Ok Guys heres the story I’m 5’10 190 lbs. My board in question is 6’3 13 x 20.25 x 15 x @ 2 5/8 thick board has single concave going to a flat section off the tail, concave is at its deepest 1/4" deep. Float is not a problem. The board does not seem to perform well for me in small florida waves. It seems to be sticky and does not pick up speed very easy. I was not sure if it was the waves or me. The true test was mexico, Perfect left points. The board worked extremely well. I was actually getting in to waves and making sections that no one else was. The board drove real nice off the bottom but when i went up the face of the wave to come off the lip, the board would be really grabby and it was hard for me to dis engage the rail. Im thinking i might have to much rail volume?, what going on, What should i do? Go with a more pulled rail and thin out my board to maybee 2.5 thick. Or would i still be better off with the thickness i have and thicker rail. I have posted pics of my board below so you can have an idea of my rails and board shape. If you have any suggestions as far as rail or even a bottom concave that would work better for a heavier guy that would be great! Hope i didn’t ask to many questions for one post.
And heres some more pics
Hey Josh,
I test a lot of boards. Some time back, I experienced exactly what you have described.
Although some may refute the following, here is what I found:
The sticky feeling is most likely a problem with the exiting portion of your bottom contour
and the amount of rail tuck going into the hard tail edge. Without completely spilling the
beans and polluting your mind with one way of doing things, your board might possibly
have too much edge/not enough tuck just ahead of the front fins, and the concave may
be continuing too far back toward your flat tail transition for its given rocker.
Is it possible to get a photo of the rail tuck contour ahead of the fins (use side-lighting)?
Where is the 1/4 inch contour maximum? (distance up from tail)
How deep is it between the front fins?
How deep is it at the rear fin?
The board might have a bump in the rocker where it hits water when in slow waves, but
in good waves the water entry point shifts back and the board gets freed up. So check
the rocker/contour in the water entry area; the area where water first touches the board
while surfing in small waves.
What kind of fins are you using? What template?
Thanks for your reply I the rocker the nose i believe is 4.5 and the tail is at 2’’ or 2 1/4 as far as the single concave goes it runs pretty much from the nose to the tail it is at the deepest in the middle of the board at 3/16" and that stays consistant through to the tail to the front fins then once past the front fins it starts to fade out to 1/8" behind the rear fin. The fins im using are the fcs PC-5 and they are set at 6 degree’s also my hard rail starts at around 15 inches up from the tail then the bottom of the rail is a standard 30 degree angle then then disected to another thirty" fred tool". I was thinking about changing my bottom concave to a triple concave and thin out my rail volume. Do you think this will help my problem or cause more. Ive definently got the board outline dialed in i just got to get the rest set.-thanks for your help _josh
It could be a number of things. Maybe just figuring out where all the buttons are? You say the board is dialed in so…
PlusOneShaper had some good input on possibilities with the rails and concave.
The speed you describe in bigger waves may also be a combination of the relatively wide tail outline and flattish tail rocker combined with concave through the tail. Those same factors can cause a board to feel grabby, sticky or tracky.
You say the tail rocker is between 2" and 2 1/4"… in short boards, even slight rocker tweaks can make a big difference. If you can, get an accurate measurement on your tail rocker and make accurate changes, increasing your tail rocker by 3/16" - 3/8" might help you out. The ride difference between 2" and 2 1/4" could be substantial so try to get a good measure on that before making changes.
Play with fins! A smaller/more upright trailer and/or change in fin positions can make a big difference. Generally speaking, moving the trailer fin forward will make the board looser so you could trim the front of the tabs a little and get slight forward adjustability. Probably no more than 1/8" - 3/16". The side fins will absorb any impact if you hit something but modify stock fins at your own risk.
Some fin systems allow adjustments. You might check into something like Red-X or ProBoxHawaii. Red-X allows 3/4" fore aft adjustment. PBH allows up to 1/2" fore and aft and has inserts for 0, 4, 6 and 8 degree cant. Both systems have received good reviews here on Swaylocks. There are other systems as well.
slow in weak surf, perfect in powerful surf…I’d suspect too much toe-in on the rail fins…
I just got an accurate reading on my nose and tail rocker and i was way off. The nose rocker is actually 5.5 and the tail rocker is 1.75. Oh when i said the board was dialed in I only ment the outline shape, it just fits me real well for my size the outline is real cresent shape-everything else is up for possible change.
Yikes! for a board that length I would be running more tail rocker as per John’s suggestion.
2-3/8 to 2-1/2 is not out of the question.
1/16" of rocker change in the last couple of inches of the tail will make a feelable difference.
Mind Johns words. Keith is also right, so what is your toe-in? (lay a long straight edge on the
flat side of the fin and describe where it projects, that is: to the nose, 2 inches off the nose,
etc).
The bottom contour you describe (IMO) runs for too long. You might disagree but there is
a benefit to having zero concave by the time you reach the rear fin. The max point is too
far forward as well. Good that you ran it almost constant through the board but you might
be stoked if you put the max point just ahead of the front fins, like 20 inches up from the
tail. Single con works great on round tails but a slight double added to the single will give
more drive.
Your edges sound about right, I was going to say break it at 16" but even at this point the
edge should be about 1/8 to 1/4 in from the apex of the rail. Rail should start to look real
round as well, like a ping-pong ball.
Disclaimer- the above design elements apply to the specific board in the photos. There are
many other ways to skin a cat, and there are a lot of different kinds of cats out there…
You didn’t say how you took your rocker measurements but I’d agree with
PlusOneShaper that your tail rocker is pretty flat. Fast but tracky. Good for down the line “racetrack” waves but maybe hard to cutback.
Dave Parmenter’s somewhat dated (but still valid) “Anatomy of a Surfboard” lists standard thruster tail rocker at 2.375" but I’ve seen shortboard tail rocker even steeper, especially with a lot of concave.
The rocker in your board is a done deal so that leaves your fins for adjustment on the current board.
Even something simple like shaving 1/8" - 3/16" from the front of your fin tabs might allow you to move your trailing fin forward a little.
Maybe coupled with mid sized H-2s as sidebites?
Somebody like Halcyon might have ideas on a smaller area vertically oriented custom design for that trailing fin.
I took my rocker measurements with a long metal straight edge balanced on the bottom of the board running from nose to tail and i measured from the end of the tail up and from the nose up. So with me staying with the outline shape of the board and staying with the 6’3 in size- should i just change my tail rocker to 2 3/8 and change my bottom concave to a triple concave. Do my rails need to be thinned out or should i just leave them just like they are like i said my rails are full and my board thickness is 2 5/8 . I didn’t know if making the changes to the tail rocker and bottom concave would fix my problem with the board picking up speed in florida waves, but on the otherhand i want to try to eliminate the rails from being sticky when i turn off the lip of the wave when the waves get better. I’m at the firestation today so i will check the toe in on my fins tomorrow, but if i recall they were pretty standard like 2’’ off the stringer by the nose.-thanks josh
you should be able to use rails as large as you like so long as they have some form of taper (read that
minimum vertical band) either with tuck into the bottom, or transition into the deck. You could even
have a flat deck for more float just be sure to do the taper.
In the last 3rd of the board the presented vertical area starts to increase then from about 16" to the
tail tip it might be a good idea to have a fairly vert bit of rail to shed water and add rigidity. Radius for
the tucked rail should be moderate, like 1/2" max to the tucked edge occurring at the widepoint…
so the actuall full rail is not what is causing my problem? I have been told that full rails are usually good for heavier surfers because they tend to drive off their rails? But on the downside i was told they can be sticky and harder to turn.-josh
I took my rocker measurements with a long metal straight edge balanced on the bottom of the board running from nose to tail and i measured from the end of the tail up and from the nose up.
LeeV convinced me that this is the best way to measure rocker if you don’t have one of those rocker stick thingies…
Measure your board and mark midpoint on the bottom. Place center of straight edge so it balances directly at midpoint. This should give you a pretty consistent reference for measuring various points along the curve. 2 3/8" tail rocker should be easier to turn than 1 3/4."
I also like PlusOneShaper’s idea of fading out the concave behind fins. Sounds less tracky.
Hi JMJ,
You say the rails are sticky, maybe they are not !! What makes you think it’s the rails?
Wouter
I merely guessing that the rails are my problem, i relize that it could be my tail rocker though. So what do you think as far as my options go. I don’t want to go to drastic where i have to learn to surf the board over again. I was thinking about keeping my rails the same changing my tail rocker to 2.5 and putting a triple concave bottom-josh
Well, you’re right the rails are digging but it is due to a couple of other things, like rocker, bottom shape, etc.
In your case concave actually allows the board to ride lower in the water and when you push the board on rail
the concave gives you back a grab or bite feel. It is important to allow that ‘grab’ to let go in parts of your board.
As a firefighter you know how important it is for a hook-and-ladder rig to have the rear end kick out in turns. That
is what’s needed for your board when snapping off the top. You almost the nose to swap with the tail. Well, the
quicker you make this transition from max con to flat, the more you will have this effect (yes, you can have too much).
Basically, for that kind of board you will want to bunch up the water ahead of the fins and pass it through the front fins, then immediately releasing it just after that, venting it with the least resistance, outwards off the sharp tail rail edges, but not too much causing a (lower pressure) vacuum at the tail block.
The rail shape through the main part of the board is important, as it will dictate your approach into a turn, and the extent of the bite while up on rail. Too fat and the rail won’t penetrate, too skinny and the rail will bite too much. A lifty tail rocker (read less t.r.) will drive the nose down (like the trim tabs on a speed boat) making it seem like your rails are catching but they are just countering the tail lifting.
So, with concave all the way off the tail (your particular board) you run the chance of scooping the water a bit, as the water wants to exit to low pressure (ie. water will fan out just behind the front fins to the nearest edge). This “trim tab” caused by the concave in the tail is interfering with the easiest flow, giving a “nose down” pitch. It is subtle and it may not make intuitive sense right away… This “bogging” is accentuated while on rail trying to turn during bursts of speed/energy. If there is too much of this “down trim” the amount of energy diverting flow that wanted to go cleanly off the tail “competes” with your forward momentum.
Lastly, the flow is not one-dimensional; it does not just go nose-to-tail. It fans in, accelerates, and fans out. When you look at your tail concave (and re-read this stuff) you might start to see the part of the concave that might hinder the release of the water fanning out off the tail. Yes, water that is fanning out has a lateral component which can also produce drag through turbulence (maybe another thread)…
Don’t know if that made sense… …just make a killer board, you will be happy.