Old boats and moisture readings.

[skyflyer]

If you’re buying a 25 year old GRP boat, which has no evidence of osmosis, and was (according to PO) prophylactically epoxy coated below waterline when three years old, (receipts to prove it), then how concerned should you be about high moisture readings in certain areas at pre purchase survey. The surveyor is Saying it needs to be fixed, albeit not immediately, involving removing gelcoat (including some abovecwaterline).
Additional info. The outer layers of the entire hull laminate is constructed with vinylester not polyester resin as this is (supposedly?) 100% resistant to water penetration.

 

[Kukri]

I have had the same advice from two surveyors in respect of a 47 year old boat and indeed one of them told me that the grander sort of yacht brokers always state that “the hull shows signs of osmosis”, even if it doesn’t, in order to protect themselves and their principal. ( Some will say this is picky, I know, but brokers don’t have “clients” they have “principals”.

The next owner can do it.

 

[Concerto]

Most boats that are 20+ years old will have moisture readings in the low 20's, which a surveyor will say is high. My Fulmar made in 1980 was surveyed when she was 35 years old and had readings in that range, despite having been out of the water for 18 months. Does it worry me, no it does not. Even osmosis is not as bad as many make out as it can repaired without stripping the gel coat and relaying. Many boats that have been stripped and sheathed and after about 10 years find the sheathing starting to blister again.

Personally skyflyer I think you have nothing to worry about.

 

[Kukri]

I quote the relevant sections of my most recent survey report, which may make a comparison with yours:

“Use of Moisture Meter

“A ‘Sovereign Quantum’ capacitance-type moisture meter, which measures both shallow and deep- seated moisture, was used to check for the ingress of moisture into the GRP laminate. Reference to moisture meter readings are in relation to a relative scale of 0-100, not moisture content as a percentage of dry weight. Readings of 0-15 are considered dry, 16-20 low but of no concern, 21-30 medium and approaching the point where risk of moisture- related defects developing is becoming significant, 31-45 high and at a level where the risk of moisture-related defects being present but not yet physically detectable is significant, 46-60 very high and often accompanied by physical detectable signs. A reading of 61-100 is extremely high and indicative of possible laminate damage in addition to
osmotic blistering. Readings are considered in conjunction with the period the vessel has been ashore and the weather conditions when the readings were obtained. Boats built in the last 15 years are generally far more moisture resistant.

“The encapsulated lead keel was inspected and seen to be in sound condition with no evidence of any delamination or voids in the moulding. There was no evidence of any grounding damage to the foot of the keel.

“The bottom is coated with a thick coat of white antifouling, scraping the hull back through the layers several coats of epoxy can be seen. The hull does have signs of old osmotic blistering but on closer examination there is no wicking or deterioration to the laminate. Several areas port and starboard the coatings were scraped back for inspection. Moisture readings were taken using a Sovereign Quantum moisture meter. The hull showed signs of being relatively wet but no evidence of any structural defects being apparent. The hull is a solid lay up, internal readings below the waterline were relatively dry showing the moisture content to be concentrated to the outer laminates. External readings varied from 30-45. At this stage there is no sign of any structural damage or any immediate concern. It would be recommended that within the next few years, all the paint coatings be blasted or cleaned off and steam cleaned. Re inspect the hull moisture readings, if no reduction then peel the hull back to the original laminate, blast and steam clean trying to remove the salts from the outer laminate, allow to dry. When dryer epoxy coat and re antifoul.”

 

[srm]

It might be worth establishing where on the hull the high moisture readings were recorded. According to a survey I had done quite a few years ago it is normal to find high readings on the outside of built in water tanks or other areas water accumulates, especially if they have not been drained when the boat was lifted out.
I now drain my water tanks whenever the boat is not in use for a while even if still afloat.

 

[Kukri]

I think that it is generally better to lay up a GRP hull ashore each winter.

 

[srm]

I think that it is generally better to lay up a GRP hull ashore each winter.

Probably, but a lot depends on the age/construction/resin used/subsequent coating.
My current boat spent one winter afloat in its first 15 years having had an epoxy primer from new.
When I bought her the hull was cleaned followed by three coats of high build epoxy and Coppercoat in spring 2009. Since then she has only been out of the water for two winters '15/16 and '19/20 when the Coppercoat was touched up in places.
Winters ashore were difficult to organise where I kept my boat and are a problem here without booking many months in advance.
No sign of any problems so far.

 

[skyflyer]

I think that it is generally better to lay up a GRP hull ashore each winter.

apart from last winter, it always has been

 

[srm]

I think that it is generally better to lay up a GRP hull ashore each winter.

On reflection I can think of a number of GRP hulled fishing and work boats that probably spent no more than one week a year on the slip but were otherwise earning a living all year round.

 

[lustyd]

If you employ a witch hunter, they will find you a witch.
I have yet to see a moisture related problem on a plastic boat. Sure, some have had cosmetic issues, all of which are repairable easily and cheaply. Ask the surveyor for specific and detailed information on how these readings will manifest themselves and what that will mean for you as an owner. Their supply of words will very likely run low at this point.

 

[Kukri]

There is or was said to be a thing called “going soft”, which happened to GRP hulls over time. It might have been folklore.

 

[sailaboutvic]

My last boat had only been out of the water for a couple of weeks in six years,
And 48 hours before the survey.
When survey for the new owner the moisture level where very low .

 

[AndrewB]

I also bought my boat 10 years ago after the surveyor 'condemned' it as having far too high moisture readings. But there was no sign of osmosis, two keel-bolts checked clean, and I was inclined to agree with the broker's aside that some surveyors are just trigger-happy with the meter. Though naturally I used the report to negotiate a sizeable discount on the asking price.

After studying the readings I realised that the nearer one was to a deck fitting, the worse it was. Sure enough, the main problem proved to be failed sealant around almost all the deck fittings. Presumably never touched since the boat was new. It took a bit of work to pick it all out and replace, but was not difficult. Then the yacht was stored ashore for four months. After this moisture levels were, and have remained, quite normal.

 

[Kukri]

Hong Kong ought to be ideal for osmosis; all boats are kept afloat year round in warm water, as there is nowhere to put a boat on shore. A yard will whistle your boat out of the water, do what needs doing in half no time, and chuck her back in in 24 or 48 hours.

 

[Seaway Channel]

Moisture readings are pointless. They are the equivalent of saying a 20 year old car may have body rust. Older boats in the water will always show moderate to high moisture readings, as will boats sat on a rainy quay in the winter…

 

[Refueler]

I also bought my boat 10 years ago after the surveyor 'condemned' it as having far too high moisture readings. But there was no sign of osmosis, two keel-bolts checked clean, and I was inclined to agree with the broker's aside that some surveyors are just trigger-happy with the meter. Though naturally I used the report to negotiate a sizeable discount on the asking price.

After studying the readings I realised that the nearer one was to a deck fitting, the worse it was. Sure enough, the main problem proved to be failed sealant around almost all the deck fittings. Presumably never touched since the boat was new. It took a bit of work to pick it all out and replace, but was not difficult. Then the yacht was stored ashore for four months. After this moisture levels were, and have remained, quite normal.

Deck fittings ? How many people have their decks / coamings metered ? I suggest that vast majority only have lower hull metered.
But what can happen there ... and this example is from a survey I conducted in Southampton :

Boat was on trailer ready to ship out. Meters were referenced, I have two, .... commenced checking hull. Generally low readings then high at particular narrow bands vertically.
Question to Owner - was there ever any water problem inside ? Answer was that years earlier - rain had entered and filled the bilge, overflowed the cabin sole.
The high readings I was getting was where the wood bulkheads butted the hull.
Owner was surprised at the precise nature of readings outlining those bulkheads exactly - particularly that he had used De-Humidifiers inside for long period to remove the moisture.
Checking inside boat - there was no indication of damp or what had happened.

Anyway .....
Its worth noting the differences of meters ......

The typical Sovereign meter brought out actually is not a deep penetrative meter as some claim ... while other meters can be seriously deep penetrating.
The Sovereign as often seen is actually quite limited in depth and sensitivity. But the Tramex Skipper is so sensitive - it will detect fittings inside hull that have different material.
This difference can make for poor reporting. The user MUST reference his readings ... must take into account factors to determine report.
I have two meters ... Protimeter - used on thin wall GRP ... Wood .... Ferro boats (yes checks on other material construction can be made). Tramex Skipper for thick GRP and for Osmosis treatment checking due to its extremely high sensitivity.

I suggest that the heyday of Osmosis Treatment had many boats subjected to expensive work that in reality could have been avoided.

I see people quoting "numbers" ..... which TBH are generally meaningless as a number here. Where is the reference number ?

 

[jwilson]

Hong Kong ought to be ideal for osmosis; all boats are kept afloat year round in warm water, as there is nowhere to put a boat on shore. A yard will whistle your boat out of the water, do what needs doing in half no time, and chuck her back in in 24 or 48 hours.

Yes - many older boats there have osmosis. If a cruising boat is ashore 48 hours in a year it must have needed major work. Otherwise out, clean, re-antifoul etc and in again in a half-day with half a dozen people at work.

 

[Elessar]

If you’re buying a 25 year old GRP boat, which has no evidence of osmosis, and was (according to PO) prophylactically epoxy coated below waterline when three years old, (receipts to prove it), then how concerned should you be about high moisture readings in certain areas at pre purchase survey. The surveyor is Saying it needs to be fixed, albeit not immediately, involving removing gelcoat (including some abovecwaterline).
Additional info. The outer layers of the entire hull laminate is constructed with vinylester not polyester resin as this is (supposedly?) 100% resistant to water penetration.

I wouldn’t be worried at all unless it was a cored hull. If it is and the surveyor didn’t mention that then that is a very special level of incompetence.

 

[hurley]

Can you use the survey to negotiate a discount in the sale price in the region of the amount of money it would cost to undertake the surveyors recommendation. Your rationale would be that if the vendor declines then he is likely to encounter the same issues with any other prospective sale and that you will either have this additional expense or incur a similar reduction from a purchaser later down the line in the event you don't undertake the work. The vendor may just want to take a bit of a hit just to move it on and be free of the emotional distress selling a boat can cause.

Similarly how intent are you on buying this vessel...could be worth taking a few deep breaths to evaluate the balance between you rational mind and emotional mind and go from there.

Good luck Bw

 

[Kukri]

Can you use the survey to negotiate a discount in the sale price in the region of the amount of money it would cost to undertake the surveyors recommendation. Your rationale would be that if the vendor declines then he is likely to encounter the same issues with any other prospective sale and that you will either have this additional expense or incur a similar reduction from a purchaser later down the line in the event you don't undertake the work. The vendor may just want to take a bit of a hit just to move it on and be free of the emotional distress selling a boat can cause.

Similarly how intent are you on buying this vessel...could be worth taking a few deep breaths to evaluate the balance between you rational mind and emotional mind and go from there.

Good luck Bw

I think that the cost of this work (for the sake of argument, £20K) is already reflected in the asking price - see post 2 above - for any older GRP boat.

Each of the possible hull materials has its own built in problems. Even bronze (yes, it’s been done).