Entrance Sunart we were met my F5/6 And struggled to make headway on top of which the the coolant alarm went off. Put some sail up and eased up on the engine. Decide to head to Tobermory - more chance of getting help if need. Went to pontoon. had to borrow a drill to repair a wing nut that sheering on the raw water inlet for the engine - Having checked all, only possible issue was coolant seem low.