George, it is technically possible to cross an ocean in a small powerboat but the odds of a successful crossing or even survival are so small that few people attempt it. The key issues are:
1. Typical ocean swell is 8-9 minimum. Even under ideal conditions, you will not be able to maintain high planing speed in a 30’ powerboat for long before either the
boat breaks down or you break down. It will be super uncomfortable.
2. The
fuel requirement at 1 mpg should be at least 2-3,000 gallons. You cannot fit this into the
boat. There are planing boats that are designed to cross oceans, typically around 150 ft and above, $15 million and above.
3. If you go slow in order to be comfortable and save on
fuel, then you need a boat than can survive non ideal conditions as your
weather window will be long. This is typically a
keel sailboat (cheap) or a custom designed
trawler (expensive).
If you want to enjoy local
motor boating definite get the
power boat and have a blast. Expect its value to decline by more than half in two years. Then sell and buy a sailboat.