Survey hull moisture readings - what does it mean?

[chris-s]

In our tentative search for our second boat, I am now more aware of what osmosis is than I was four years ago when we bought our first boat, at that time I had never heard of it and the value of the boat didn't warrant a survey. I would not be afraid of tackling blisters myself, but would never want to take on a boat that required a full hull strip as I'm quite sure the costs would be far too prohibitive.

For one boat that has gotten our interest, the broker was able to let us have a copy of the last survey to at least give some indication of the state of things when the current owners purchased her. This is the first survey report we have ever seen, and I' m interested in how those of you with more experience would view the moisture readings or how they might compare to similar boats. Granted, this report is several years old, and the state of things will be quite different now, especially if no remidiation has been carried out in the meantime, but the reason for asking is not to help our understanding, not nescessarily for this boat, but for future surveys we may see or commision.

The boat is a mid-eighties Westerly, at the time of the survey, she had been ashore for about three years. To summarise the report, twenty areas of the hull were scraped back to gelcoat, six of which had small gelcoat blisters. A few others showed signs of blister repairs around 2-3cm in diameter. Using a Tramex Skipper Plus meter set to scale two, readings of 50 to 70 on the 100 scale were measured. After standing ashore for a number of years, the surface laminate has had the opportunity to dry. The Tramex meter reads deep moisture content and is evidence that the hull has retained a relatively high level of moisture whilst standing ashore.

How would you view these readings?

Thanks

Chris

 

[Poecheng]

How would you view these readings?

A: With concern. And then run...

 

[Plum]

In our tentative search for our second boat, I am now more aware of what osmosis is than I was four years ago when we bought our first boat, at that time I had never heard of it and the value of the boat didn't warrant a survey. I would not be afraid of tackling blisters myself, but would never want to take on a boat that required a full hull strip as I'm quite sure the costs would be far too prohibitive.

For one boat that has gotten our interest, the broker was able to let us have a copy of the last survey to at least give some indication of the state of things when the current owners purchased her. This is the first survey report we have ever seen, and I' m interested in how those of you with more experience would view the moisture readings or how they might compare to similar boats. Granted, this report is several years old, and the state of things will be quite different now, especially if no remidiation has been carried out in the meantime, but the reason for asking is not to help our understanding, not nescessarily for this boat, but for future surveys we may see or commision.

The boat is a mid-eighties Westerly, at the time of the survey, she had been ashore for about three years. To summarise the report, twenty areas of the hull were scraped back to gelcoat, six of which had small gelcoat blisters. A few others showed signs of blister repairs around 2-3cm in diameter. Using a Tramex Skipper Plus meter set to scale two, readings of 50 to 70 on the 100 scale were measured. After standing ashore for a number of years, the surface laminate has had the opportunity to dry. The Tramex meter reads deep moisture content and is evidence that the hull has retained a relatively high level of moisture whilst standing ashore.

How would you view these readings?

Thanks

Chris

High moisture content does not mean osmosis is inevitable. If everything else about the boat is good then I would get a quote from a reputable osmosis treatment yard and use those moisture readings and your quote to justify a suitable offer. If the seller does not accept then you can walk away. If they do then buy and go sailing knowing that if osmosis appears at a later date you can get it fixed with the money you saved and using the receipt from the osmosis yard you will be able to get a good price when you sell in the future.

www.solocoastalsailing.co.uk

 

[Stemar]

Osmosis is, from all that I can gather, a way for boatyards to make money. Unless the blisters are really big, it isn't structural, and doesn't mean a great deal unless you're buying or selling, when it's a way for the buyer to get a reduced price. If the boat's been standing on the hard for a few years, has rainwater got in and sat in the bilges? This would explain a high moisture content

If the boat's right in all other respects, I'd use the osmosis to get a good price, then grind out the blisters and fill with epoxy over winter and go sailing in the summer. It's likely that a few more blisters will appear and I'd deal with them in the same way when I could be bothered.

 

[RunAgroundHard]

They would not concern me.

The reason the hull will not dry even after years ashore is that the water molecules have reacted with one of the chemicals in the resin, which did not cure fully. The new molecule is larger than the water molecule and can not pass through the cured resin.

Two things can now happen. The new molecule just sits there and no further reactions take place as all the uncured chemical reacts. Or, the volume of uncured chemical is high and as it reacts with water, it‘s volume increases above the space and causes a blister.

From what I can tell, managing blisters on surface as they appear, every other lift out, is likely the best way to treat. A boat this age is not likely to deteriorate further.

If the boat is priced well and affordable to you, meets your requirements, is in otherwise in good order, your sailing is pottering about and coastal, then it would not bother me.

I bought aboat with similar history, previous owner treated minor blistering. None have reappeared, moisture readings have never changed when taken after 2 months ashore. Note that moisture readings have to be taken a few weeks, months after layup, with dry bilges, to allow moisture molecules that are not reacting to do their thing and dissipate out the laminate. If you take readings too early, hulls of your age, just measuring moisture as a result of being in the water, not trapped moisture. Note that resins changed around the 80’s a new resin formulas behave differently. I don’t know the names of the resins.

That’s my experience as an amateur after lots of research when buying an old GRP hull.

 

[Bilgediver]

In our tentative search for our second boat, I am now more aware of what osmosis is than I was four years ago when we bought our first boat, at that time I had never heard of it and the value of the boat didn't warrant a survey. I would not be afraid of tackling blisters myself, but would never want to take on a boat that required a full hull strip as I'm quite sure the costs would be far too prohibitive.


How would you view these readings?

Thanks

Chris

Treat as guidance regarding the price offered and not too concerned. I would get someone knowledgeable to check out the areas of high readings however having dealt with a Westerly with similar problems if this was the same and confined to the gel coat then would not be particularly concerned.

My westerly was built in 1973 and in the mid 80' s we discovered blisters in two areas between the keels and one side just above the keel pods, Everyone that viewed was full of doom and gloom however one of our club members was in charge of maintenance of the channel buoys in the river and after viewing advised it was confined to the rather thick gel coat and there were various options of filler and protection. He also mentioned that it wasn't just a matter of waiting to dry but after blasting the affected areas with I believe was a fine grit I was to wash it twice a day with warm water. I did this using a garden sprayer until the vinegar smell was no longer detectable. About 3/4 weeks. The affected areas were then filled with and International product and the whole hull covered with an International Gelshield product I believe 5 coats were applied and I think it came in two colours so you could distinguish coated areas. 35 years later there have been no further incidents of this problem. If your problem is only in the gelcoat a similar treatment maybe all that is required for peace of mind.

 

[Graham376]

the broker was able to let us have a copy of the last survey to at least give some indication of the state of things when the current owners purchased her.

You don't say how old this survey is. Bear in mind insurers will want to see a fairly recent survey (maybe up to 5 years OK) if insuring comprehensively so you may save yourself some grief by having a pre-purchase survey, which gives the opportunity of negotiating a price reduction to carry out remedial work or, walk away.

 

[Refueler]

How would you view these readings?

A: With concern. And then run...

Sorry - total over-reaction.

The Tramex is a deep highly sensitive meter that shows moisture when such as the Sovereign and its clones fail. The Tramex has scared too many people off ... but its value is in the osmosis treatment process., Its ability to read deep into the hull is its asset when drying out a hull.
It can detect water in bilges ... even to wood bulkheads that have taken up water .....

The Tramex is one of the best instruments - BUT in the proper hands. The readings should be explained and not just quoted ....

When I conducted Surveys in UK .. and occasional here in Latvia ... I have two meters .... 1. Protimeter for general checks, comparable in result to Sovereign, 2. Tramex for supervision work or new / near new hulls.

OK - Westerly .... mid 80's build ..... not unusual to have high moisture readings and blisters. Would I be worried ? Certainly not. Built like tanks ....
I would be more interested in looking at keel joints than the likely blisters !!

 

[skipmac]

First, understand the moisture meters on fiberglass do not read moisture. The technology of all I'm familiar with measure capacitance which can be effected by moisture but also a number of other factors including the kind of resin, thickness of the laminate, how well the layers of glass are bonded together, kind of core or no core and a few more.

I purchased an expensive and highly recommended meter when I was rebuilding a boat. I was able to find areas of high moister and core rot around stanchions, chain plate penetrations and similar, typically suspect spots but also had several areas where the needle pegged out to max on the scale of the meter that proved to be bone dry when I drilled into the core from below. Some, after the fact, I was able to point to differences in the glass laminate. Others I could see no obvious reason for the high readings.

Bottom line, a moisture meter is certainly useful and can give an indications of possible problem areas but should not be taken as the final answer. Also, finding some blisters in the hull is not necessarily a deal breaker. It will depend on the size and extent of the blisters and other factors.

In addition to a moisture meter, use of a hard plastic mallet to sound the hull and deck (which is more often a problem than the hull) can be very informative and can identify areas of delamination, core rot, etc. I would use that as step two to check areas that show high readings on the meter. Also look at the interior of the boat where you get high readings. Is there a bulkhead bonded to the hull on the inside? Is it near a through hull where there could be additional reinforcing or a backing plate?

 

[Poecheng]

Sorry - total over-reaction.

If the OP wants lots of work and/or to spend money - fine. If they want to go sailing... As another poster said, it becomes an issue when buying and selling - the OP is considering one and will inevitably do the other. It sounds like the OP's first boat of some value - why would anyone encourage them to take this boat on when it is likely to need some real experience to deal with?
We don't know which Westerly but sorting that professionally could, depending on the size, be a very significant chunk of its claimed value.

The Tramex is one of the best instruments - BUT in the proper hands. The readings should be explained and not just quoted ....
When I conducted Surveys in UK ..

Well, an explanation of the readings is precisely what the OP asked for.
An explanation in the context of a boat on the hard for years and where spurious excuses for high readings can be ruled out because, presumably, the surveyor would have been looking for them as well.
That such boats were built like a tank is not to the point because they haven't asked about ultimate structural integrity accepting it has serious osmosis

 

[skipmac]

If the OP wants lots of work and/or to spend money - fine. If they want to go sailing... As another poster said, it becomes an issue when buying and selling - the OP is considering one and will inevitably do the other. It sounds like the OP's first boat of some value - why would anyone encourage them to take this boat on when it is likely to need some real experience to deal with?
We don't know which Westerly but sorting that professionally could, depending on the size, be a very significant chunk of its claimed value.


Well, an explanation of the readings is precisely what the OP asked for.
An explanation in the context of a boat on the hard for years and where spurious excuses for high readings can be ruled out because, presumably, the surveyor would have been looking for them as well.
That such boats were built like a tank is not to the point because they haven't asked about ultimate structural integrity accepting it has serious osmosis

There is certainly a concern about potential resale for a boat that truly has moisture and/or blister problems but in my experience 99% of the older boats out there will have a blister or three. So a few, isolated blisters I don't see as an issued. Plus is resale the main concern? It is almost certain that a boat is going to be an expense and over time could be a significant expense. Of course everyone's priorities are different but for many the main priority is buying a boat appropriate for his/her use and recouping the investment on resale may be very secondary.

Regarding the survey, as a former broker I've participated in dozens and advised friends on purchases and reading their own surveys. I can say with complete certainty that many, many surveyors do not have a clear understanding of moisture meters and how to analyze the results.

Based on my experience, high moisture readings and even some limited blistering can be a non issue. Not to be ignored and either should be motivation to look more closely at the boat but either or both without confirmation of the extent or seriousness of the problem would not be a deal killer for me.

 

[Refueler]

If the OP wants lots of work and/or to spend money - fine. If they want to go sailing... As another poster said, it becomes an issue when buying and selling - the OP is considering one and will inevitably do the other. It sounds like the OP's first boat of some value - why would anyone encourage them to take this boat on when it is likely to need some real experience to deal with?
We don't know which Westerly but sorting that professionally could, depending on the size, be a very significant chunk of its claimed value.

As another has posted ..... use the info to try gain reduced price ... but I would think that if Broker is passing over an old survey showing the info - price may already be reduced.
BUT - thousands of boats of that era sail happily on with such ..... owners popping blisters when brought ashore ... washing out ... filling .... launching .. sailing ... lifting out - pop a few more blisters etc.

Sorry but your quoted is harking back to the doomsayer days which thankfully have passed on ...

Well, an explanation of the readings is precisely what the OP asked for.
An explanation in the context of a boat on the hard for years and where spurious excuses for high readings can be ruled out because, presumably, the surveyor would have been looking for them as well.
That such boats were built like a tank is not to the point because they haven't asked about ultimate structural integrity accepting it has serious osmosis

So my post about the Tramex is worthless ??

Explanation of readings ? How can I provide such as I did not do the survey ... I don't know what were reference readings to compare ... I have no info to go on other than OP saying a couple of numbers.

 

[Refueler]

.......................I can say with complete certainty that many, many surveyors do not have a clear understanding of moisture meters and how to analyze the results.

"Aint that the truth" ......

Moisture Meters - particularly the Sovereign and similar are based on 'Construction Work' ... ie buildings and timber ? Its only such as the Tramex that have been developed further to deep penetrate GRP.

Some of the Meters I've seen / heard of some using are only suitable to find metal pipes . cables in walls .... as Moisture Meters ? Useless.
Many I've noted have not taken any reference readings.

I know one Surveyor who I observed, he was choosing where to meter ... choosing blistered areas .... as he had interests in the Osmosis Treatment.

 

[skipmac]

"Aint that the truth" ......

Moisture Meters - particularly the Sovereign and similar are based on 'Construction Work' ... ie buildings and timber ? Its only such as the Tramex that have been developed further to deep penetrate GRP.

Some of the Meters I've seen / heard of some using are only suitable to find metal pipes . cables in walls .... as Moisture Meters ? Useless.
Many I've noted have not taken any reference readings.

I know one Surveyor who I observed, he was choosing where to meter ... choosing blistered areas .... as he had interests in the Osmosis Treatment.

Sad to say, but in my time as a yacht broker I found plenty of surveyors that were either incompetent or just lazy and a few that were downright dishonest.

Also, let me correct a previous statement. Meters do not all work specifically on capacitance but more correctly, conductance IE how well the material conducts electricity which can be measured with various technologies. But at the end, all measure in one way or another, electrical conductivity and not directly moisture content.

 

[Refueler]

Most moisture meters make excellent Studding Detectors ...... to find metal and other in walls ...

 

[bignick]

I would recommend that you read this guide to using the Tramex Skipper Plus.

http://www.bluestarsurveys.co.uk/skipperguide.pdf

This one on osmosis is also very informative:

https://www.passionforpaint.co.uk/product_uploads/15574838191.pdf

 

[Bobc]

What it means is that you're buying a 40 year old boat. They're all like that.

 

[Stemar]

The Tramex ... value is in the osmosis treatment process.

Especially when selling the treatment.

 

[Refueler]

Especially when selling the treatment.

Think you misunderstood MY statement - but yes some others are / were using it to sell treatment .....

 

[Kukri]

Most moisture meters make excellent Studding Detectors ...... to find metal and other in walls ...

I remember having great fun with a moisture meter on a teak deck which had been secret nailed - it found every nail, but was useless for telling us the moisture content.