Weight Matters

[sflinux]

And how about the the relationship of center of mass relative to the pivot point of the swing weight?
Erik Antonson commented that he likes to slide his mast forward in the box to minimize swing weight for pumping.
He commented that the heavy weight of a SUP wasn't a negative thing when the mast was moved forward in the box, but was when it was further back in the box. 
The KD Maui foil mast placement of holding the foil at 1/3 back [center of pressure] from the leading edge from the front foil and have the board be level (upside down).  Erik is moving his mast more forward relative to this setup to make pumping easier.
https://soundcloud.com/progressionproject/foil-series-ep-7-kane-dewild 23'
https://www.youtube.com/watch?v=SVgOg8r6zbg

[PonoBill]

I've never thought Kane's rule of thumb made any sense, but then he can foil circles around me, so I'm not in a position to make a big deal about that.

[Dontsink]

I just sold a 5.0 wingfoil board because it felt too heavy.Lost about 30% of the money i paid for it new
Loved the shape,track placement, the build quality,the specs...but i could not get used to the bigger weight and the sluggish inertia it created.
On a digital scale the difference was a ridiculous  +700 grams compared to what i am used to riding.
Sounds like nothing but it completely changed the feel in any conditions, way less fun and responsive.
In light wind it really affects the bottom end.

[Hdip]

Sounds like the weight doesn't matter, but the shape does. People are obsessed with the idea that "the board doesn't matter" in foiling. We've got to stop saying that. The shape definitely matters.

[jondrums]

I've never thought Kane's rule of thumb made any sense, but then he can foil circles around me, so I'm not in a position to make a big deal about that.

My own experimentation has landed in the same spot as Kane's rule.  Mind you this seems to be the optimum for pumping performance doing 2 for 1s and the like.

[blueplanetsurf]

The reason for balancing the weight of the board over the foil is so the board will fly by itself when it's unweighted.  This is crucial for dock starts and pumping.
This video shows how a well balanced foil mount will fly without tipping forward or backward:
https://youtu.be/_WPJ8kvsnLM?t=1471

[Beasho]

Back to the Weight. 

Here is a Matrix that shows what a board would weigh with:

1) 2X Layers of 6 oz Carbon around the whole board - This would be bomber AKA Heavy Duty.  12 ounces per yard of CARBON Fiber. 
2) 60% : 40% Carbon to Resin Ratio - This is what results from a vacuum bagging process
3) Assumed 2 lbs for TRACKS and reinforcement.  My latest TRACK Cassette was 19 ounces.  This leaves 13 ounces for reinforcement.

At this build schedule a 120 liter board with 1 lbs EPS foam (standard) would be 9.9 lbs. 

I have observed that most production boards come in 5 lbs heavier than these numbers.  And the manufacturers do not even post the weights (with some exceptions)

WHY? 

It comes down to construction method, and PAINT.  And when you do a minimal amount of research into Fiber to Resin ratios you will learn that heavier, non-vacuum bagged solutions are in fact heavier, more fragile and weaker.

Board shapes will change. 

These production methods have been around for 30+ years.  Windsurfers know, and remember the lightweight customs that used to come out of the Gorge in the late 80's and 90's.  Example HiPer Tech, Clam Sandwich . . . . 

[PonoBill]

Gary Efferding (HiPer Tech) is still around in Hood River, still making amazing stuff out of composites, but he mostly does it for Insitu -- the drone company Boeing owns. I need to get him involved in some of the stupid projects I'm pushing forward. He's endlessly enthusiastic. The only problem is that when we get together it's an ADHD idea fest, and neither of us gets anything done.