What is an unsinkable boat?
Administratively, the notion of unsinkability no longer exists since 2005, following the revision of Division 224 (the division which governs the safety of pleasure craft and which is now called Division 240). Unsinkability is therefore detached from the norm.
Previously, to be unsinkable, a boat had to have buoyancy volumes in the bottom to float, but also in the tops (on the sides of the hull) to keep stability once the boat was full of water. This standard implied having an unsinkable volume far greater than the weight of the vessel.
The Etap sailboat yard or the Ultramar motorboat yard (two yards have now disappeared) produced unsinkable certified boats (they were not the only ones). The chests and planks were filled with injected foam.
In addition to the safety aspect ("I sail on a boat that doesn't sink"), the main advantage was that I didn't have to carry a life raft. On the downside, these boats lacked storage space, the chests were condemned by foam.
And today?
If the notion of unsinkability is now detached from the standard, it is always possible for a shipyard to offer unsinkable boats to their customers. But most yards don't, for others it's just an option. Finally, some consider that it is not conscientious to sell sinking boats. This is the case, for example, of Pogo Structure, all the boats of which float even filled with water.
Contrary to a time when an unsinkable boat had to meet the criteria of the standard, the shipyard Structure proposes sailing boats which float, but which will not be navigable full of water. This already offers the advantage of not having to leave it in the event of damage and waiting for help - feet in the water - but always on board. A safer situation than in a life raft.
A life raft for everyone
This notion of insubmersibility does not dispense with a life raft! It is now mandatory for all boats. This is particularly justified in the event of an uncontrolled fire where it is necessary to disembark quickly.
This information is valid for sailboats and motorboats. Light boats, on the other hand, must all be unsinkable. Light sail dinghies, for example, must always be unsinkable.
Similarly, some racing yacht gauges require unsinkable volumes or even watertight bulkheads. This is the case for the Mini 6.50 or Class 40 yachts. But in this case it is the gauge and not the law that imposes this constraint.
Here a Boston Whaler cut with its shown foam injected between the hull and deck.
