"Harryk" wrote in message
...
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




The best way to avoid the osmotic problem is not to buy a used boat that
has it, and to carefully research its appearance in brand names of new
boats.

I loved how those selling boats and boat brokers used to say, and perhaps
still say, "it's just osmotic blistering' it's not a big deal." Bull****.

Oh...balsa deck underlay. No thanks.





Another used boat to avoid is one sold with the caveat - fresh bottom - new
barrier coat. LOL! That means the blisters will be soon popping up AGAIN.
Especially with this new poppycock about spraying the hull a few times to
get rid of the trapped osmotic fluids. ROFLOL!

Wilbur Hubbard