I have a Max Power tunnel bow thruster on my Hunter 49, I was told this is a sealed unit in the tunnel no maintenance required, that being said I have a fellow 49 owner have the seals go bad. The maintenance note is to check once a year that their is no calcium buildup on the shafts behind the props and lube the shafts with silicone grease. Has anyone had any problems with their Max Power bow thrusters.