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

[Cheechako]

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 would focus on the boat itself. Even if vinylester or epoxy STARTED in 89, my sense is few were built that way for quite a while. The down side to later boats is more of them were cored hulls.
I have seen badly blistered boats and boats with no blisters after decades. It's difficult to say really. I would tend to buy in the 80's or later as the 70's were a lot more hit and miss in the learning curve of plastic boats.
Sure, modern material might be a plus, but it sure narrows your search on a budget.

[jorxster]

I want to thank you all for your replies, there's a wealth of knowledge here! Carefully reading every link. Thank you. I'll admit, my paraphrase of my surveyor does seem a bit oversimplified, but that's probably my limited understanding of the conversation I had with him.

[Don C L]

My 60 year old hand laid up, no core hull is doing fine. Pretty sure it will outlive me.

[coopec43]

Originally Posted by Cheechako

I would focus on the boat itself. Even if vinylester or epoxy STARTED in 89, my sense is few were built that way for quite a while. The down side to later boats is more of them were cored hulls.
I have seen badly blistered boats and boats with no blisters after decades. It's difficult to say really. I would tend to buy in the 80's or later as the 70's were a lot more hit and miss in the learning curve of plastic boats.
Sure, modern material might be a plus, but it sure narrows your search on a budget.

Uhmm! I take objection to your statement "The down side to later boats is more of them were cored hulls" because my yacht has a cored hull and deck!

What is wrong with cored hull and decks? That is the way most quality yachts are built - Hallberg Rassy, Amel, Contest, Kraken, Hylas 46, Tartan 3700.....

[Ballsnall]

Originally Posted by coopec43

What is wrong with cored hull and decks? That is the way most quality yachts are built - Hallberg Rassy, Amel, Contest, Kraken, Hylas 46, Tartan 3700.....

When looking at older boats it's the core that is most important rather than what resin used. If the core is gone then the boat is scrap, he wasn't implying there was anything wrong with it as a construction method.

[rslifkin]

Originally Posted by coopec43

Uhmm! I take objection to your statement "The down side to later boats is more of them were cored hulls" because my yacht has a cored hull and deck!

What is wrong with cored hull and decks? That is the way most quality yachts are built - Hallberg Rassy, Amel, Contest, Kraken, Hylas 46, Tartan 3700.....

Cored decks are almost universal. Cored hulls less so. But any cored structure has more ways things can go wrong over time (especially if it wasn't built or worked on perfectly), so there are more concerns and things to check for. Not to say a cored hull is bad, just that they need extra attention to be sure of condition.

[coopec43]

This article by a Marine Surveyor "Cored Vs Solid" hulls/decks is pertinent and highly relevant to the discussion.

https://themarinesurveyors.com/cored-vs-solid/

[coopec43]

Originally Posted by rslifkin

Cored decks are almost universal. Cored hulls less so. But any cored structure has more ways things can go wrong over time (especially if it wasn't built or worked on perfectly), so there are more concerns and things to check for. Not to say a cored hull is bad, just that they need extra attention to be sure of condition.

I'm surprised yo say that because I thought most production yachts would have cored hulls these days.

https://www.yachtworld.com/research/...22-and-beyond/

[nuku34]

To the OP:
I'm located in Nelson N.Z. My current yacht (my 4th in 45 years) is an NZ designed and built (1974) Cavalier 32 (10m sloop). There are many of these yachts still sailing in NZ. They were all built with some type of polyester resin (epoxy was too expensive at that time to use in the hull layup, but was used to glue hull and deck together).
Here are the construction details:
Hull: Balsa core GRP, Decks: Balsa core GRPConstruction: The Cavalier 32 was one of the early pioneers of cored fiberglass construction. The hull is built incredibly strong with hand-laid GRP and end-grain balsa coring.The layup from the exterior moving inwards starts with the gel coat which is reinforced by 1oz mat, then followed by 10oz cloth and two layers of 2oz mat. The balsa coring is 19mm thick in the bilge and 13mm thick above the waterline. Then comes 2oz mat and 24oz woven roving which forms a strong impact resistant layer.The deck/cabin has the same layup as the topsides. All through-deck fittings are backed by glassed-over wood. The hull-deck join is epoxy glued, then pop riveted with monel rivets every 6 inches and stainless steel bolts every 12 inches. The join is glassed over forming an interior gusset equal to the hull thickness.

The 2nd owner of Betelgeuse 2 hauled her in New Plymouth and she sat in his backyard for many months while he got her ready for an extended tropical cruise.
She did not have blisters (a type of osmosis), but he decided to have the below-the-waterline area gel-coat professionally stripped, and the entire area was given 2 coats of straight epoxy resin (not just a painted "barrier coat").



She's now 48 years old. Do I trust her. Absolutely. Cavalier 32's have circumnavigated. One survived multiple 360 degree rolls in conditions that sank a 65ft commercial fishing boat. She's way stronger than many modern yachts, she's a way better sailer, and more sea-kindly than any of the big interior volume, floating condo, plumb bow, flat bottom, wide ass "modern" yachts around.
That Bowman 57 you are looking at is a very good design and a quality build. Assuming she's been well looked after (even quality boats get trashed by lack of maintenance), she would look after you.


Question: do you really need a 57 footer? That's a LOT of boat and that's a LOT of $ per year for maintenance, berthing, insurance, etc. The buying price is just the beginning of yacht ownership.



The only draw back to buying a well-designed, high-quality, well-maintained, older yacht is you may have trouble getting full insurance. Many insurers in NZ will not insure a boat older than 40 years. You can get liability, but not hull/rig insurance. I am insured with the only NZ company I could find that will insure quality yachts over 40 years old, and that's because I got "grandfathered" in because the previous 2 owners used the same company.

[boatpoker]

Wet Balsa Core in Boats

[rslifkin]

Originally Posted by coopec43

I'm surprised yo say that because I thought most production yachts would have cored hulls these days.

https://www.yachtworld.com/research/...22-and-beyond/

Many do, but certainly not all. And many hulls are only cored above the waterline, a smaller portion are fully cored. It all depends on how concerned the designer is with weight in that specific model. In general, sailboats and fast powerboats are more likely to be cored. Slow trawlers, etc. are more likely to be solid glass hulls with cored decks, as the simpler construction and durability are preferred there and weight is a smaller concern.



Some builders make interesting choices. Like the Beneteau Swift Trawlers, which are fully cored from what I can find. But many of the newer Beneteau sailboats are (depending on model) either a solid glass hull (with cored deck) or only cored above the waterline.

[Joli]

Earlier this year in Antigua we had a Bowman 57 and a Swan 65 next to us. Both boats were immaculate and passaged regularly. I would trust both offshore in foul weather.

[coopec43]

Originally Posted by rslifkin

Many do, but certainly not all. And many hulls are only cored above the waterline, a smaller portion are fully cored. It all depends on how concerned the designer is with weight in that specific model. In general, sailboats and fast powerboats are more likely to be cored. Slow trawlers, etc. are more likely to be solid glass hulls with cored decks, as the simpler construction and durability are preferred there and weight is a smaller concern.

Some builders make interesting choices. Like the Beneteau Swift Trawlers, which are fully cored from what I can find. But many of the newer Beneteau sailboats are (depending on model) either a solid glass hull (with cored deck) or only cored above the waterline.

It wouldn't make sense to core the hull below the waterline on a yacht. Imagine tonnes of lead ballast being held in place by a cored hull? Or a fin keel attached to a cored hull?


BENETEAU 40 HULL GRID NEAR KEEL BOLTS (LOOKING FORWARD)

I am not familiar with the Beneteau Swift Trawler but I notice it is cored below the water line but still has a frame for stiffness. " The hull of the Swift Trawler 34 is fashioned from fibreglass around a balsa core, with a structural liner for stiffness...

I would want the motor and fuel tanks of a Beneteau Swift to be attached to solid glass at least.

[GILow]

As the happy owner of two solid fibreglass boats in their mid 40s I can say the surveyor was either misunderstood or misguided.

There’s no hard and fast rules, but one of the joys of buying boats of this age is you have a pretty good idea of what to expect. Neither of my two had reputations for hull problems and neither have disappointed me.

Both had barrier coats applied about twenty years ago, maybe that’s their secret to success. But I’m not laying awake worrying at night, partly because they’ve been fine until now and partly because they are both so overbuilt to begin with (as so many boats of their era were) that half the hull could fall off and you wouldn’t notice.

[Oeanda]

Agreed. The hull is the truest part of our 1980 boat. Narry an issue to report and it’ll probably be around long after I’m gone.

Admittedly I never thought of it as being a ‘polyester’ hull, and plan on disremembering that particular description…