Buying advice : Would you trust a 50yr old polyester boat?

[jorxster]

Hi all,

Here in New Zealand the second-hand market for yachts is pretty steep. I'm looking for a quality blue water cruiser and that naturally means $$$.
I was talking to my surveyor who said that polyester resin built hulls are not water tight and eventually saturate with water, and that this applies to all yachts built before 1989, when it seems epoxy or vinyl-ester resins started to be in use. What are your thoughts on this?

Because occasionally I see a yacht that looks great, seems to be built well, but is quite old, (1975 in one case, a Bowman 57 built in the UK.). Almost 50 years old! Which I find astonishing, but everything about this boat seems to indicate quality. Wouldn't it be crazy to consider a 50yr old boat built before the times of epoxy resin, or is my surveyor overly cautious?

What's the worst that could happen? Do fiberglass hulls (of polyester resin) eventually just saturate with water, and is there nothing that can be done about that?

cheers, it's my first time seriously looking for a yacht.
Jordan

[coopec43]

Compared to the modern F/G yacht they would be a lot more heavily built.

Why not give the below the waterline part of the hull a barrier coat?

https://www.sailnet.com/threads/is-a...ts-life.57549/

I don't know if this video would be any help?

https://www.youtube.com/results?sear...berglass+hulls

[Joli]

There are a lot of old boats out there. We sail a fifty year old balsa core boat. It's best to hire the best surveyor you can find. There will be problems due to age but there are problems with new boats too.

[HankOnthewater]

Hi Jordan, there are a lot of GRP boats that are 40 or 50 years old. and indeed some hulls may have absorbed a little water along the way.
I have one of those boats. Am I worried....? No I am not.

And vinyl ester resins, yes they are better barrier for water, but how much of this kind of resin was used in each boat? There is hardly a way (that I know) that can tell. And if if the brochure says "vinyl ester"..... was it one layer? all layers?

[jorxster]

Thanks @HankOnthewater, why are you not worried? Pardon me, I'm pretty ignorant but I have watched a few videos on the topic.

I've got a pretty good surveyor here, though like originally mentioned, he's wary of boats pre-1989.

I hadn't heard about barrier coats, that almost sounds too easy!

[boatpoker]

Originally Posted by jorxster

Hi all,

Here in New Zealand the second-hand market for yachts is pretty steep. I'm looking for a quality blue water cruiser and that naturally means $$$.
I was talking to my surveyor who said that polyester resin built hulls are not water tight and eventually saturate with water, and that this applies to all yachts built before 1989, when it seems epoxy or vinyl-ester resins started to be in use. What are your thoughts on this?

Because occasionally I see a yacht that looks great, seems to be built well, but is quite old, (1975 in one case, a Bowman 57 built in the UK.). Almost 50 years old! Which I find astonishing, but everything about this boat seems to indicate quality. Wouldn't it be crazy to consider a 50yr old boat built before the times of epoxy resin, or is my surveyor overly cautious?

What's the worst that could happen? Do fiberglass hulls (of polyester resin) eventually just saturate with water, and is there nothing that can be done about that?

cheers, it's my first time seriously looking for a yacht.
Jordan

Polyester resin is not waterproof but there is more to it than that.
The saturation point of polyester is about 1.5 to 2%, thats not very much. It is bad on some boats and makes no difference to many.
I've surveyed many 50yr old boats that were still sound.

Some more info here ...
Moisture Meter Mythology and Flir thermal imager

[HankOnthewater]

Originally Posted by jorxster

Thanks @HankOnthewater, why are you not worried? Pardon me, I'm pretty ignorant but I have watched a few videos on the topic.

I've got a pretty good surveyor here, though like originally mentioned, he's wary of boats pre-1989.

I hadn't heard about barrier coats, that almost sounds too easy!

I am not a fibreglass expert like some here on the cruisers forum, although I have built a few small boats in fibreglass and repaired many others. People like the previous poster (boatpoker) and others have seen more boats than I have.

OK, my take......fibreglass (resin) is not 100% waterproof. Vinylester is a lot better (ie more waterproof) than the other 2 types of resins (orthophthalic and isophthalic), but one layer vinyl ester (the outer) only gives marginal protection. I would think one needs more than one layer of vinylester to gives such protection, and then.... there are many dozens of different vinyl esters, some are better than others.

A well built GRP boat by a reputable people or yard, should not have any issues, whether before or after 1989 (the year your surveyor mentioned).

If a boat has some water in it (oops, I should say "has high moisture content), within the layers..... some people put an epoxy barrier coat on it. I always wonder about such move. It just seals the water that is present already into the boat. I would say that the gelcoat needs to be removed and the boat to be on the hard in a warm dry climate for many months, or much longer than that, to get rid of the water. When the hull is dry, then sealing makes sense, and in fact is needed. And more often than not, epoxy resin is then used as this is the most waterproof barrier

And about being worried, read the link of boatpoker about myths and facts on moisture.

I am not worried about my boat as it was built by a reputable yard, that as far as I know, never had a hull problem.

[Sailorman97]

Originally Posted by jorxster

Hi all,

Here in New Zealand the second-hand market for yachts is pretty steep. I'm looking for a quality blue water cruiser and that naturally means $$$.
I was talking to my surveyor who said that polyester resin built hulls are not water tight and eventually saturate with water, and that this applies to all yachts built before 1989, when it seems epoxy or vinyl-ester resins started to be in use. What are your thoughts on this?

Because occasionally I see a yacht that looks great, seems to be built well, but is quite old, (1975 in one case, a Bowman 57 built in the UK.). Almost 50 years old! Which I find astonishing, but everything about this boat seems to indicate quality. Wouldn't it be crazy to consider a 50yr old boat built before the times of epoxy resin, or is my surveyor overly cautious?

What's the worst that could happen? Do fiberglass hulls (of polyester resin) eventually just saturate with water, and is there nothing that can be done about that?

cheers, it's my first time seriously looking for a yacht.
Jordan

Survey the bottom. Do moisture meter readings. I have seen a hull that read 30 on a moisture meter. It was peeled and then sanded ( peeling is very hot and seals the hull) . After it was sanded it still measured 30. The boat was then pressure washed with hot water 210° every day for 30 days. The moisture levels came down to 4%. It was given 12 coats of Interprotect and 10 yrs later it still measures 4%.

Nothing wrong with older hulls as long as they are solid.

[sailingunity]

My boat is 48 years old. Previous owner stripped the bottom to glass and put barrier coat on - we have had no issues and the survey was sound when we bought it.

I have heard similar comments to boatpoker from other owners - it might be a wet hull, but doesn't make it inherently unsafe.

[bil56]

a boat doesnt sink by osmosis, but troubles will ensue: less rigidity of the rig, and mainly softening and damage to the bottom in the event of impact (grounding)

[boatpoker]

Originally Posted by bil56

a boat doesnt sink by osmosis, but troubles will ensue: less rigidity of the rig, and mainly softening and damage to the bottom in the event of impact (grounding)

So many people have different definitions of osmosis that I never know what they actually mean. What do you mean by osmosis ?

Do you mean gelcoat blisters, skinout blisters, intralaminate blisters, hydrolysis ?

[wingssail]

Originally Posted by jorxster

Hi all,

Here in New Zealand the second-hand market for yachts is pretty steep. I'm looking for a quality blue water cruiser and that naturally means $$$.
I was talking to my surveyor who said that polyester resin built hulls are not water tight and eventually saturate with water, and that this applies to all yachts built before 1989, when it seems epoxy or vinyl-ester resins started to be in use. What are your thoughts on this?

Because occasionally I see a yacht that looks great, seems to be built well, but is quite old, (1975 in one case, a Bowman 57 built in the UK.). Almost 50 years old! Which I find astonishing, but everything about this boat seems to indicate quality. Wouldn't it be crazy to consider a 50yr old boat built before the times of epoxy resin, or is my surveyor overly cautious?

What's the worst that could happen? Do fiberglass hulls (of polyester resin) eventually just saturate with water, and is there nothing that can be done about that?

cheers, it's my first time seriously looking for a yacht.
Jordan

I do trust my 50 year old yacht. Honestly, it never dawned on me that my hull could be saturated! (that shows how ignorant I am). And our boat was not built by a reputable builder (more like some rednecks in a barn in New Orleans).

But our hull surveys fine, though we've never had a moisture meter on it. It is still stiff: we can put 4000lbs on the backstay (hydraulic) and not have any obvious deflection or slackening of the rig. When we've worked on the hull we've not found any moisture.

So maybe it's OK.

Would I buy a 50 year old fiberglass boat? Should you? Get a good survery and not one from a guy who is prejudiced against it before he starts. And watch the process closely. He (you) will find problems. It's an old boat. But decide based on what you find.

[Manateeman]

Before the term fiberglass came into Boatbuilding language it was called silver glass. There are some hulls that were hand laid up which will stand any test.
The key is the glass to resin ratio.
When we cut a hole, we weighed the cookie, burned it till it was just glass and weighed it again.
The chopper gun really lowered the strength. Horror of horrors...balsa.
Who built the hull and core test results if available. That will tell you a lot.
The manatee crew.

[boatpoker]

Originally Posted by jorxster

I was talking to my surveyor who said that polyester resin built hulls are not water tight and eventually saturate with water, and that this applies to all yachts built before 1989, when it seems epoxy or vinyl-ester resins started to be in use. What are your thoughts on this?

The vast majority of hulls built today are polyester, some with vinylester gelcoat and a few with vinylester gelcoat and skinout mat . Few are built solely with epoxy or vinylester.

[Sailor Sailor]

Originally Posted by jorxster

I was talking to my surveyor who said that polyester resin built hulls are not water tight and eventually saturate with water, and that this applies to all yachts built before 1989, when it seems epoxy or vinyl-ester resins started to be in use. What are your thoughts on this?

"What are your thoughts on this?"

It is not believable; it does not sound possible. No one is that stupid.