Does anyone know if my boat insurance will cover another boat that I am operating?
If not can I take a policy out on a boat I do not own?

If the boat you are operating has insurance, then it's primary.

Your liability follows you. Physical damage wouldn't.

There are so many aspects - how often do you borrow the boat?

Why not get the owner to add you to their policy as a operator? (assuming said owner has the boat insured). It may not increase their insurance cost, but you could offer to pay some portion of the policy regardless, and you both win, as one operator updated policy would likely be the least expensive, and also a win for the relationship with someone who allows you to use their boat.

Thank you for the replies, the boat is currently insured and my boat is insured as well.
I am required to have $100K liability insurance to participate in a championship this weekend.
My boat is in the shop for some work on the motor. My friends boat is insured by his employer. (He owns it)
So far only word from my insurance is no short term policy for non commercial.
Still waiting to see if my policy will cover another boat I am using.
I have two boats, I am sure there is a hungry agent out there....

Progressive said if I added my SIL as an operator, IT WOULD jack up my premium, maybe $30 more per month. The additional amount also depends on how old this other party is, how much boating experience this person has, and if this person has gone thru a Boaters Safety Course.