Whats the difference between a boat and a ship?

Answer 1

As an old Merchant seaman from the 1960's and a graduate of Leith Nautical College in Edinburgh, I can tell you clearly the definition of a ship, versus a boat, is this: A boat can fit into or can be carried by a ship but not vice versa.

Size is not the only determinant. Boats are usually used either on rivers or lakes, or near the coast, and rarely make transoceanic voyages. Boats also are usually specialized (fishing, yachting, etc.). A ship is larger and has one continuous main deck. Older definitions refer to the type, size and number of sails, but that's

old-fashioned.

Vikings had long boats and the Germans had U boats so it's not the length a boat has one continuous deck. A boat becomes a ship when it has more than one deck.

A ship carries life boats, but a boat does not carry the lifeboats.

According to the United States Navy a boat is "A small craft capable of being carried aboard a ship." (NAVEDTRA 14325, pg. AI-2). But hold on, in true navy fashion the same manual gives a different definition on page 7-5 it says, "The term boat refers to a non-commissioned waterborne vessel that is not designated as a service

craft.

This rule of thumb has worked well for me over a 20+ year Navy career: While taking a turn at the same speed, a boat leans TOWARD the center of a turn, while a ship leans AWAY from it. Of course this is caused by different stability & bouyancy characteristics related to the draft and size of the craft.

A ship is a "Any large vessel capable of extended independent operation." (pg. AI-11)

Then again when I was in the navy the Blue Jacket's Manual defined a boat as being different from a ship by vessel length. I forget what the length was but remember it pointed out that submarines were considered boats even though the SSBNs where longer than the length a boat was supposed to be.

I think the term is ubiquitous, but generally means a relatively small vessel and a ship is a relatively large vessel.

Ships are large. Ships are sometimes used to go long distances from place to place on the ocean. From the old boatswain: A ship can carry a boat, so what does that mean? To get a boat on a ship, you have to lift it at two points. If you tried that with a ship, the thing would fall apart. The difference is in the structure. This limits the size of boats. A sub is a boat because it is built to withstand great pressures from all sides when it is submerged. A ship needs the pressure from the bottom equal for the whole length or it will break up. That is why when ships run around, they do break up after a short time. The Santa Maria was only 70 feet long, a WW 1 sub was about 111 feet, and the LCM-6 (landing craft mechanized) was about 75 feet. These were lifted by 70 ton booms and put on the transport ships to go to the landings.

Realistically, there is no difference between the two, except by tradition. What we choose to label a boat vs a ship has no objective basis. That is, one cannot say that by having characteristics X, Y, and Z, a watercraft must be called a ship (or a boat) - there are simply too many exceptions. There may be generalizations, but you'll almost always be able to easily find something that is traditionally called the opposite of what that "rule of thumb" describes. In the end, it's just cultural tradition as to what we label something.