When is a boat a ship?
You may have spoken to a ship's captain who may got a little annoyed when you referred to his or her vessel as a boat, while most boat captains usually wouldn't be concerned if you refer to their vessel as a ship.
Size does matter, and this is pretty much what ships are all about.
All ships are large boats, but not all boats are ships. Submarines, however, are always boats.
The definition of a boat is a vessel for transport by water, constructed to provide buoyancy by excluding water and shaped to give stability and permit propulsion. This includes small vessels, small vessels carried for use by larger ones such as lifeboats, vessels of any size built for navigation on rivers or other inland bodies of water, small ships such as fishing boats, or ships.
When a ship sinks you get in a boat when a boat sinks you get in the water.
Historically, a ship was a sailing vessel with at least three square-rigged masts and a full bowsprit.
Some say a boat can be lifted out of the water for repairs, while a ship spends all its life in the water and only leaves the water when it's decommissioned and cut up. Today that might be slightly incorrect as the picture below proves; a very large ship with many new ships well out of the water and far from being decommissioned.
The more scientific view would be that on a boat the centre of gravity is below the freeboard, whilst on a ship it is above. This means that a boat, such as submarines or smaller yachts, will lean inward when turning while a ship will heel outward.
The difference between a boat and a ship is which way they heel when turning.
In other words, a bicycle or a motorcycle will lean inward during a turn, a car or a truck will lean outward.
Same concept for boat vs. ship.
At Find a Crew™ we do say 'find a boat' because this includes of course ships, while 'find a ship' would not include all boats. So while a ship is a large boat, we suggest to never call an actual ship a boat if you wish to have any credibility as a mariner, or ever wish to be employed on a ship.
If there are several ships and several boats you usually talk about vessels or boats but not ships, because as mentioned earlier only some boats are ships, but all ships are large boats.
We consider that generally most non-submersible vessels over 30 meters (100ft) in length, or over 150 GRT could be considered to be ships as on such vessels the centre of gravity is usually well above the freeboard.
One very, very, very big ship carrying many, many big ships. Better not mess with that captain!