Modern ships are made of steel rather than wood because steel is stronger and longer lasting.
There are some boat's with simple motors, some small fishing boats, however most boats have motors much like a car's engine. Some of the big boats, cruise lines or similar, will have motors larger than most vehicles.
It is based on the number of passengers and crew that the ship can carry. There are more boats than needed in case some of the boats would be damaged.
some are some arent it depends on who made them
some are and some arent. it depends you have to check on the box what material its made from
Plastic reinforced by fibreglass, along with some plastic foam for certain parts of the boats.
The ships could not hold all the men trying to escape back to England, they would have sunk trying to get them all. So men with large enough fishing boats and cruise boats risked their lives to get the rest of the men. They made many trips getting hundreds of thousands French and Brits. Some of the Brits were not saved. The Germans captured them and put them into POW camps.
I heard some where that someone made 2000 boats but another person may have done more by now.
Boats made of cement can float as can those made of steel. They do it by displacing water. See the link below for some history and reference to a book about cement boats.
Some boats are made with wood. Which luckily you can watch the process of how traditional boats are made. Watch full video on youtube @insideghana1957
some are some arent
some are some arent
Some older large vessels need to be pushed into position by pilot boats in tight spaces because they only have one set of screws (propellers) at the aft (rear) for forward propulsion. Modern day cruise ships have several sets of omni-directional screws for greater maneuverability, but still need pilot boats for emergency directional changes as well as communication to aid in navigation in tight spaces. Yes, azipods and bow-thrusters do help for maneuverability, but it's a tugboat's job to help steer the vessel. The pilot boat's job is to tell the captain how to navigate in waters that he and the helmsman are unfamiliar with. So, cruise ships still need pilot boats (and always will) but most don't need tugboats.