old vs new fiberglass sailboats hulls

[kafka]

when do you consider a fiberglass hull to be too old? if you were buying a boat, would you even look at ones built in the 60's, especially early 60's?

I claim ignorance on this matter and am interestred to hear what others thing. I ask this for a couple of reasons. I read an article recently that talked about how older sailboats have a lot of glass (very thick hulls) but newer boats are stronger even with less glass. So- when was that transition period between the thick hulls to what I assume we have today, thin efficient hulls? was there an era of sailboat building where they really did not have it correct and under built the hulls thinking they were stronger than they were? Or- is this boat builder specific and hull thicknees not seen as a trend throughout the industry?

interested to hear your thoughts.

[johnar]

From what i have read boats built right after 1973 or 74 are the ones that had the blister problem, I am not sure about the boats made in early 60's.

John

[w42]

With fiberglass construction being new in the 60s, FRP boats were mostly built by those who had wooden boat building experience. There was no data, modern glass and resin materials that you have today. It was mostly guesswork. Hulls were thick from doubling/tripling the "guessed" amount of material because no one knew how it would perform.

The transition to more "modern" FRP boats probably started in the late 80s early 90s as more modern weaves of glass and stronger core materials were developed. Things are still changing with the advent of vacuum RTM and prepreg layup methods.

When considering boats built in the 60s, I would look at the builder, how many boats they built, how many are still on the water and what condition they are in. If it is a one-off construction by some unknown builder, it is a crapshoot. In which case you really need to look (or have an experienced someone) look closely at the hull and structure and how it was constructed. Finding a surveyor who really knows FRP boat construction history is tough. Not any old surveyor is qualified.

[anotherT34C]

With fiberglass construction being new in the 60s, FRP boats were mostly built by those who had wooden boat building experience. There was no data, modern glass and resin materials that you have today. It was mostly guesswork. Hulls were thick from doubling/tripling the "guessed" amount of material because no one knew how it would perform.

I've heard this lots, but never from an actual engineer of the era. Knowing what I do about engineering, I find this a tough line to swallow.

Flexing is pretty damaging to fiberglass, and if I had to make a guess, I'd guess that the thicker hulls of previous decades had more to do with combating flexing, while newer formulae are more resistant. Of course, I don't really know... just a guess. I just find it difficult to believe that engineers of the 60's didn't know exactly how strong their hulls were.

[w42]

Originally Posted by anotherT34C

I've heard this lots, but never from an actual engineer of the era. Knowing what I do about engineering, I find this a tough line to swallow.

Flexing is pretty damaging to fiberglass, and if I had to make a guess, I'd guess that the thicker hulls of previous decades had more to do with combating flexing, while newer formulae are more resistant. Of course, I don't really know... just a guess. I just find it difficult to believe that engineers of the 60's didn't know exactly how strong their hulls were.

That is part of the problem with evaluating these boats. Many of those boats were not "engineered" from the ground up with the new material. Pleasure boat design and construction in the 60s was not as rigorous like that of aerospace of the same time, the budgets (and liability) were simply not that big. Much if it was "rule of thumb" or scantlings adapted from other materials construction (i.e. wood).

This uncertainty caused many builders, not necessarily the designers, to double and triple quantities.

As you say, you are just guessing. If you really want the straight scoop on this, give someone like Bob Perry a call. He's been doing this since the early 70's and I am sure has plenty of stories/data.

If you find this hard to swallow, consider running away from the boat .

[dcstrng]

Originally Posted by kafka

if you were buying a boat, would you even look at ones built in the 60's...

I would certainly look at vessels of the 1960s, but not blindly… any more than I’d ignore the issue on a vessel of recent vintage… there were boats decidedly over-built in that era (as now…), as well as semi-disposable boats designed for the mass-market with only minimal thought for longevity… Boats of the earlier era were nearly devoid of the stringer systems we see today, depending upon a few bulkheads and (usually) heavy hull thickness for rigidity… the next evolution seems to be the hull-liner, and on the better boats although occasionally hideous, the liner was a structural member… however, on others, the liner simply floated inside the hull, strategically bonded, but not contributing as much as modern liners fully bonded… As others have said, the history of the manufacturer is a good place to start (not whether they are still in business – the luxury tax of late-80s/early-90s decimated the industry and many never returned – but the reputation of the hulls in service… Hinckley versus Bayliner sort of comparisons).

Opinions vary with the shifting of the winds, but I’ve seen blisters in almost all years of boats, although there was a period from the mid-1970s where many manufacturers ran into very serious problems where resin/glass ratios weren’t optimum before the science of composite construction became fully developed… I’m inferring from your question you are looking at how well an older boat may have weathered the years…? Given that earlier glass hulls are pretty low-tech compared to modern exotics, they are fairly easy to repair at least back to original structural standards – especially using modern DIY materials. Whether that is economically feasible depends a lot on the repair/maintenance required and the participation of the skipper… I did a repair on a void in my keel last spring that required only about $75 worth of epoxy and associated material, but if I’d had to engage the yard the repair probably would have exceeded the dollar value (which doesn’t always reflect the emotional value) of the boat… looked like it had been damaged from some impact, and just as she was going back in the water we noticed another on the very bottom of the keel – but that’s a matter for this years haul out…

Bottom line is, for the types of boats I tend to look at – early is just fine; lower tech, but generally easy to repair with few hidden areas that can’t be gotten to; however, the years affect all boats so as always, the level of maintenance will usually be the finally factor regardless of the original manufacture’s prowess…

[Talbot]

60's boats are likely to be better than early 70s. Early boats were built with the best resins, that became too expensive following the oil crisis in abt 74. for a few years after that, a lot of the boats started to develop osmosis problems that lasted well into the 80's (and later with some)

[kafka]

Originally Posted by dcst rng

I’m inferring from your question you are looking at how well an older boat may have weathered the years…?

this is exactly what im inferring...right on. More to the point- im looking for a blue water cruiser, and was wondering if there were time periods best to avoid for hull reasons (strenght, longevity, ect) or if it is based more on the manufacturer.

any manufactures that have reputations for having build consistently good hulls?

[Pblais]

More to the point- I'm looking for a blue water cruiser, and was wondering if there were time periods best to avoid for hull reasons (strength, longevity, ect) or if it is based more on the manufacturer.

Age of hull, is perhaps less important than age of gear attached. Replacement of all the items screwed, bolted and otherwise attached exceeds the value of the hull many times over. A 1960's original electrical system is at best worthless and at worst outright dangerous. The 1970's isn't much better nor much of the early 1980's.

If you look at the traditional blue water boats they are vendors that consistently built good hulls. It's part of what makes them the blue water boats with a track record.

During the period of the oil crisis of Jimmy Carter years resin prices skyrocketed and some suppliers sold cheaper poor quality resin at lower prices mostly because that was what it was worth. Many people not knowing thought resin is resin so bought a lot of cheap stuff given boat taxes were high and the boat business was hurting bad. There were known ranges of hulls that feel in this group. None of them today would show without apparent problems. Many have been repaired and so some may be in better condition than others.

I wouldn't consider boats older than late 1970's. The rest of the problems that come with a boat that old are far worse then most of the hulls a great deal older.

[Ex-Calif]

Originally Posted by Talbot

60's boats are likely to be better than early 70s. Early boats were built with the best resins, that became too expensive following the oil crisis in abt 74. for a few years after that, a lot of the boats started to develop osmosis problems that lasted well into the 80's (and later with some)

I have heard this and tend to agree about the oil crisis boats.

If a boat from the 60's is still floating and showing no blisters I would go for it witout reservation. Unfortunately, unless there has been a lot of work on the boat the deck gear is likely to be less modern.

The biggest drawback is the interiors. I am a lazy fart and just would rather sail than take care of wood. Plastic interiors may not look "traditional" and you love them or hate them but they are easy to take care of.

However my wife is early 60's vintage and while I certainly do notice later vintages I wouldn't trade her out just because of age Her fiberglass bits seem to be holding up OK...

[nautical62]

I owned a 1969 boat until about five years ago, and personally I'd buy that same boat again. The hull was thick and solid with no signs of upcoming problems that I could detect. However, I agree, that one needs to be careful with any kind of stereotyping or generalities. I'm sure there are some 60s models that will be around for decades to come and others that are at the end of their life.

I think Paul made a very good point about not focusing too much on the hull. The rest of the boat can and will age as well which can not only be expensive, but dangerious if you don't notice discover a potential failure in time.