Hows that thing float?

General Discussion
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In an attempt to not sound too authoratative (my physics has been many years past and I do software at NASA not physics)… as stated in the previously mentioned thread… something like “putting the myth to rest”… Rich is right about the displacement/boyancy/float… but there is another factor that the comes to play. While the boyancy/float factor of displacement/weight plays a small roll in proportionally speaking the weight difference is minimal and the relationship is essentially linear… The rate the lighter object accellerates to the surface is an expendential relationship with respect to its change in weight/displacement relationship.

What does all this theory mean in the real world… a slightly lighter board (eps vs pu) will float about the same meaning little to no difference when paddeling (except in how chop defelcts the board), but when riding the board and duck diving the board will want to pop or return to the surface more quickly. This is part of what gives the corky feeling. When you go to set a rail it will tend not to stay set as deep or as long. Perimiter rails/stringers will help with this a little as the weight will be out at the edges/rails helping to sink/set a rail.

Quote:
I'm also happy you mentioned something about Resin Research's flex standard. I have not read anything about that on this site before now.

as for the flex of different epoxies… several of the balsa composit sandwich threads have talked about this. Greg has 4 different flexes available in Resin Research epoxy. 1980, 2000, 2020, 2040. 1980 the stiffest and 2040 the most flexible. 2000 and 2020 being the more common with 2000 being the baseline standard RR epoxy. DanB’s “9 foot 12 pound” thread is one that talks about the use of different resins flexes.

22

4est,

Thanks for the information I was looking for. Float of a board has nothing to do with a board when it is planing. Take a skim board made out of fiberglass. It is heavier then water and will sink if left to float. However, it rides on the water when it is planing at speed. It is hard to understand the dynamics of a board in the water because there are so many variables, boards weight, wetted surface on the wave, the weight of the person riding the board, rail design and how deep it can be places under water, fin types and the most important where are you on that wave. I have not had any problem with the chop with the 3 Surftechs I own. Even the Robert August 10’ Mickey Doyle Waterman Series. As I said in other posts I weight 250 lbs. I also ride my 10’ board in 12’ surf when we get the rear clean day with that size in the fall. Yes I use it for speed to paddle out in big surf. My point being the float doesn’t have much of an effect once you are on the wave and up to speed. It is getting the dimensions to allow you to get up to speed faster and easier. This is what I was building my boards for since I had the opportunity to do it. I will find out soon how the different weights and materials change the boards dynamics in the water with a good southern hemi swell in Costa Rica. The other variable will be the East Coast wind swell I normally surf in the summer. Thanks again for the information I was looking for. I think it put floatation in a better perspective of when it is needed.

Timmmyyy