Arrangement and method for sealing a propeller shaft of a marine vessel

A method for sealing a propeller shaft of a marine vessel with a seal arrangement having:

• at least one bearing for rotatable supporting the propeller shaft,
• a bearing arrangement adjacent to said at least one bearing,
• a first lubrication arrangement comprising a first lubricant circulation line for conducting a first lubricant to said bearing arrangement and for conducting the first lubricant from said bearing arrangement, a first lubricant circulator configured to create a flow of the first lubricant in the first lubricant circulation line and in said bearing arrangement,
• a shaft seal arrangement for sealing the propeller shaft against sea water, and
• a second lubrication arrangement including a second lubricant circulation line for conducting a second lubricant to said shaft seal arrangement and for conducting the second lubricant from said shaft seal arrangement, a second lubricant circulator configured to create a flow of the second lubricant in the second lubricant circulation line and in said shaft seal arrangement,
• wherein the method comprises:
• providing a first heat exchanger in thermal contact with the first lubricant circulation line and in thermal contact with the second lubricant circulation line, and
• transferring thermal energy between first lubricant flowing in the first lubricant circulation line and second lubricant flowing in the second lubricant circulation line by means of the first heat exchanger, wherein said transferring of thermal energy via the first heat exchanger lowers a temperature of the second lubricant in said shaft seal arrangement.