Boat Vs Ship What Is The Difference: Guide

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Have you ever thought that a ship and boat aren’t the same things?

Well, if you haven’t, then do know that they aren’t quite the same. In fact, there are plenty of differences that set them apart.

With that said, what’s the difference between a ship and a boat?

To be honest, this isn’t the easiest question to answer. But hopefully, our guidelines below will be able to help you.

How Are Ship And Boat Defined?

First, we should have a look at the definitions of “ship” and “boat.”

According to the Merriam-Webster dictionary, a boat is “a small vessel for travel on water.” Aside from that, the dictionary also considers the word “boat” synonymous to “ship.”

Conversely, a ship is defined as a “large seagoing vessel.” The second definition ofa ship is a sailing vessel that has a bowsprit, as well as usually 3 masts, each composed of a topgallant mast, a topmast, and a lower mast.Finally, a ship is defined as a boat, especially one propelled by sail or power.

Not too difficult, right? A large vessel is a ship and a small vessel is a boat.

It isn’t as easy as it may seem though.

Where is the line that separates ships from boats? Is there a formal threshold of height, displacement, or weight that separates ships from boats? No, there are no universal rules or formal definitions that separate ships from boats.

The Navy Institute’s opinion

Since there are no formal definitions of ships and boats, it’s often more practical to go by colloquial distinctions between ships and boats. That is, if most of the people call a vessel a ship, then you should do that as well.

With that said, there still are some features that people follow when classifying a vessel as a boat or ship.

A common definition of boats and ships is that “you can put a boat onto a ship, but no a ship on a boat.” The US Naval Institute shares this approach as well. This is actually more or less precise since, as mentioned above, the Merriam-Webster dictionary defines a ship as a larger seagoing vessel, while a boat is a small vessel.

And the “boat goes onto a ship” rule of thumb isn’t something people have decided – more likely, it’s just a feature that has been observed by naval specialists. And due to the absence of precise and formal definitions, this has become one of the informal distinguishing features between ships and boats.

Another feature that the US Naval Institute points out is that if a vessel has a permanent crew with a commanding officer, it is more than likely a ship. Notice the use of “more than likely” by the US Naval Institute – a vessel with a permanent crew is not necessarily a ship.

Conversely, if a vessel is only manned part of the time – when it is in actual use, for example – then it probably is a boat.

The third distinction brought up by the Naval Institute is that ships are designed to navigate in deep waters, though this doesn’t always apply to boats or ships.

NAVEDTRA 14325 definition

The Naval Education and Training Professional Development And Technology Center’s Basic Military Requirements course gives its own definition to boats.

Under Chapter 7, a boat is defined as a “noncommissioned waterborne vessel that is not designated as a service craft.” Aside from that, the course describes that a boat is capable of limited independent operation. Among vessels that fall into this category are motor whaleboats, officer/personnel boats, and utility boats.

The confusion between ships and boats

Not only are there no formal definitions and distinguishing features between ships and boats, but people are commonly using the two terms interchangeably. Interestingly, the Merriam-Webster dictionary defines “ship” as boat and “boat” as ship because that’s the manner many people use the terms.

Aside from that, the two terms are sometimes used not as intended by their definitions.

One example brought up by the US Naval Institute is the PT boat (patrol torpedo boat). These vessels have been organized and used as ships – that is, they had a permanent crew – but have been nonetheless called boats.

Another example is submarines. Technically, they are ships, but they are called boats against logic like it is with PT boats.

The reason for the use of the term “boat” with submarines is relatively simple. Original submarines were very small and were manned only when in use, which satisfies the definition given by the US Naval Institute. And while submarines have developed into larger vessels and started to satisfy the description of ships, the term “boat” stuck to them.

And an even weirder thing is that in the US, submarines are identified by the prefix USS, which stands for United States Ship! So you could say that submarines formally are ships, but they are known as boats among the crew.

The US Naval Institute writes that some submariners attempted to start calling submarines ships, but unsuccessfully. The term “boat” is stuck to submarines for good, even though they do have all the key features of boats.

Strangely enough, personnel of air wings on aircraft carriers also sometimes refer to aircraft carriers as boats, whereas the permanent personnel of aircraft carriers do consider carriers to be ships. This may be a case of lack of information among non-specialists though.

Oh, and aside from that, there is one problem with the definition that “boats go on ships.” Some police boats, yachts, ferries, fishing boats, etc. carry small lifeboats, but they aren’t considered ships. Aside from that, smaller ships may be carried on bigger ships, and those smaller ships aren’t getting demoted to a boat.

So yeah, there are plenty of imprecise distinguishing features and definitions that don’t really help you categorize a vessel correctly. With that said, the guidelines and rules given above should allow you to pretty easily make a distinction between different vessel sizes.

Differences Between Boats and Ships

Rules like “a ship can carry a boat” or “ships are larger than boats” can help you distinguish between the two vessel types, but they are not always quite enough. Aside from that, there actually are some other features that generally set boats and ships apart.

Below, let’s overview the main features that could help you distinguish a ship from a boat, including those that we’ve overviewed above.

Vessel size

We’ve already overviewed this one pretty in-depth. A ship is a large vessel, while a boat is a small vessel. And when this rule of thumb is insufficient, you may make use of the rule “boats go onto ships, but ships don’t go onto boats.” While not accurate 100% of the time, these two rules of thumb should allow you to relatively easily distinguish between boats and ships.


Means of propulsion is a thing that we haven’t covered above. How a boat is propelled is actually a solid distinguishing feature. However, not all definitions of “boat” and “ship” specify how they are propelled.

First, we have the Merriam-Webster dictionary’s3-mast rule for sailing boats. This rule actually makes a lot of sense since boats oftendon’t have the space or cargo capacity to hold 3 masts. Aside from that, the weight of 3 masts may even harm a smaller sailing vessel by weighing it down.

Another feature that the Merriam-Webster dictionary points out is rowing – the dictionary recommends that you sing the children’s song “Row Your Boat” when unable to distinguish between a boat and ship. As the dictionary indicates, “row your ship” sounds odd.

This little detail allows us to come up with a new general rule – if a vessel can be propelled by manpower, e.g. paddles or pedals, then it most likely is a boat.There is no way you can efficiently propel a large vessel by manpower.

With that said, this rule doesn’t apply to larger boats that are too heavy to be propelled by manpower. Thus, the rule above applies only to smaller vessels. If a vessel is propelled by manpower, then you can be nearly certain that it is a boat.

When it comes to large boats and ships, they are usually propelled by engines that may be powered by electricity, gas, diesel, and even nuclear energy. Perhaps the only 100% rule that works with these types of engines is that if a vessel is propelled by a nuclear reactor, then it is a ship. This applies to nuclear-powered submarines as well (though they are still called boats by the crew).

Otherwise, ifthe propulsion method doesn’t allow you to distinguish between a boat and ship, then have a look at other features.For example, if a diesel-powered vessel can take other vessels onboard, then it’s probably a ship. You may also make use of the other features that we’ll talk in a bit.

Operational areas

Ships most often operate in oceans and high seas. It’s a common occurrence for ships to travel from continent to continent, especially transporting cargo.

Boats, on the other hand, usually operate in coastal or inland waters. Since they are smaller, it is easier for them to maneuver in smaller water bodies and streams.

Another thing to pay attention to is the independence of the vessel. A ship can operate independently at any point in the world, especially in oceanic waters, whereas boats often are not capable of independent operation far from the shore.


A pretty big distinguishing feature between ships and boats is technology. The differences in technology are due to the varying purposes of ships and boats.

As mentioned above, ships are usually operated in high seas and oceans, while boats are typically operated in inland or coastal waters. Needless to say, the difference in the operational area implies some crucial differences between technology on ships and boats.

Ships have a need for more robust and complex navigational and communication systems. This may partly be due to the purpose carried out by the ships (e.g. military).

In inland or coastal waters, simpler navigational and communication systems do mostly suffice. There may not be as strict requirements for their reliability, and the smaller scale of operation does not need as complex equipment. Not only that, but boats cannot carry the bulk of equipment that ships can.


The construction differences between boats and ships are also due to the differences in the vessels’ purpose.

Ships are designed much more durable since they are required to take on board a large amount of heavy machinery. Ships are also required to be reliable since they cover thousands of miles throughout their service.

Boats, on the other hand, don’t have as strict construction standards. They can also be quite robust, but not as robust as ships. Well, this simply is not needed in boats since they don’t cover as much distance, and their purposes are “simpler.”

It’s also sometimes said that if a vessel has only 1 deck, then it is a boat. But if a vessel has more than 1 deck, then it’s a ship. This simple rule may work well in some cases, but probably not all.


We’ve overviewed crew above, and the rule is simple – if a vessel has a permanent crew that is onboard no matter whether the vessel is active or not, then that vessel is most likely a ship.But if a vessel has crew only at the time of operation, then it’s probably a boat.

This is a simple rule that works pretty well, but it also may have its shortcomings. It won’t always be precise,but it should allow you to make a good guess, especially if combined with other features.

Cargo capacity

Cargo capacity will also significantly differ between ships and boats. Since ships are larger than boats, then they are going to have much higher cargo capacity. An aircraft carrier, for example, can take much more equipment and crew than a yacht (which are mostly considered boats).

With that said, there are no strict definitions or thresholds that would allow you to separate a ship from a boat based on just their cargo capacity. The definitions for “boat” and “ship”are pretty blurry, and so is the distinction in cargo capacity between boats and ships.


Finally, a pretty good way of distinguishing between watercraft types is having a look at what it is.

For reference, here are some common boat and ship types:


  • Hand-propelled boats (kayaks, canoes, etc).
  • Sailing vessels that have fewer than 3 masts as per the definition of the Merriam-Webster dictionary.
  • Motor boats.
  • Fishing boats (mostly recreational).


  • Military vessels (including submarines, though they are traditionally called boats).
  • Sailing vessels that have 3 or more masts.
  • Commercial vessels.
  • Fishing vessels (mostly commercial).
  • Cruise vessels.

This simple list should allow you to get a clear distinction in most cases. But in the cases where you can’t separate a boat from a ship, you may make use of the other features we’ve talked about.

What If You Can’t Make A Distinction?

It’s sometimes difficult to make a distinction between a boat and a ship. Even specialists and watercraft crew may have a hard time in some cases.

So, if you don’t know a vessel’s type, how do you refer to it?

Well, we’ve just given you one word for it – vessel. We’ve repeated this term a few times throughout this post.

Now, some people may argue that a vessel is a container for something, usually something liquid, and they would not be wrong. However, “vessel” also means“a watercraft bigger than a rowboat.” If you don’t know what you are looking at, then you may use the term “vessel.”

Another term we’ve used a couple of times earlier is “watercraft.” Though the Merriam-Webster dictionary defines this term differently – as “ship” and “boat”– the terms “watercraft” and “vessel” are essentially the same thing.

Final Words

Well, it turns out that trying to distinguish between a boat and a ship is a very confusing matter. You have no formal and official definitions to go by – all you have are some rules of thumb and general features that somewhat set boats and ships apart.

However, most of the time, things like “boats can go onto ships” or “a boat is what you get into from a sinking ship” should be able to work.These aren’t precise definitions, but they should do the job most of the time.

When you can’t identify a boat by such simple rules, then pay attention to the features that we’ve talked about above. These again may not be 100% precise, but they should do a pretty good job of setting the two types of vessels apart.

And finally, if you don’t know what you are looking at, go the safe road and call it a vessel or watercraft. Not that you will necessarily get yourself embarrassed if you mislabel a ship, but if your profession does require you to know the differences between boats and ships,then playing safe may be a good option.