Is it a boat or a ship?

What’s the difference between a boat and a ship?

I had always thought that a boat is an open vessel, such as a simple rowing boat, and a ship has at least one deck closing off the upper area. But this deinition doesn’t work well for submarines (which are boats) and tugboats. So I started looking around the internet for definitions.

I quickly found this definition: as a general rule, a boat can fit onto a ship, but a ship cannot fit onto a boat. I thought to myself, how stupid is that? A submarine (think big nuclear submarine) doesn’t fit onto a ship. So I kept looking.

I eventually found another definition. On a boat the centre of gravity is below the freeboard, on a ship it is above. This means a boat, such as a submarine, will lean into a curve when turning and a ship will lean out. This satisfied me, because it’s more technical. When I told Sonja, she just said “What?!”. So I kept looking.

Eventually I came back to the first definition I found, but with a better explanation. It all depends on whether or not the vessel in question is capable of carrying another vessel in a ready-to-use condition. If it can, it’s a ship. If it can’t, it’s a boat.

So, an 80 foot megayacht that is fitted with fantail davits for carrying a 20 foot runabout is classified as a ship. The runabout is a boat. If the megayacht did NOT have those davits, and couldn’t carry that runabout, then the megayacht itself would be classified as a boat. However, once you bring lifeboats aboard, she becomes a ship. So, if you were to build an aircraft carrier and somehow leave off the ability to carry lifeboats, launches, or the captain’s gig, then you’d have a really big boat on your hands instead of a really big ship.

By the way, this is why traditionally all submarines are referred to as boats, and not ships. Now, some subs are fitted with a DDS (Dry Deck Shelter) for storing and launching mini-submersibles called SDVs (Swimmer/SEAL Delivery Vehicles), and such subs are technically ships, but longstanding tradition decrees that they are still called boats.

Where does this leave us? The real question was whether Yamoya is a boat or a ship. Using the reasoning above, she is a ship because she will have the ability to carry our dinghy, which is a boat. 🙂

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