How long should a modern GRP hull lasts as compared to one made 10 years
ago?

And how old is considered too old when taking a boat offshore into potential
rough conditions?

--
Adrian Smith

Adrian Smith wrote:

How long should a modern GRP hull lasts as compared to one made 10 years
ago?

And how old is considered too old when taking a boat offshore into
potential rough conditions?


Nic 32s were first made more than 40 years ago and are still making
trans-oceanic voyages. They were designed using scantlings scaled for
timber construction, and the assumption was that if it looked a bit skinny
it was better to beef it up a bit. Of course, a modern hull is very
different.

I would suggest the question should not be how it lasts, but how well it has
been designed and built.

I would be very happy to take some modern boats round the world (if I wanted
to, which I don't). Others I would be unhappy taking out of harbour if the
weather looked nasty.

"Adrian Smith" wrote in message
...
How long should a modern GRP hull lasts as compared to one made 10 years
ago?
And how old is considered too old when taking a boat offshore into
potential rough conditions?
Adrian Smith

There are so many variables, I would think it's virtually impossible to give
a definitive answer.
A well laid up GRP hull should last indefinately, provided it's looked
after. GRP lay-ups vary wildly from make to make and generally speaking,
older offshore boats have thicker hulls utilising low tech materials, many
of which I suspect will outlive more modern lighter build, high tech ones.
In fact, a good
10-20 year old Hallberg Rassey, Contest, Rival, Westerly, Moody etc. may
have a few blisters but will still be stronger than many brand new popular
EU production line boats are today. Having said that, they probably won't
sail as quickly but I know which one I would rather rely on in rough
conditions.
There is no "age" limit for an offshore boat, it depends more on the
build quality, suitability of design and whether the necessary maintenance
and replacement of fittings, rig, etc. has been carried out properly over
the years.
Graham.

Graham Frankland wrote:

a good 10-20 year old Hallberg Rassey, Contest, Rival, Westerly, Moody etc. may
have a few blisters but will still be stronger than many brand new popular
EU production line boats are today.

Oh no, here we go again :-)
Nobody mention the 'B' word...

Adrian Smith wrote:
How long should a modern GRP hull lasts as compared to one made 10 years
ago?


The material, design, type & execution of the lay-up will
matter a lot more than whether it popped out of the mold
last week or 10 years ago.

About the only maintenance issue is if it's cored, then the
skins must stay bonded to the core and no water should be
allowed in (ie deck fittings properly thru bolted & bedded).

If you're talking *only* about the structural integrity of a
fiberglass hull & deck, it should last forever within a
certain range of stress. The more strongly it's built, the
wider range of stress it can take. Once it is loaded /
stressed enough to break a few of the bonds within the
lamination, it is said to be "fatigued" just like metal that
gets bent back & forth. Fiberglass has some advantages over
metal in that it can bend further without fatigue, and can
accumulate a higher number of fatigue cycles, but that
number is not infinite. Another good thing about fiberglass
is that it's relatively easy to re-bond bulkheads & other
structural members inside.



And how old is considered too old when taking a boat offshore into potential
rough conditions?


The old-fogey brigade will insist that older is better, for
a number of reasons. Old fashioned hull & rigs can be more
seakindly (altho old running rigging & deck fittings can be
awful to cope with). Some will even claim that 'back in the
old days' the boat builders did not know how strong
fiberglass was, so they made it incredibly thick & strong.
The fact is that engineering data was available on
fiberglass from the early 1950s on, readily available to
those who cared to look... is ignorance a good excuse?
Another fact is that resin/fiber ratios in many older hulls
is poor.

It's more of an issue about the functioning of all
systems... rig, plumbing, electrical, electronic (if any)
than the age of the hull.

Hope this clears some things up.

Fresh Breezes- Doug King

"peter" wrote in message
ups.com...
Graham Frankland wrote:

a good 10-20 year old Hallberg Rassey, Contest, Rival, Westerly, Moody
etc. may
have a few blisters but will still be stronger than many brand new
popular
EU production line boats are today.

Oh no, here we go again :-)
Nobody mention the 'B' word...


Are we saying that modern EU production line boats are not as strong as the
ones made in 'the good old days' when things was done proper:-)

I'm new here, but if the 'B' word is Beneteau. How strong and what is the
durability of their hulls?

--
Adrian Smith

I'm new here, but if the 'B' word is Beneteau. How strong and what is the
durability of their hulls?

--

Perhaps once upon a time it referred to Beneteau, but there's a new bad boy
on the block..... :-)

Commodore Joe Redcloud© wrote:
The reason early fiberglass boats were built on the heavy side was not
because builders didn't know how strong it was. That may have been a
factor for a few, as not all boat builders are on the cutting edge of
technologhy at all times.

The real issue was that builders needed to convince non-technical boat
buyers and traditionalists that fiberglass was as good or better than
wood. If the material looked too skimpy, it made nervous buyers think
"cheap and flimsy". Even today, wood boat fans derisively refer to
fiberglass boats as "clorox bottles.

It is mostly a preception and marketing issue, not an engineering
issue.


Commodore Joe Redcloud©

I get that irrational fear that the boat is not as strong as it should
be every time I am rummaging around in the cockpit locker and see
daylight through the hull. Maybe builders of modern boats should
include a layer of opaque resin?

Nick

GRP lay-ups vary wildly from make to make and generally speaking,
older offshore boats have thicker hulls utilising low tech materials, many
of which I suspect will outlive more modern lighter build, high tech ones.

I was interested to see the wreck of a Joint Services Victoria 34 (Ensis) in
Cherbourg last year. I own one of the Halcyon 27s that were replaced by the
Victorias in 1990.

I was amazed how thick our Halcyon's hull is when I had to cut into it once.
The topsides are half an inch thick and it gets progressively thicker as you
go down; when I installed the log I was cutting through well over an inch of
dense GRP.

Ensis on the other hand had a sizeable hole and she wasn't half as think at
any point, the thickness also seemed to be uniform. Much more what I would
have expected actually.

David

"peter" wrote in message
oups.com...
Adrian Smith wrote:

Are we saying that modern EU production line boats are not as strong as
the
ones made in 'the good old days' when things was done proper:-)

Yes, and no. Some say that a heavily laid-up boat must be intrinsically
stronger and more seaworthy than a lightweight boat. Others argue that
if a lightweight boat has adequate strength in the necessary areas then
materials saving in areas where strength is not required is not a
problem.

I'm new here, but if the 'B' word is Beneteau

No, another B.


What manufacturer is the 'B' then.

What manufacturers should one avoid if any?

--
Adrian Smith