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Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Oct 15, 2015 3:30 pm
by nomastomas
How much rocker in your present design? With the right combination of bottom curve and fin size (small), its pretty easy to release the fins (TBG4: NR=2.75, TR=0 .75). I've done inadvertent 180s when kicking out while riding in a forward position. I suspect with a little practice a 360 is possible.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Oct 15, 2015 10:52 pm
by krusher74
nomastomas wrote:How much rocker in your present design? With the right combination of bottom curve and fin size (small), its pretty easy to release the fins (TBG4: NR=2.75, TR=0 .75). I've done inadvertent 180s when kicking out while riding in a forward position. I suspect with a little practice a 360 is possible.
Its about 3" nose 1/2" tail (more in centre with open concave)

I had tiny knubsters fins on my endeavour board as an experiment. Only about an inch deep. Surfed on them for a few months and could still 360. Then took them out one day and the board felt much faster without them (with them was like driving a car with the parking break left on a little) and 360's now spun much faster.

I don't think the benefit of fins will ever outweigh their drawbacks for me personally. :cry:

I will take this as the experiment it was and go back to my chine rail next time, it has more bite and drive. I guess it acts like a long fin? At least I now know how they both act. Hopefully I can somewhat sand off any release edge there is in the last 12" of the rail to see how much more traction that gives.

Are you still going to make your finless board Thomas?

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Fri Oct 16, 2015 12:00 am
by Pes78
Hey krusher when shaped the board did you feel the foam getting softer? I just ordered another blank in green density and lowered the tail rocker a 1/2".

Paul

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Fri Oct 16, 2015 1:02 am
by nomastomas
Keith...that project always gets moved to the back-burner. I like what Ekstrom has done with bottom and rail contours. But with El Nino just around the corner, I'm currently focused on building a p-board ("prone board" is what Buzzy Kneubuhl calls sandwich construction paipos. I like it!) that performs well in OH waves. I plan to increase the length to 50" or 52", adjusting outline and foil to maximize flat out speed. Both thickness and wide-point will be slightly forward of center. Key will be designing a board that has sufficient volume to really plane well but can still duck dive easily. Bottom will be deep single concave a la Maurice Cole's work. Just have to work out hand placement. I like the forward "bumps" of Gus Acosta's Wave Arrow, but I'm also considering a modification of the "pickle-fork" nose seen on the Gemini shapes. I think that would help to keep the elbows on the deck, away from the rail. Fins of course, either full-sized 5.25" twinnies with 1/8" toe-in and 7-deg cant, or quad with M7/AM2 fronts and a pair of AM2 center fins for rears, set using McKee's formula. I've got a couple of months to work out the details...

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Oct 22, 2015 7:43 pm
by jbw4600
Keith, If you decide to put fins on it, you might try putting some Grom sized thruster side fins. They have low surface area and are pointy. Pointy fins pivot better than the those keel like fins.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Oct 22, 2015 9:28 pm
by nomastomas
BTW, where did you place the fins? How much toe-in? Cant?

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Sat Oct 24, 2015 6:55 am
by bgreen
Patrick,

The new board sounds interesting. When will it be on view?

Bob

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Sat Oct 24, 2015 10:31 am
by nomastomas
Bob...its still in my head, but soon I should have some drawings to share

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Mon Oct 26, 2015 3:16 am
by krusher74
Pes78 wrote:Hey krusher when shaped the board did you feel the foam getting softer? I just ordered another blank in green density and lowered the tail rocker a 1/2".

Paul
The Green foam seemed to stay firm as I got deeper, but i dont have much foam/shaping experience :? , definitely firmer that a previous blue blank

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Mon Oct 26, 2015 3:21 am
by krusher74
nomastomas wrote:BTW, where did you place the fins? How much toe-in? Cant?
dont know the numbers but here is a pic, rear most position was the only place i vaguely liked

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Sun Nov 01, 2015 4:25 pm
by krusher74
Ride report update!

Well today I was looking at the board and it had a hard edge on the back 3rd of the rail and a faint hard edge as far as two 3rds up, so I got the sandpaper out and sanded all off. :?

Result hold and drive is back! totally changed the board :D

I was doing hard bottom turns and S turn cut backs with ease today, so the hard edge is only across the tail now. Interestingly 360's now spin round a little slower.

Now totally stocked with how this board surfs, 8-)

Put a cork deck pad on too.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Sun Nov 01, 2015 6:39 pm
by nomastomas
Yes, a hard edge promotes water release. Softening the rail edge, encourages water to rap around and "grip" the rail. This was the lesson learned from the 70s down-rail mini-guns. The early down-railers were fast, but prone to spin-out. The introduction of rail fins was an attempt to counter the spin-out while keeping the speed. I would think a soft edge or no edge rail would be important on a finless board. The softer-but-stickier rail you now have may explain the slower 360s. Water just doesn't break away from the rail as quickly.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Tue Nov 03, 2015 4:05 pm
by patrickSAWBOARDS
Hey Keith, The board looks amazing. Hope you have been enjoying the recent swell. Looks like we might get a bit more winter next week! Fingers crossed. See you soon.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Nov 05, 2015 3:02 am
by krusher74
Got a few waves on the board today with my buddy on his bodyplane, these are the more flat weak local waves I designed this board for and the extra wide wide point forward is working out good for getting forward on the board to promote speed on flat sections.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Nov 05, 2015 6:17 am
by bgreen
Keith,

Is this the place we surfed on that small onshore day? There is some interesting footage of smaller handplanes in Hawaii getting some impressive lift.

Bob

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Nov 05, 2015 10:37 am
by nomastomas
I like photos of p-boards on clean, little waves. The scale is just right.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Nov 05, 2015 2:50 pm
by krusher74
bgreen wrote:Keith,

Is this the place we surfed on that small onshore day? There is some interesting footage of smaller handplanes in Hawaii getting some impressive lift.

Bob
No this is Sker, the one you came to that was 4ft plus that early morning when you were in cardiff. :D

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Nov 05, 2015 4:06 pm
by bgreen
I really wish I'd walked back down that track and taken some waves photos. As tough as the sand walk was it would have been way more fun than doing circles are cardiff with a dying GPS.

It's funny how those two waves look so different - the top a bit crumbly but the bottom one does look like S. Those inside boulders were a killer.

Bob

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Oct 27, 2016 3:23 pm
by krusher74
Got some shots of me on this board at a local reef break last week, was trying to do some stand up surfer style off the tops, surprised from the photos how in the lip i got as finless and print this 180 turn is hard. still enjoying and using this board regularly. The green foam, 6oz, 4/6oz top had held up very well.

Re: SDF no4 (US blanks green Pu 5.10RP)

Posted: Thu Oct 27, 2016 3:58 pm
by nomastomas
You have a good photog. Seems to know what would make a good surfing action shot. Board seems to be working pretty well, too.