What are small ships called?

Small ships are called dinghy, dory, rowboat. a small boat of shallow draft with cross thwarts for seats and rowlocks for oars with which it is propelled.

I remember in times before, small ships are used in the waters without proper machinery. Are these the ones they used and isn’t it dangerous?

With most they already have. They make sure it is safe but of course you cannot control any incidents or currents.