sand the hot coat down now.