Osmosis repair.

[Sneaky Pete]

Been looking at a Hanse 370 with a view to buy. It has had osmosis below water line which has been attended to with the hull being epoxied again and antifouled after repair.
I will appoint a surveyor eventually in the interim would there have been a report on what was carried out of the repair and should I be looking for any other information. This is unknown territory for me.

 

[rotrax]

That is not the way to deal with osmosis. Putting an epoxy coat on top of osmosis without removing the gelcoat, treating and drying the mat, re-gelcoating and THEN re-epoxy and antifoul will just seal the moisture in.

Hayling Yacht Company do lots, the above is how they do it. It can take months.

 

[Tranona]

Difficult to comment without having the schedule of work carried out. Hopefully identifying the extent of the osmosis, the remedial work to the hull and the new coating. "attended to" covers a multitude of sins!

 

[JFowler]

Hanse 370 is a modern boat & I’m very surprised it’s subject to Osmosis.
I thought Osmosis was a something that affected 70’s / 80’s boats?

 

[Refueler]

That is not the way to deal with osmosis. Putting an epoxy coat on top of osmosis without removing the gelcoat, treating and drying the mat, re-gelcoating and THEN re-epoxy and antifoul will just seal the moisture in.

Hayling Yacht Company do lots, the above is how they do it. It can take months.

mmmm I think you are assuming something ??

Op says : "attended to with the hull being epoxied again and antifouled after repair."

 

[Refueler]

Hanse 370 is a modern boat & I’m very surprised it’s subject to Osmosis.
I thought Osmosis was a something that affected 70’s / 80’s boats?

Wrong ...

Yes the resin formulation used changed to reduce the incidents of Osmosis - but it was never stopped completely. The main matter is not so much the layup - but the Gelcoat ...
The Gelcoat can still blister - while the underlying layup resisting effects for longer.

 

[jwilson]

Hanse 370 is a cored hull, probably built between 2005-2010. I'm sure the gelcoat used will be the newer and more osmosis resistant vinylester or isopthalic resin: what inner laminate was used is not known. Some builders use cheaper resins for the laminate itself. Hanse don't seem to state what is used. The 370 did have an option of an epoxy hull, but I doubt many were built with that option.

I can only assume the boat was left afloat long-term. Many people assume modern GRP is immune to osmosis: it's not, just better than 1960s/70s/80s GRP.

Get a good surveyor......

 

[RunAgroundHard]

If the boat is out the water, and has been over the winter, then the surveyor should obtain low moisture readings, if they are moderate or high, then moisture remains trapped in the laminate which may or may not mean a future issue. If the boat is in the water and gets lifted for the survey, then moisture readings are likely unreliable.

I note you are near Faslane. If possible try and contact Ian Nicolson, one of the best surveyors there are, whom I think is retired, he will be getting on in years now.

 

[Sneaky Pete]

That is not the way to deal with osmosis. Putting an epoxy coat on top of osmosis without removing the gelcoat, treating and drying the mat, re-gelcoating and THEN re-epoxy and antifoul will just seal the moisture in.

Hayling Yacht Company do lots, the above is how they do it. It can take months.

Sorry should have clarified what I have been told was done. Yes it was dried out and the area or area's had the damaged material removed and re-geled.

 

[Sneaky Pete]

Difficult to comment without having the schedule of work carried out. Hopefully identifying the extent of the osmosis, the remedial work to the hull and the new coating. "attended to" covers a multitude of sins!

That's the purpose of the post was to see if I should be seeking more detailed info on what work has been carried out, a work schedule would be a good starting point. Not bothered with the fact there has been osmosis providing it has been properly rectified and problem cured.

 

[Refueler]

"it has been properly rectified and problem cured."

Sorry but that is not possible ... all Osmosis work - even full scale peeling and epoxying is not a cure ... its a delaying tactic that extends the life of the hull.

It is basically why over the years - full scale peeling and such has been less frequently done ... the change being to more of .. grind - fill - epoxy - paint.

 

[Fr J Hackett]

That's the purpose of the post was to see if I should be seeking more detailed info on what work has been carried out, a work schedule would be a good starting point. Not bothered with the fact there has been osmosis providing it has been properly rectified and problem cured.

Yes do exactly that, who repaired it, what was the extent and how was it done then you can decide was it localised, was it a quick cosmetic repair etc and make your decision on that basis.

 

[Tranona]

That's the purpose of the post was to see if I should be seeking more detailed info on what work has been carried out, a work schedule would be a good starting point. Not bothered with the fact there has been osmosis providing it has been properly rectified and problem cured.

There is really no permanent cure only extending the time of blister free. There may be some from of guarantee from the contractor. At this point the best you can expect is evidence that the work was carried out correctly. Your survey will hopefully determine the current situation and whether the remedial work has been effective.