I looked in the archives (breifly)
So let me ask this,
what is your thoughts on single concave through the entire length of a board?
The board in question is a freshly shaped (not glassed) 6’ 2" quad fish
I have about 3/16" concave in the forward and mid belly dropping to about 3/32" through the fin and tail
I realy like the way it looks and Im sure this will be a fast fish
but…
will it still corner?
your input please…
That’s all I use personally.
I go about 1/8" thru a 1/4".
Starting just forward of the low point of the rocker to the Leading edge of the out board fins.
Herb
but does it continue through the fins and out the tail?
Single concave all the way through is all for the lift in the tail. It goes faster because it sinks less. I like it for a small wave trick board in slow waves, where my main concern is keeping up speed. You can make the board carve by pure overpowering the tail lift. This is what you would usually want in a small wave quad fish - yea, it will go fast and it’ll rip!
Here’s another thought. Once the wave gets enough power to where the wave does the work for me, I love a single concave that completely ends in front of the fins. Where does the moving water go when the concave ends? It is released from under the board, giving me less resistance to my movements.
Take a look at the picture
I like the maximum concave under my weight, where it gives me something to push off against. When you roll the board onto its rail on a bottom turn, The moving water gets trapped in the depression and moves the board with the flow - in this case, up the face. At this point in time, I want the nose to move up the face, but not the tail. If the nose goes up and the tail stays at the bottom, I’m suddenly going vertical. In a punchier wave, I like the V to start at the fins. The speed I’m moving at gives me enough force to keep me from bogging.
I guess the concave all the way through gives speed, not by being some streamlined design with less friction, but by letting you skim higher with less board actually touching the water.
The concave ending at the fins lets me slow down just a little, sit deeper in the water, and so have more control.
I guess the last thing to mention is the direction of the water’s movement in the picture. All this happens when moving across the wave face, parallel to the shore. The concaves do next to nothing before that first turn.
so flaten her out from the fins back?
I can do that
edit: that was some good info everysurfer!
Hey Kensurf,
Not quite “flatten it out” from the fins back. What I really like for a wave with a little power - Over head but less than double- is the concave ends at the fins, goes into the v at that point, and then accelerate the rocker. I like 2 3/4" tail rocker with the last 1/4" of rocker in just the last 4". What this bottom contour does is to create a pivot point under you. You really notice the speed down the line when you drive off your front leg, and when you weight your back leg, the turn becomes really responsive, but without any slide.
Maybe I’m too old school, but the tail slide cutback just seems like a loss of all your speed and energy. I like the full speed roudhouse back to the white-water!
this board may never see much more than head hi HB surf
my usual fish quad bottom is as you say, concave to v at fins then flat at tail
I was just thinking of leaving the sutle concave through the fins and tail and wanted to know if it would still work good
yep, sounds Ideal. I’ve been surfing a 5’5" quad fish for about a month with concave at max between my feet then flat from the rear edge of my front fins back. I’m really into it, and it turns really well, it’s quickly become my standard board (i’ve not replaced my snapped shortboard). I’d leave the concave as is. You’d only be increasing the rocker by flattening the concave - slight concave vs. slight increase in rocker - much difference? (maybe that’s a thread in it’s own right)
i think i will leave it concaved through the tail
what the heck!
Ken,
I’ve found that when I get to a point where I’m not exactly sure of which way to go…that following my instincts like you plan on doing, works out for the best…not always, but more often than not.
Hey Dusty!
I needed to hear that,
Like I said before its not what I consider the normal approch
but it looks functional and fast
I got a few shots
slight concave in the tail/fin area
I will cut the swallow tail right before glassing
will cut this later
but does it continue through the fins and out the tail?
mine fades out all the way to the end of the tail, but I like what EverySurferDude wrote better.
I need to try that.
I’ve found that concaves that run out the tail have no problems turning. In fact, for me they initiate the turn earlier and maintain their speed through the turn better than singles that fade at the front fins. However, I also believe that the effectiveness of the single, particularly on thrusters, but also on quads, decreases rapidly once you get to the trailing fin(s). At that point, a bit of release behind the trailing fins, right where the tail kick accelerates, helps keep you in control in steep parts of the wave, like in the pocket or up under the lip. So I like to flatten it behind the trailing fins.
What I’d like to know, is what does a full double concave out the back do on a board with a deep swallow, like a speed dialer? I know they work, but I don’t understand the physics behind it. My guess is that maybe the deep swallow provides enough release on it’s own to compensate for the added bite and lift of the concaves.
