Good point, Smokey - that OSSLO thing is just a handy mnemonic for the basics. I always stay well clear of larger craft on the Chesapeake, examples being subs, warships, container vessels, tugs with barges, etc. Anyone who can really damage me gets right of way in my book, even say large motor yachts.
Reminds me of a joke:
Captain of battleship on radio: Vessel ahead, give way.
Vessel: I can't, recommend you change course.
Cap: This is a US warship, you must give way.
Vessel: Sorry but I can't, suggest you change course.
Cap: This is your last warning, I am a battleship, change course immediately, I will not.
Vessel: Suit yourself, Captain, I cannot. This is a lighthouse.
Reminds me of a joke:
Captain of battleship on radio: Vessel ahead, give way.
Vessel: I can't, recommend you change course.
Cap: This is a US warship, you must give way.
Vessel: Sorry but I can't, suggest you change course.
Cap: This is your last warning, I am a battleship, change course immediately, I will not.
Vessel: Suit yourself, Captain, I cannot. This is a lighthouse.