Originally Posted by billyruffn
Talk to your home owner's / renter's insurance broker/company. You may find out that you're covered as far as personal liability is concerned up to the limits on your homeowner's / renter's insurance.
Others here, more knowledgeable than I, will certainly offer better insight and advice.
I think this is a great place to start.. You're not insuring for any kind of replacement value, the marina wants the coverage in case you do damage to the docks or neighbours..
Oh... and same caveat!