A hull that displaces water as it moves forward through the water. As the hull plows forward, it creates a wave. The boat rides in the trough of the wave, and sinks down into it. Eventually, the wave becomes the same length of the boat, and the two move together as one unit, and the boat cannot move any faster. The boat will not have the power to climb over out of the wave. This is called "maximum theoretical hull speed". The longer the hull, the faster you can go.
A hull that climbs on top of, and planes upon the water. The effect is similar to skipping a stone across the water, or waterskis riding on top of the water, instead of plowing and displacing water.
Smaller powerboats are usually planing hulls. Large power yachts are usually displacement hulls. Older, monohull sailboats are usually displacement hulls. Many modern racing sailboats have planing hulls that allow them to get on top of the water when sailing downwind.
Multihull (catamaran/trimaran) sailboats are displacement hulls, but they don't have heavy, keel ballasts to keep them upright because they have two or more hulls to provide stability.
Keel: The purpose of a keel on a sailboat is to provide stability and prevent "leeway" or sideways movement while sailing. There are many types of keels:
Full, cutaway forefoot, fin, wing, swing, shoal, etc. Some boats use centerboards or daggerboards which are a keel that you can lift up when in shallow water.
I don't know that I'd say that a sailboat is "less" maintenance, but it certainly is "different" maintenance. I'd rather work on deck, rigging
, sails and electrical systems than diesel engines and their associated systems.
You need to decide where you want your maintenance and operation dollars to go: (Power yacht)Engine mechanical repairs
, upkeep and fuel
or (Sail yacht) deck, rigging
, sails and a greatly less significant portion of engine upkeep for the auxiliary engine.
You also need to decide which is more important to you: The destination or the journey. If just getting from A to B is more important, then buy a motor yacht. If the experience of the journey is more important, then buy a sailboat.
I tend to agree with Siamese. Sailing is also a sport and a tradition, not just a mode of transport. It takes a little time and dedication to learn, but it's not rocket surgery. You can do it.
But if the only thing you want to learn is how to get somewhere fast, and the only physical exertion you want to make is the arm that operates the throttle lever, then buy a motor yacht.