Commercial isn't the keyword. Many pleasure craft are larger than commercial
vessels; think about fishing boats.
A tanker is more than a commercial vessel; it's big and may be constrained
in it's ability to move: a small boat must stay clear.

wrote in message
oups.com...
are you sure? I read that commercial vessels always have the right of
way over pleasure crafts... i.e. a tanker wont stop to let a 19 ft
boat from the right go by

Matt