sorry Bill, the tone of my opening line came across a bit strong, I was just very surprised that you thought the tail rocker was thought to be high when I think it is on the low side. the rest was just me enjoying explaining the rationale behind the rocker. I agree that on the surface the nose rocker sounds high but the nose tip measurement alone doesn’t tell the full story thats why my post ended up so long. Please post your numbers here, I’m interested and I promise I won’t react strongly! as always opinions vary on these things.
Well, the first question I have is ''Where will this 'gun' be ridden?'' The intended type of waves, influence the design, and fin selection. At least it influences me. Also the skill level, and weight of the rider, are important to know. I'll help you, if I can, but I need a little more information.
G’day Ken, I have posted specs for my Josh Dowling 6’ 10" stepup. Included are widths, thickness, rocker and fin positions. Although this was a custom for me and I chose some of the dimension I did get Josh to comment/adjust and he said those measurements are “very sensible” and he has built other customs from the outline and rocker (although he slightly tweaks the tail rocker I think). The double to single concave works well in a heavily textured wave surface.
Here’s a very basic start. My Patagonia Tom Curren is 7’2" x 18 3/4 x 2 5/8. Don’t have the other dimensions. It’s big for me for me in beach break storm surf. Width and thickness are fine but I don’t need all of that length. Sounds like a 6’8"-6’10" would work fine for him.
I don’t know, Josh chose the wide point (and the nose width). I do remember him telling me that it is more forward than his shortie measurements, but that doesn’t necessarily mean forward of mid-pt. Its down the coast and I’ll measure it on the weekend and post here.
I am very happy with the way this board works and I post these measurements with confidence, Josh knows his stuff when it comes to step-ups and guns. The weather isn’t very good here but we do get decent waves.
for the sake of this discussion lets assume that your mate wants it for the same application as me: tall waves carrying a lot of water, steep at the top but with a sloping base. No rhino chasing and no square tubed belching slabs - I don’t do that stuff. At my skill levels in step-up conditions going fast in a straight line is important! - however this is a semi-performance shape if your mate is up to it. Josh does more than one rocker type for that length, but the specs for this one is my choice and I like them.
If thats the situation then I think exactly those specs would work just fine for 73kg +. I’m a little 55kg but I always ride very normal oversize boards and I can duckdive this board so your mate could easily do that. However as a reference pro Pancho Sullivan has a 6’ 10" stepup model by Bushman (comparable outline dimensions) which is 2 1/2 thick. So if Alain’s T Curren gun is 2 5/8 it looks like you can go thicker if you want to - IMHO a good idea.
What have I got, you ask? The answer, of course. Are you ready for it? Have you settled on your dimensions yet? If 6' 10'' is the length, then nose rocker should be no less than xxxxx inches, and no more than xxxxx inches. The tail rocker should not exceed xxxxx inches, or be less than xxxxx inches, with xxxxx inches being the ideal for a 6' 10'' board of ''gun design.'' WP? Have you decided yet? For the subject board, use 45% of the length, measured from the nose.
ps: Fin selection, and position, can make or break a boards performance capabilities. Are you making a 1, 2, 3, or 4 fin setup?
Bill, no way is 2.3" excessive tail rocker. Those measurements are what I measured with the rocker stick, however I do have all the original measurements that this rocker was designed from. My original design measurements has the tail at 2.36 ie within 1.5mm of what I measured - thats close and I happen to know that Josh’s production methods produce an accurate match.
What Josh did was use my template unmodified thru the main sections of the board, but added extra flip in the last section of the nose - the bit that isn’t in the water when riding normally. Looking at my measurements below the 2’ from the nose section isn’t high. So the whole rocker measurements need to be put into context. Another thing to consider is the nose width measurement, narrowish but not too narrow and I know from experience this board handles brisk offshores well without lifting.
To get 6’ 10" from say US blanks the 6’ 10" or 7’ will be needed however an interesting comparison of rocker to get an idea of whether something is high or low comes from the EA 6’ 9" which I have put in brackets below because this has a bottom length close to mine. Also in brackets for comparison are the Rawson (an old blank I think) and the extinct Clark Hybrid (from which I have had a custom board made some years ago). The Rawson is too old a design but you can see that my stepup isn’t that far off the EA and the Hybrid at various intervals, so there really is absolutely nothing radical going on. My stepup was designed to handle exactly the conditions I described earlier in this thread. If you want to Ken you could easily add 1/2" of tail rocker to mine and get a good board provided the front section is modified in a complementary manner. The rocker can be your choice, and maybe someone else will offer some hard numbers or you can just use your judgement. However the one I’ve given is for what its worth tested by me and deemed to be good for what I wanted it for!
Mike Daniel has cautioned me about using blank rockers as a guide to a board rocker, however I’ve done a reasonable amount of this sort of comparisons on my own and friends boards and just for the purpose of comparison and spotting rocker trends it is a useful tool. Anyway my stepup rocker wasn’t designed from a blank rocker it was based on the 6’ 6" Flyer 2 scaled up, tweaked a little and with a bit of extra nose flip at the end.
However I really don’t have much idea of how to choose a blank to match, I gave Josh the template and he produced it from EPS. For PU it seems its not as simple as choosing bottom rocker that matches and that its more a case of getting the deck to match the foil for deck strength reasons. My board is foiled out - it has to be for my size, Josh did rather well to get me duckdiving on that length and took away unecessary foam. I don’t have calipers so can’t get you foil measurements but I’m sure you can use your judgement.
So for blank choosing this is where we need professional help!
I’ll be heading the opposite direction down the coast this weekend so won’t get to measure the mid-point until tuesday.
starting from 1’ from nose the Josh Dowling stepup measurments on the left:
1’ - 50 mm (EA 49) (Rawson 51) (Hybrid 48 mm)
1’ 6" - 26 mm (EA 28) (Rawson 30) (Hybrid ??)
2’ - 13 mm (EA 14) (Rawson 16) (Hybrid 13 mm)
-------Rear------
1’ 6" - 18 mm (EA 20) (Rawson 19)
1’ - 28 mm (EA 31) (Rawson 26) ( Hybrid 25)
T - 60 mm (EA 64) (Rawson 51) ( Hybrid 57)
What have I got, you ask? The answer, of course. Are you ready for it? Have you settled on your dimensions yet? If 6' 10'' is the length, then nose rocker should be no less than xxxxx inches, and no more than xxxxx inches. The tail rocker should not exceed xxxxx inches, or be less than xxxxx inches, with xxxxx inches being the ideal for a 6' 10'' board of ''gun design.'' WP? Have you decided yet? For the subject board, use 45% of the length, measured from the nose.
ps: Fin selection, and position, can make or break a boards performance capabilities. Are you making a 1, 2, 3, or 4 fin setup?
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Bill
this would be a thruster set up
this guy is not going to cratique the dimentions ,,seeins how he's not givin me any.
if the board comes out nice looking and fast Im sure he will be happy