What are the advantages and drawbacks of shaping concaves into the deck of a board? I’ve seen a few different approaches, one was a 3/4 length concave running up from the tail. The other had a footwell under the back foot, above the fins. I’m guessing that weight reduction, flex and control could be some of the advantages. Do deck concaves significantly reduce the strength of your blank?
What are the advantages and drawbacks of shaping concaves into the deck of > a board? I’ve seen a few different approaches, one was a 3/4 length > concave running up from the tail. The other had a footwell under the back > foot, above the fins.>>> I’m guessing that weight reduction, flex and control could be some of the > advantages. Do deck concaves significantly reduce the strength of your > blank? >>>>> Been working with concave decks for about the last 4 years. Inspiration came from the G&S Waterskate, I call them the Mutant. Theory is by moving thickness away from the center and out to the rail line you create a lower center of gravity which gives you much greater sensitivity. Other benefits are better control due to more contact between deckline and your feet.Drawbacks are minimal if you use the correct blank and actual strength can be increased by having more volume out on the rail line. I have used concave decks on eggs, performance style shortboards and Joel Tudor, Todd Morcom, and others are riding them in Hawaii this season. Check out Rob Machado in Shelter, 5’8" Mutant Moon single fin. sk
sk, What’s the depth and shape of your concaves? How has the feedback been on your boards? I can imagine it would take a little getting used to. I keep thinking skateboard decks.
sk, What’s the depth and shape of your concaves? How has the feedback been > on your boards? I can imagine it would take a little getting used to. I > keep thinking skateboard decks. The depth is determimed by factors such as surfers ability(Better surfer, generally a deeper 1/4"+ concave) and you get used to them in a hurry.As far as the comparison to skateboard decks I think you can see the similarity between the two. The shape of the concave is about 3/4 to 7/8 of the deck length. sk
i’ve long wondered why surfboards don’t have concave decks. in theory it makes total sense.(imagine riding a convex skateboard…) i haven’t tried one yet, i’ve just kind’ve assumed it would kill the board strength, but i’m considering trying it out. i know doc lausch does some concave decks on his y2rsq boards. my guess is that concave boards have to be pretty thin(< 2 1/4") with boxy type rails. i’m thinking of a performance style shortboard. sk what are your rails like on your concave shortboards?
i’ve long wondered why surfboards don’t have concave decks. in theory it > makes total sense.(imagine riding a convex skateboard…) i haven’t tried > one yet, i’ve just kind’ve assumed it would kill the board strength, but > i’m considering trying it out. i know doc lausch does some concave decks > on his y2rsq boards. my guess is that concave boards have to be pretty > thin( style shortboard. sk what are your rails like on your concave shortboards? The rail shape on performance style shortboards is much fuller (boxy) , however the apex of the rail as it turns into the bottom edge is lower to compensate for the volume of foam being transfered to rail line(Brewer down rail).These boards are Quite different to the one’s Doc is making, his being very subtle concaves and soft , very square boxy rails. sk
i’ve long wondered why surfboards don’t have concave decks. in theory it > makes total sense.(imagine riding a convex skateboard…) i haven’t tried > one yet, i’ve just kind’ve assumed it would kill the board strength, but > i’m considering trying it out. i know doc lausch does some concave decks > on his y2rsq boards. my guess is that concave boards have to be pretty > thin( style shortboard. sk what are your rails like on your concave shortboards? The main reason why they haven’t taken off in the past is …simply put…they are more work for the builder…I have built many ,mostly for my self.They ride great!!!Herb.
my big concern is the board feeling too corky in the water. my last flat deck/boxy rail board was just too much volume. seems spreading the foam out to the rails has a huge effect on volume/displacement. do you guys go thinner on these boards overall to avoid that corky feel?
my big concern is the board feeling too corky in the water. my last flat > deck/boxy rail board was just too much volume. seems spreading the foam > out to the rails has a huge effect on volume/displacement. do you guys go > thinner on these boards overall to avoid that corky feel? Concaved deck tend to place the float out to the rails,(rather than a convexed deck which carries it’s float mainly in the center) giving you a corky feel.Just remember to ajust the flow at the rail to reduce this.Herb.
Use extra glass as a deck patch?.. Clark Foam clearly addresses the “overshaping” issue in their blanks. It would seem that cutting a concave deck would expose the softer core foam.
Use extra glass as a deck patch?.. Clark Foam clearly addresses the > “overshaping” issue in their blanks. It would seem that cutting > a concave deck would expose the softer core foam. Aside from today
s potential production/labor problems in building them, concave decks have been around for a very long time (clearly seen on some of the ancient Hawaiian surfboards), and are completely functional... and while not for everyone, I personally have made and used a wide variety of concave/conforming decks for 25+ years. They generally feel more ergometrically responsive, i.e., tending to better accommodate the curves of the human body when paddling and riding. Designed properly, they can offer significantly improved handling, balance and sensitivity characteristics over crowned and flat decks. As with many other items in the world around us that we repeatedly come into contract with for extended periods of time, the closer we approach harmony with the function, weight, and shape of our own bodies, the more we can anticipate the freedom of naturally enhanced performance. There is a vast difference between having to adapt ourselves to a surfboard, and simply building that particular fixed shape to accomodate us... Taking that line of thought farther, theres an even greater contrast between a surfcraft that not only independently adapts to the contours of one`s own body, but also the ever-changing curves and textures of a wave, as is the case with modern, inflatable surfmats. A historical footnote: George Greenough long ago recognized the advantages of concave/conforming decks, and has been successfully utilizing them in his high performance surfcraft for over 40 years.
Aside from today
s potential production/labor problems in building them, > concave decks have been around for a very long time (clearly seen on some > of the ancient Hawaiian surfboards), and are completely functional... and > while not for everyone, I personally have made and used a wide variety of > concave/conforming decks for 25+ years.>>> They generally feel more ergometrically responsive, i.e., tending to > better accommodate the curves of the human body when paddling and riding. > Designed properly, they can offer significantly improved handling, balance > and sensitivity characteristics over crowned and flat decks.>>> As with many other items in the world around us that we repeatedly come > into contract with for extended periods of time, the closer we approach > harmony with the function, weight, and shape of our own bodies, the more > we can anticipate the freedom of naturally enhanced performance.>>> There is a vast difference between having to adapt ourselves to a > surfboard, and simply building that particular fixed shape to accomodate > us... Taking that line of thought farther, theres an even greater > contrast between a surfcraft that not only independently adapts to the > contours of one`s own body, but also the ever-changing curves and textures > of a wave, as is the case with modern, inflatable surfmats.>>> A historical footnote: George Greenough long ago recognized the advantages > of concave/conforming decks, and has been successfully utilizing them in > his high performance surfcraft for over 40 years. This is an interesting design disscussion, I to remember the G&S waterskates. I am having a hard time visualizing the proper rail shape. Would it be possible for someone to draw a cross section, scan it and post it?
watched “Shelter” again today and theres a great shot of rob machado with a little sk single and the concave in the deck is totally visible. how weak does this make the deck? thats still my only big concern, otherwise, the more i think about it the more amazed i am that this is not a more accepted design feature on boards today…
watched “Shelter” again today and theres a great shot of rob > machado with a little sk single and the concave in the deck is totally > visible. how weak does this make the deck? thats still my only big > concern, otherwise, the more i think about it the more amazed i am that > this is not a more accepted design feature on boards today… Wouldn’t an a board made with EPS foam work good on these? The EPS wouldn’t lose any strength from the deck being scooped out and would provide better floatation than a polyu blank. Seems like the answer for what you are worried about to me.
watched “Shelter” again today and theres a great shot of rob > machado with a little sk single and the concave in the deck is totally > visible. how weak does this make the deck? thats still my only big > concern, otherwise, the more i think about it the more amazed i am that > this is not a more accepted design feature on boards today… There is also a small blurb on surfline how Todd Morcom was stand out surfer of the day test shredding a sk concave deck single fin at small Ehukai.
Use extra glass as a deck patch?.. Clark Foam clearly addresses the > “overshaping” issue in their blanks. It would seem that cutting > a concave deck would expose the softer core foam. I built and am currently riding a concave deck. Board was shaped like normal with minimal foam taken off the deck.scooped out the tail area to add flex and concaves under front foot area leaving a 3 inch wide arch bar in the middle. Concaves do not extend to the rail but stop on the crown.This way the board mantains all of the original shape. board rides great and the bigger the surf the faster it goes. The flex comes into play with the increase of wave power.board is a six two. Scooped out tail ends at middle of the fins to lessen the chance of breakage. downside -two much flex caused glass to buckle at the flex point the single 4 deck was too light and scoop was too severe. Probably only needs to be half an inch deep Both the scooped out tail and the double concaved deck with arch bar lock your feet in no slipping. Glassing needs to be tight and sander needs to be cautious not over sand. Mine wieghed in at 5 lbs.just go for it
Wayne, Have you been sleeping in the laminating room again? I told you before laminators don’t need to sleep with the resin, SK
Wouldn’t an a board made with EPS foam work good on these? The EPS > wouldn’t lose any strength from the deck being scooped out and would > provide better floatation than a polyu blank. Seems like the answer for > what you are worried about to me.>>>>>>>> I have not had any problems other than some minor denting on decks using mostly Supergreen and Superblue Clark Foam blanks. EPS foam gives you a different feel which does not give me the riding characteristics that I am able to have with Clark Foam. In addition EPS is a pain to work with . For most of you that enjoy shaping your own boards it is still better to use polyurathane foam, it continues to be reasonable cheap ($) and available. Don’t worry about a few dents, unless you opt for Using Ultralite blanks a good glass job will be all you need. sk
SK I only fell asleep a few times At leastI only remember a few times See you at christmas and waves were overhead tonight and I wore trunks
watched “Shelter” again today and theres a great shot of rob > machado with a little sk single and the concave in the deck is totally > visible. how weak does this make the deck? thats still my only big > concern, otherwise, the more i think about it the more amazed i am that > this is not a more accepted design feature on boards today… All other details being similar, utilizing the compound curves of a conventional, crowned deck, or those of a concave one, are generally much stronger than a straighter, flat surface. What
s truly amazing is not that concave decks arent widely accepted, or that theyre not easily found in typical surf shop showrooms, but rather that more home builders dont take full advantage of their nearly limitless creative freedom to exploit such design concepts in spite of popular trends. Once upon a time, more than a few garage shapers/builders took hold of that powerful sword of freedom and became a myriad of bright, shining lights pointing the way to surfing`s new tommorow… someday, it will all happen again.