Author Topic: 7-0 Lunch Tray proposal  (Read 8407 times)

magentawave

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Re: 7-0 Lunch Tray proposal
« Reply #15 on: April 23, 2015, 12:47:36 PM »
I hear ya but I don't think a discussion of bottom contours is complete without discussing rocker. Take two seemingly identical boards with the exact same outline, length, thickness, rails, volume, bottom, etc. and tweak the rocker on one and you'll have two boards that behave radically different.

Backyarders might not fully understand the what and why but lots of professional shapers use concaves to give the effect of "flattening" rocker for down the line speed and especially if the board has flat panels on each side of the concaves. The water being channeled through the concaves makes the board scoot up a bit as if it's on rails whereas a flat bottom board with the same rocker will tend to push the water.



To clarify for others, we are talking about flat as opposed to concave with regards to bottom contours (side to side). It has nothing to do with rocker.
Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

anonsurfer

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Re: 7-0 Lunch Tray proposal
« Reply #16 on: April 23, 2015, 02:20:18 PM »
I would go with some toe in to increase responsiveness on this small board.  I'd also use the ProBox fin system so you can adjust the cant to your preference.

I have played around with 0-8 degree cant with everything else identical (same board and fins) and 4 degrees vs 0 degree cant makes a big difference.
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Biggreen

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Re: 7-0 Lunch Tray proposal
« Reply #17 on: April 23, 2015, 03:04:30 PM »
Are you able to sell the boards you build for at least what they cost you to build? What is your total cost to build a board including everything?

That said, I'm not worried about turning out a dud on my way to zeroing in on what I like.

Sorry I'm so slow to respond magenta, I just saw this.  Having already acquired or already having all the board building tools, I think a board runs about $350 for up to 8'. I'll have to do the math again and check and get back to you.  So yeah, I can easily get my material cost out of one. 

55N you've started a discussion I have long wanted to make a thread about, and I'm glad you have. It'd be interesting to hear everyone's thoughts/favorite rocker, rail thickness, etc. I'm finding I'm liking certain characteristics more than others, so if you don't mind me jumping in your thread, I'm gonna run with it.

I have slow, gutless, choppy surf often and ride on average a 7'4"x 27" board.  I will build a shorter board but I'm finding my 7'4"ish length is a good compromise of short but can obtain speed length and not fight the front to back shift with bumpy surf. I can ride narrow if I use a fuller (carry the deck out further then angle down) low apex rail. Too thin, too much fight in bump. I generally use a slight concave in the nose leading to flat through the middle and a flat panel V out the back. Nothing fancy. The Vanguard board I have has no V out the tail, but has a channel. Works great, too.  I'm normally using about 5 1/2" of nose rocker and  I think around 2 7/8" of tail rocker (I'd have to check again).  I've also come to find that on the sub 8' boards I do better with around at least 20" of nose width (12" back) and say 18 1/2" of tail width (12" up) with 17" being my minimum for my surf. None of what I've said is an absolute, is subject to change and will, and is what I'm finding works for me, not claiming it will work for others as well. I've come to this surf party late in life and find this board building/design fun and fascinating, and I love reading about it and doing it. I'm fortunate to have a surf buddy who's been surfing for more than 50 years. He doesn't preach "this works, that doesn't", he'll give his intelligent 2 cents and then say "try it". It's why I'll try some design...just cause I want to see how it'll go.

Be great if some of the other guy/gals that build or ride custom or production would measure and post what they like/works for them, their size, their surf and ability.

Get started! We can't wait to see what you produce!

55NSup

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Re: 7-0 Lunch Tray proposal
« Reply #18 on: April 24, 2015, 08:36:13 AM »
my understanding of a panel V on tail is that rocker at rail is mire than rocker a center. Board can tip on tail and rocker increases. Makes sense to me it would turn easy.

But a concave at tail or center channel would mean more rocker in center and to get board on rail it has to be more Aggressively buried because the tail is essentially inverse V. I don't understand why this works.

magentawave

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Re: 7-0 Lunch Tray proposal
« Reply #19 on: April 24, 2015, 11:59:47 AM »
55NSup - I agree with your take on V in the tail but I don't understand how a concave (or concaves) running down the center with flat panels on each side at the rails would increase rocker in the center of the board? I'm thinking of the concaves Daniel Thomson is putting in his Evo. (I want to take an 8' straight-edge with me the next time I go to a surf shop and run it along the center of a few boards to check this out.)

Below is the Tomo Evo:
« Last Edit: April 24, 2015, 12:05:57 PM by magentawave »
Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

55NSup

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Re: 7-0 Lunch Tray proposal
« Reply #20 on: April 25, 2015, 01:54:02 PM »
If a single concave or channels is deeper at center than at tail,  then yes, concave at rail is more than at centerline. Assuming relatively straight outline. This does not apply to double concave.
Boards I'm wondering about are almost flat at wide point and have concave at tail. So rocker is greater at centerline than rail. How is this promoting turning?

magentawave

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Re: 7-0 Lunch Tray proposal
« Reply #21 on: April 25, 2015, 07:59:00 PM »
Why wouldn't double barrel concaves "flatten" the rocker like a single concave?

If a single concave or channels is deeper at center than at tail,  then yes, concave at rail is more than at centerline. Assuming relatively straight outline. This does not apply to double concave.
Boards I'm wondering about are almost flat at wide point and have concave at tail. So rocker is greater at centerline than rail. How is this promoting turning?
Pluto Platter: 7-10 x 29.25 x 4.25 x 114.5 liters

55NSup

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Re: 7-0 Lunch Tray proposal
« Reply #22 on: April 27, 2015, 10:27:31 PM »
They could if spine in center is lower than rail.

55NSup

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Re: 7-0 Lunch Tray proposal
« Reply #23 on: April 30, 2015, 03:38:02 AM »
So I ordered the composite materials from easycomposites this week and picked up some eps in 100x1200x2400 size. Could only get the 100kpa stuff which is under 1,5lb ft3. Worked on the 10-6.

One day I'll get a big 4x1x1 meter block from Stockholm. Storage is a problem...ta

Will use 15mm CF tow ribbon and glass laminate.
2 x200 g bottom,  3x200 g top. Plus 2 strips of the cf each side.
Will try colored lamination,  cut lapps and clear epoxy hotcoating. 

Just gotta finish the paint job on my boys 10-6, it's 12 steps to do his Atletico Madrid, Captain America graphic mash-up. 

 


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