"Bruce in Bangkok" wrote in message
...
On Tue, 19 Apr 2011 15:56:31 -0400, " Sir Gregory Hall, Esq."
wrote:



Fact: It takes a pressure gradient on a membrane in order for osmosis to
occur.

Fact: A blistered bottom is the result of untold hours of this pressure
gradient. Sometimes it takes years of submersion which creates the
pressure
gradient for blisters to occur. Osmosis is a relatively slow process when
pressure differentials on either side of a membrane are not great.

Fact: Spraying the blistered bottom repeatedly with fresh water does NOT
create osmosis as there is no pressure gradient.

Fact: No pressure gradient = no osmosis = surface wetness only = no
penetration into soggy laminate.

Fact: No penetration = wishful thinking and NO effect upon reducing the
moisture in the soggy laminate that combines with layup chemicals.


Now, to the crux of the matter which is how to remove the moisture from
the
laminate before coating the bottom with an impermeable 'barrier coat.'

There is only one way to accomplish this drying process and that is not by
osmosis but by diffusion through the membrane and evaporation of the
moisture at the surface of the membrane. This process involves storing the
soggy layup in a low-humidity environment for a year or two so diffusion
and
evaporation can occur and the hull can be tested with a moisture meter
until
it reaches acceptable levels.

I welcome any rational, enlightened explanation of how spraying the hull
with water can possibly negate or supersede the above facts.


Wilbur Hubbard


You are making a fundamental error in assuming that osmosis is what is
happening to a boat hull. It isn't. The hull is absorbing water which
combines with residual chemicals in the laminate and has nothing to do
with a pressure gradient.

You can explain membrane osmosis until the cows come home and you are
still wrong as it is not the same process that causes blisters on a
boat's bottom.

Unfortunately, as is so often the case, you are exhibiting your own
ignorance yet again.


Bruce,

You are the one exhibiting ignorance. You seem to be suggesting that the
hull 'absorbing' water is what causes the blisters.

ROFLOL!

That's IMPOSSIBLE. The blisters MUST be caused by higher pressures inside
the laminate than outside the laminate or the blister would not raise its
ugly head against the outside pressure. If all it involved was water
absorption then the pressures would be equalized. The osmosis comes into
play because the higher density of the chemicals in the laminate on one side
of the membrane causes osmotic action between the chemicals and the water
outside. The water passes through the membrane and tries to dilute the
chemicals to the same density as the sea water. This increases the pressure
on the inside of the membrane until a blister pops up. Try to understand
what osmosis actually entails, Rube!

Freaking morons, I have to deal with around here. Absolutely NO concepts of
basic physics. No wonder most all of them have failed as sailors.

Wilbur Hubbard