My answer to Is a boat made of fiberglass too fragile for circumnavigate the world?
Answer by Desmond Last:
As the owner and boat broker of Sydney Boat Sales for 12 years before my business was undermined by a nasty U.K based criminal group I was often asked this question.
A production or professionally manufactured fiberglass boat which is in sea-worthy and well-maintained condition fully equipped to sail round the World is of sufficient strength to ensure a safe circumnavigation. Fiberglass boats can suffer from osmosis. This is the absorption of saltwater into the layers of fiberglass. Always obtain a moisture analysis of the hull when buying a fiberglass boat.
However a steel boat is stronger but is a lot heavier per foot waterline length. Steel rusts. From the inside and outside. Always have the hull x-rayed before purchase.
A timber boat has a natural buoyancy factor that exceeds that of steel and fiber-glass and has better sound and heat insulation qualities. But over time it will suffer from expansion and contraction of its timber joints that will let allow water to enter the hull. Timber rots. Always have the boat inspected for rot before purchase.
A concrete boat will exceed the weight per foot of waterline length of all the above and may suffer from build quality and maintenance defects which will affect sea-worthiness. Where possible avoid purchasing a concrete boat to go off-shore. It may not be possible to get insurance.
A composite boat made of carbon-fiber will be very expensive. A composite boat of other materials may suffer build quality structural defects .
My advice is to stick to well-known production boats. Never ever even if you are hit by a bus and lose all commonsense buy a boat without an out of the water survey by a qualified experienced surveyor and a mechanical check of the engine incl an on- water test.