[Rhodes22-list] Biological Centerboard Fouling/Jamming - A Serious Issue?

[Jim White]

Robert:
Most invertebrate marine organisms can only tolerate rapid, heavy salinity 
changes for short periods. Barnacles, which are actually closely related to 
shrimp and lobsters (they're crustaceans) are one which are pretty 
sensitive to these changes.

So sailing up into  fresh water and remaining there for a bit of time would 
kill the organisms on ones hull. The barnacle "shell" is composed of 
calcium carbonate, that over time would dissociate in fresh water 
(especially fresh water with a slightly acidic pH), but I have doubts as to 
whether they would actually fall off.....probably most of the oldtimers 
would scrape along the bottom a bit, dislodging things. Barnacle 
attachments, once firm are pretty secure.

I have also heard of this method used down South (I believe in the Rio 
Dulce region of Guatemala), where the local fisherman bring their boats up 
the fresh water river during the off season, mooring them there. 
Anecdotally, they say that during the off season fresh water growth begins 
to colonize, then when they return to sea, it dies and the process starts 
over. Sounds like a good method of biologic control.
jw
Jim White
Le Menagerie

At 06:22 PM 12/3/2004, you wrote:
>Jim White wrote:
> > ...
> >   A week (or two) in most saltwater areas is no big deal, and even here
> > where the water is pretty warm year round (seldom gets below low 60's)...
> > If you don't leave your boat in the water for extended periods, and don't
> > bottom paint, I certainly wouldn't consider doing that for a short stay in
> > the briney such as you have described.
>
>Historically in the Chesapeake and in Maine, sailing up a
>river into fresh water for a week or so was/is supposed to
>cause barnacles to fall off.
>
>Is there any truth to this?
>
>/Robert Skinner
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