Moisture in Hull

[lindabarzini]

If a boat has been sitting on the hard for 5 years, can a surveyor still detect moisture in a hull with a moisture meter?

[yeloya]

If there has been a moisture in a hull, after 5 years visible blisters , uneven surfaces should have been detectible. As surveyor would also make a control with a rubber hammer to check for the delamination beside measuring the humidity. Every high reading doesn't necesarily means that there is a an osmosis; many new boats that are made with a vacuum infusion technique, give relatively higher readings as a result of chemicals added to polyester to make this process easier. This is particularly the case if ortophatalic resin (which is cheaper and thicker) is used.


Cheers


Yeloya

[Sid at SailAway]

Absolutely. Even on the hard, boats are susceptible to water intrusion from the rain and poorly bedded or lose fittings. Are you looking at a boat that has been on the hard that long or is this a I'm curious question. Five years is a long time to be on the hard...

[maxingout]

I would get out the hammer and check for delamination.

[zeehag]

i know an honest surveyor who states moisture meters are too inaccurate to use.
after 5yrs on hard there should be no moisture in hull unless you have a leak from topsides making it so.
5 yrs on hard tells me- does not float-- run, do not walk , away. fast and far, there are way too many boats for sale to sit and mope over one with issues.
if it were in water, it would be open for consideration.

[undercutter]

Every raw water system on the boat will likely be seized and probably fresh water ones as well. I am with Zeehag, run away!!!!

[geoffr]

We've been on the hard with very very dry winters for 5 years (major refit with no time ) and I checked the hull with a moisture meter. I saw varying readings and I know it's not rain water intrusion and I assume it's not water but the lay-up or something causing the higher readings.. (eg rudder post showed water).

[TOT]

We just left Thailand a month ago and l saw some SHOCKING conditions on boats that had been left on the hard stand for only 2-3 years as it appears some owners just bring them ashore and forget them.

Be very careful and buy a good pair of running shoes 😎


SV TOT
Wayne 😃

[rabbi]

If there is moisture in a cored hull after 5years on the hard it will be from leaking deck fittings. I'd expect rot and / or delamination in that case. No need for fancy moisture meters, a surveyor can hear it by tapping the hull.


Non-destructing moisture meters cost just about 100-150 euros and can help to quickly pre-screen boats but can not replace a surveyor. I'm not an expert but bought one of these when I was in the market for some real estate. So naturally I played around with it at the boat.

Even to pre-screen you need to know how to use it, and especially how to interpret the values it gives. Different surface shapes, layups, interior panels, bulkheads, fittings etc all change the reading. It really is most helpful on the flat areas of the hull.
The areas around deck fittings are prone to water intrusion but also hard to analyse with such a moisture meter. Is the high reading because of water or because there is a metal fastener??



Anyway after 5 years hardstanding any boat will be good for nasty surprises on the sea trial.
It should be clearly stated in writing who pays for making the boat ready for seatrial (like engine maintenance, seacock checks, new batteries, etc) and who is liable should anything go wrong (like sinking after a hose breaks). I'd expect the buyer to pay only for the travel lift and surveyor.

It should better be a very good deal to make this excercise worth it.

[44'cruisingcat]

Originally Posted by geoffr

We've been on the hard with very very dry winters for 5 years (major refit with no time ) and I checked the hull with a moisture meter. I saw varying readings and I know it's not rain water intrusion and I assume it's not water but the lay-up or something causing the higher readings.. (eg rudder post showed water).

Well, you better run away!

[boatpoker]

Moisture meters will show high readings. caused by fluids other than water.
Hydrolytic fluids caused by resin dissolving in reaction to water will show up after 50 years on the hard let alone 5 as it cannot evaporate.

The earlier poster mentioned a rudder stock showing high moisture. Moisture meters do NOT measure moisture ! Metal or metallic materials will cause high readings. If interested I have a complete explanation of moisture meters, how they work .... and how they don't work along with many examples and photos.
Take a look at Moisture Meter Mythology.

[HankOnthewater]

Boatpoker:
Thank you that link, interesting read, although I still don't understand why the author uses 'capacitance', instead of 'resistance'. Although I have limited knowledge of these meters, I think he makes some good points.

Linda (OP):
All subsequent posters assumed that you were referring to a fibreglass boat. Is that correct? I don't know if your question will have a different answer with other construction methods: ie cored hulls, cold moulded, or stripplank.
I am pretty sure your question does not refer to steel or aluminium boat.
And what about a wooden hull, ie carvel built?

I agree with other posters that believe that 5 years of non-use (is that neglect or worse?) will cause many items to fail.

[rabbi]

capacitance is what these meters measure, not resistance
resistance is only used by those cheap meters which have spikes to press into wood. they don't work on hulls


as for hull material.. this is the mulltihull forum so it's fairly unlikely to find anything but fibreglass.

[HankOnthewater]

Thank you Rabbi, I proved my ignorance regarding those meters in my previous post.
And obviously I did not check the subforum heading. Will do that in future.

[boatman61]

Originally Posted by rabbi

capacitance is what these meters measure, not resistance
resistance is only used by those cheap meters which have spikes to press into wood. they don't work on hulls


as for hull material.. this is the mulltihull forum so it's fairly unlikely to find anything but fibreglass.

Don't tell Wharram that. he's been calling his boats Catamarans for years.. the shock of finding out he's not a Multi-huller could kill the old buga..
And they call mono people 'Prejudiced'..