Fiber glass life span

[MOP]

I was thinking about older boats and wondering just how long they will really last, I found an interesting read that may many of us think about buying new! If I read it right it looks as if an older boat is a better bet then newer ones, the old phrase they just don't build them like they use to may have more meaning then we thing!

Phil

http://www.boatdesign.net/forums/showthread.php?t=11455&page=2

[gcarter]

Of course there's a lot of different facets to consider....
The first large commercial undertaking of glass boats was a 40' +/- sloop that went into production in '47, I think. I saw an excellent example of this model in about 72 (I think), so it was already about 25 years old. I wonder if any are still around?????
The first piece of 'glass Chris Craft put into production was the tail fin on the Scorpion (????) in about '54. Obviously the perfect place for an organization that was timid/reluctant to switch horses, it was a low production boat and the piece was non structural. But all the ones I've seen seem to be original pieces.
Then there's the old bugaboo of osmotic blisters.......
It seems the early 'glass FBSF ('60's) were almost immune to this phenomina compared to boats built since the '70's and currently. That problem seems to have been a resin change that took place in the chemical industry and not necessarily the by the boat builders. However, using vynalester resin in the outer layup seems to help, but of course it costs more. Probably the best solution is after buying the new boat, have an epoxy barrier coat applied to the bottom before applying bottom paint the first time.

I like older FBSF's a lot. They're comfortable, roomy, have good viewing from the slightly elevated salon, a very useable low cockpit, and of course everyone loves riding in the fly bridge. I've often thought if I were in the market again for one of these boats again I'd probably buy an older one and restore and repower it. I believe it would simply be a better boat.

[Carl C]

I've got to think that weight is a factor. The boats discussed in the link are not performance boats and are probably considerably heavier than their modern counterparts. Also, I wonder why welded aluminum construction isn't more widely used.:boat:

[Tom Davis]

Without getting into a whole lot of detail here are my thoughts.

Look at boats made in the 50's and 60's, designers and builders had no idea how thick the glass needed to be to support the stresses involved for large sail boats so they just made a very educated guess and doubled it. If you look at a 1965 Irwin 46' sloop there are places on the hull that are 3" thick solid fiberglass! Check out the early MFG (Molded Fiber Glass) power boats and the hull thicknes! Then they realised how strong it really was and saved a pant load of money over the years making it thinner and thinner and the boats still held together for the most part.

The second change is in the chemical make up of the resin, thanks to countless environmental impact studies allot of the chemicals used in earlier resins and bottom paint are now illegal (Except for the US Navy) to be used and are no longer available to the general public. The old really toxic stuff worked much better! Just try adding a few teaspoons of tributal tin to your bottom paint... but thats a whole different story.

So the bottom line is: cost of materials and labor as well as environmental impact have made older boats much stronger than newer boats. But keep in mind that even the strongest properly sealed fiberglass will degrade over time due to stress and oxidation. So a boat built in 1965 is still 42 years old compared to a new boat, it's got a pretty good head start.

Just my .02

Tom Davis
Winni Bandits

[Formula Jr]

I believe you are thinking about the '55 CC Cobra there Big G.


I'm a bit of a contrarian when it comes to Fiberglass and how long people think it lasts. Plastic reinforced glass fibers are like a clock.

There are industrial design museums all over the world that are losing their plastics collections because the items are just starting to melt down and fall apart. No one really knows why. These are sixty year old items. That have been protected from UV.

The "forever" aspect of PRG products has been over sold.

When you make a fiberglas boat, it is on a time line, or what people would call a bell curve as to structural integrity. For the first 20 years it will get stronger. Then it will max out, and then it will get brittle. Its the pastic part that fails cause we know spun glass lasts a very long time.

I seen 30 year old boats where I could kick panels in, just because they had completely off gased and the plastic had lost its long molecular chains. Its just glass and mechanically bound powder then. And no way to fix it or patch it cause the whole boat was like that.

If you can't still smell the off gassing of a glass boat, its on its way to being brittle.

While at last years seattle boat show, I got into a little rap about the genmar roto moulded thermal pastic boats. I got a little lost in the sales pitch to my wife cause I love the whole "green" idea of them.

A crowd had gathered. There were like 12 people standing and listening. It was fun...

[gcarter]

This is a pretty interesgting thread.
One way to approach this is to look at all alternatives and the practicality of them.
Carl mentioned welded aluminum. It's good if constructed properly....corrosion is a bitch. Also metal boats don't scale down very well...particularly steel boats.
Conventional wooden boats do pretty well in the far North where you don't have such "critter" problems. Although it seems I've read there have been three or four "Blur Nose" scoonerfs built, so I guess cold water isn't the only thing necessary for the longevity of wood boats.
I once read a disertation on various boat building materials. The central argument was a comparison of the relative qualities of paint stir stick sized samples. Among the samples were wood (spruce), fiberglass, steel, aluminum, and wood saturated with epoxy (more later). The strongest compared to weight was the strip of spruce. The main problem of wood boats is it's made of pieces nailed or glued together. It always moves in the joints and comes apart. Fiberglass is VERY heavy and will break before the strip of spruce. Steel and aluminum will not recover and stay bent. In summary the WEST system of many small strips of wood epoxied together on a male mold is VERY good. It's very expensive as there's no easy way to mass produce it. And to make it even better it needs to be baked in an autoclave. But it would ALWAYS need to be painted because the epoxy has poor resistance to UV. The other thing is we have even less knowledge of it's longevity.
But I would love to have a 25' stepped hull made of it.:eek!::eek!: