Cooling system for watercraft

A cooling system for watercraft comprising:

• a rechargeable battery capable of powering an electric propulsion device of a watercraft;
• a coolant channel through which coolant circulates to cool the battery;
• a cooling water channel through which cooling water flows, the cooling water containing seawater or fresh water acquired from outside sources;
• and
• a heat exchanger for exchanging heat between a primary channel and a secondary channel, wherein the primary channel communicates with the coolant channel and allows the coolant to flow therethrough, and wherein the secondary channel communicates with the cooling water channel and allows the cooling water to flow therethrough,
• wherein the cooling water channel comprises:
• a central water line which communicates with the secondary channel, and includes a water inlet for taking in the cooling water, a water outlet for discharging the cooling water, and a tank for storing the cooling water;
• a first bypass channel which communicates with the central water line so as to cause the flow of the cooling water to bypass the water inlet and the water outlet, thereby allowing the cooling water stored in the tank to circulate in the cooling water channel, and
• a first bypass valve arrangement which enables a selection of whether or not the cooling water is allowed to flow through the first bypass channel.