How can I tell if the boat has osmosis while in water?

[eranb2]

is there a way to tell if a boat has osmosis while in the water?

How can I know if the bronze thru-hulls have corrosion while the boat is in the water?

 

[tyce]

oh dear

 

[srp]

Difficult to be certain of either if its in the early stages. Very advanced cases of either problem can manifest themselves as a sort of sinking feeling....

 

[Phoenix of Hamble]

short answer.... very difficult.... you may be able to tell if the seacocks are corroded through electrolysis if they show very pink when scraped, but that it likely to be a very late stage/almost terminal case... and really you need to have her lifted out to get any proper opinion.....

 

[Malcb]

[ QUOTE ]
Difficult to be certain of either if its in the early stages. Very advanced cases of either problem can manifest themselves as a sort of sinking feeling....

[/ QUOTE ]

As far as we know, osmosis has never caused a boat to sink /forums/images/graemlins/grin.gif

Causes the bank balance to sink, but not the boat /forums/images/graemlins/laugh.gif

 

[Lakesailor]

[ QUOTE ]
is there a way to tell if a boat has osmosis while in the water? <span style="color:red">Nigh on impossible; and why? It's no big deal, unless huge chunks of gel coat are popping off. </span>

How can I know if the bronze thru-hulls have corrosion while the boat is in the water? <span style="color:red">Much more important, really need to remove one, so need to be out of the water </span>

[/ QUOTE ]

You don't say if it's your own boat or one you are looking at. More information needed on queries.
If it's a tidal situation and you can dry out, you can gather together all the needed equipment, plus an emergency blanking plate arrangement, and replace a suspect thru-hull fitting. If it's suspect you may as well as they aren't desperately expensive. But sinking is.

 

[William_H]

You don't say where you are located. In warmer waters I spend a lot of time swimming around my boat with mask and snorkel.(and cleaning rag or scouring pad)
If the bottom is clean you may (only may) feel little bubbles of osmosis with your fingers.
Similarly you may get a feel for the condition of the outside of bronze fitting by scraping or stabbing with a sharp implement.

My guess is that you want to buy a boat without lifting it out of the water for inspection. Well the price would want to be right to allow for possible /probable osmosis and fitting detriation.

If you already own the boat then don't worry about osmosis until you do lift out (or dry out) however you will not relax until you have some idea of the condition of bronze fittings. So get a wetsuit and plunge in. You can do a lot while holding your breath or within reach of a snorkel. good luck olewill

 

[john_morris_uk]

I wish we all lived in areas with the sea-water as warm as yours Will!!

My feeling is that if the fittings are true bronze, it is unlikely that they have corroded. On a previous boat the cockpit sea-cocks were over fifty years old and as good as new. Its worth a look and a bit of a scrape and a tap with a hammer though. Why not dry out against a wall?

 

[Birdseye]

you cant

 

[graham]

A boat with high water content in the GRP may not show any visible signs of blistering yet. Only drying out and having someone who knows what their doing with a moisture meter to look at it will give you a verdict.

Re the through hull fittings,Any obvious corrosion would be seen or felt by a diver but is it worth it?

 

[SteveSJM]

Agree totally with Lakesailor and malcb, forget about it and sail. Look at it next time the boat is out the water, osmosis is a disease, not of the grp but of the mind!!

It will seep into your brain more then your hull, and no matter how much money you through at curing it, it will never go, just like steel and oxidisation.