On a multiple bilge pump setup, can you T into an existing line or do you need to put another thru hull? If the thru hull is needed, do you just pop a hole next to the other one and install? Anything not obvious to think about there? I like the idea of a second beefy pump a bit higher to help in that situation.
I would put another hole in the side of the boat. Dont put a “T” because it will be back filling water back into the boat through the bilge pump that is not working. So, it would be making a continuous circle and removing little water.
Pool noodle is a good idea.
I was thinking about a wine bottle cork. Not the real cork but the foam type corks.
I always carry a stick of what I refer to as “Monkey-****”. It’s actually a stick of underwater epoxy that you “kneed” together to activate. It can be smeared over a tear in the hull or packed into a broken thru-hull fitting. Sets up real quick and bonds under water.
I also have a manual bilge pump.