Author Topic: thick dark strip on bottom of foil boards  (Read 647 times)

liv2surf

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thick dark strip on bottom of foil boards
« on: September 22, 2020, 10:33:40 PM »
what is the composition and function of the thick dark strip to the nose-ward side of the foil boxes visible on the bottom? I have a production board with two full length 1/4" stringers connected to the outer side of the foil boxes.
6'6" CRUZ 'CIM' Wing Foil SUP (130L)
9'6" CRUZ Surf foil SUP (152L)
Cabrinha Crosswing X2 4m, 5m, 6m
Axis 1020; Axis 1150, standard fuse, 500 stab
65cm (and 90 cm) Project Cedrus carbon mast
Chinook Thrust 92 Paddle -- fixed 78" length
Me: 190 lbs, 64 yo Half Moon Bay, CA

DavidJohn

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Re: thick dark strip on bottom of foil boards
« Reply #1 on: September 22, 2020, 11:06:34 PM »
Iím guessing itís carbon fiber and there to add stiffness to the board.

The glass or skin on the bottom of boards is usually very thin because the surface is supported evenly across the whole bottom buy the water and itís usually under tention like when you stand in the middle (on the top) pushing down but if you were to flip the board over and stand on the bottom this puts the bottom skin in compression and a crease would normally be the result..

Iím thinking this carbon reinforcement strip not only acts like a stringer but protects against these tension/compression forces.

surfcowboy

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Re: thick dark strip on bottom of foil boards
« Reply #2 on: September 23, 2020, 03:56:56 PM »
It's carbon, yes. And think about pumping. Unlike standing in the middle on a surfboard which is stretching the bottom skin, you are actually potentially compressing it (greatly) if you have your feet apart and press down hard which you do while pumping. Especially if you're bridged with a foot behind the mast.

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liv2surf

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Re: thick dark strip on bottom of foil boards
« Reply #3 on: September 23, 2020, 10:18:42 PM »
My no-name 'production' foil board has 2@ 1/4" thick parallel stringers on the outside of the foil tracks (foil tracks are installed up against these) which go tail to tip and I think goes from bottom to deck (they show on the bottom, I can't tell if they are full depth).  These would seem to be low tech analogs of the carbon in the picture?
6'6" CRUZ 'CIM' Wing Foil SUP (130L)
9'6" CRUZ Surf foil SUP (152L)
Cabrinha Crosswing X2 4m, 5m, 6m
Axis 1020; Axis 1150, standard fuse, 500 stab
65cm (and 90 cm) Project Cedrus carbon mast
Chinook Thrust 92 Paddle -- fixed 78" length
Me: 190 lbs, 64 yo Half Moon Bay, CA

surfcowboy

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Re: thick dark strip on bottom of foil boards
« Reply #4 on: September 24, 2020, 01:24:41 AM »
Yes, stringers for stiffness. But in that case they are also likely tying the boxes to them so they serve 2 purposes, stiffness in the board and keeping the foil from ripping the boxes out. My orange board is constructed like this.

liv2surf

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Re: thick dark strip on bottom of foil boards
« Reply #5 on: September 24, 2020, 07:22:18 AM »
I believe I have heard that with foil boards there is a desire to link the foil forces to the deck and board so it can be more effectively linked to the rider. Does this make sense? Can anyone articulate this better?
6'6" CRUZ 'CIM' Wing Foil SUP (130L)
9'6" CRUZ Surf foil SUP (152L)
Cabrinha Crosswing X2 4m, 5m, 6m
Axis 1020; Axis 1150, standard fuse, 500 stab
65cm (and 90 cm) Project Cedrus carbon mast
Chinook Thrust 92 Paddle -- fixed 78" length
Me: 190 lbs, 64 yo Half Moon Bay, CA

liv2surf

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Re: thick dark strip on bottom of foil boards
« Reply #6 on: September 24, 2020, 07:23:55 AM »
what is the CONSTRUCTION of the thick dark strip to the nose-ward side of the foil boxes visible on the bottom? Is it a foam wedge wrapped in carbon dropped into a recess?
6'6" CRUZ 'CIM' Wing Foil SUP (130L)
9'6" CRUZ Surf foil SUP (152L)
Cabrinha Crosswing X2 4m, 5m, 6m
Axis 1020; Axis 1150, standard fuse, 500 stab
65cm (and 90 cm) Project Cedrus carbon mast
Chinook Thrust 92 Paddle -- fixed 78" length
Me: 190 lbs, 64 yo Half Moon Bay, CA

TallDude

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Re: thick dark strip on bottom of foil boards
« Reply #7 on: September 24, 2020, 08:26:27 AM »
It looks like a painted graphic. Maybe exposing a bit of CF for that sense of strength. They sound like they are built pretty strong.
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I rarely use.

 


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