Hi Gordon!
It depends on *why* you want to register speed-boat.com as to how I would answer that...
For example, if you are planning to launch a site that sells speed boats, I would recommend trying:
fastspeedboats.com
speedboatsale.com
buyspeedboats.com
If you are planning to launch a personal site to boast about your own little personal speed boat, I would recommend trying:
lovemyspeedboat.com
Lets say you were going to launch a site around the idea of how to buy a speed boat, best places to take your speed boat, speed boat races & events - general speed boat stuff:
speedboatfun.com
speedboatinfo.com
Then there's always:
superfastspeedboats.com
speedboatfans.com
bestspeedboatsonline.com
buysellspeedboats.com
Endless ideas... Consider your primary focus for the site, potential keywords your targeted audience might use, and just go from there