sailors/cars in or on a ship?

[yuriya]

Hi, everyone! I know that generally we are on a ship and in a boat. However, if you're a sailor (or a crew) then you are in a ship rather than on a ship? And is my car in or on a ship or either is fine depending on the size (or structure) of the ship? Thanks in advance!
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Feel free to correct my sentences. I welcome them, not resent them!

[Koronas]

Generally, we will say "on a ship" unless we wish to stress the fact that something is inside and not on deck.

The people were on a ship when it foundered.
The people were still in the ship when they drowned.

[bhaisahab]

Hi, everyone! I know that generally we are on a ship and in a boat. However, if you're a sailor (or a crew) then you are in a ship rather than on a ship? And is my car in or on a ship or either is fine depending on the size (or structure) of the ship? Thanks in advance!
__________________
Feel free to correct my sentences. I welcome them, not resent them!

Sailors/crew are on a ship, they might be in a cabin on the ship. Your car is on the ship, on the vehicle deck.