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Patrick
Willey of Garland, TX asks:
I
recently read an article comparing Fiberglass and Steel in
reference to use in Ocean passages for Trawlers. In summary,
it really did not sound very positive for fiberglass especially
for the possibility of hitting something offshore. Also, it
mentioned that the fiberglass could bubble and absorb water.
I currently own a fiberglass boat and have never had any problem
with blistering. Is it a concern in crossing oceans?
Dan
Streech responds:
Thank
you for your question regarding the comparison of fiberglass
and steel in reference to the strength of a trawler. I would
like to know which article you read so that I could answer
specifically to it.
The
subject of steel vs. fiberglass is of course a long running
and very emotional subject which can't be properly answered
in this forum. The general process seems to be that builders
of or proponents of steel vessels will emphatically claim
that steel is stronger than fiberglass. In fact, the strength
of a vessel (weather steel or fiberglass) is a very complicated
subject that depends on the design and quality of the vessel
in question.
A
well designed and heavily built fiberglass boat can be extremely
strong. A full displacement boat is not sensitive to weight,
so the hull can be quite thick and rugged. Put a heavy and
thick hull together with generous interior stringers and well-placed
and heavy bulkheads you have a tank ready for battle.
We
now have about 300,000 cumulative hours on our various Nordhavn
models. There have been two circumnavigations and countless
crossings of the Atlantic and Pacific oceans. There have been
several accidents including an N62 that hit a submerged jetty
at full speed in Hong Kong, an N46 that ended up high and
dry on a rocky beach in Mexico as well as other groundings
and collisions with buoys, docks and other boats. To date,
there has never been a structural failure or structural damage
either from the above mentioned accidents or from any of the
sea conditions ever encountered.
There
is the often asked question about hitting a floating container.
Many containers are reported lost from ships at sea, but to
date, I have never seen a container at sea nor have any of
our Nordhavn owners or anyone that I have ever talked to seen
a container floating at sea.
If
a Nordhavn did indeed somehow hit a floating container at
cruising speed, I think that there is a only a small chance
that the accident would hole the hull.
The
greater fear is the possibility of hitting something (much
more likely a log in Alaska than a container) with a stabilizer
fin. The fin is a 3 foot moment arm trying to rip the actuator
out of the hull at its attachment point. Thus, an extremely
strong foundation is needed for the stabilizer actuators so
that the hull does not flex or become distressed in an accident
with the stabilizers. In the 12 years that we have been producing
Nordhavns, there have been 5 or 6 accidents in which a stabilizer
fin has been ripped off without damage to the structure of
the hull.
So,
statistically, well-built fiberglass boats (not just Nordhavns)
have a very good track record.
As
for water absorption and blistering; yes, that can and has
been a problem on fiberglass boats, but it has been effectively
eliminated with the use of Vinylester resins and epoxy barrier
coats. Now as for rust… Oh wait, we don't have rust problems
with fiberglass boats.
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