When replacing the original factory installed poor quality thru-hull fittings SO42DS owner Brent Meyer decided to also fit a bypass to a bronze Perko bilge strainer, so in extremis he can switch the engine coolant water to act as an additional bilge pump.
The fitting of a run-dry type impeller such as the Speedseal might be a valuable addition.
Below are pictures of the Speedseal Life. This replacement cover and internal mechanism take 10 minutes to remove the original water pump seal, and replace the Speedseal. The advantage is I can then remove it quickly without tools using the stainless steel knurled thumb screw and if by chance the raw water intake gets blocked, the pump can still run on the inner low friction plates to avoid damage. Available from www.speedseal.com