WELL, LET'S NOT DO THAT AGAIN.

Disassembling, cleaning, and reassembling my boat's engine was a months-long lesson in hard work and frustration.

- ROGER HUGHES

DIY

Occasional grounding is an inevitable problem of navigating a yacht that draws 6 feet, 6 inches in the shallow Intracoastal Waterway. If you have a deep-draft boat like my 50-foot schooner, Britannia, and you happen to wander off the main channel, you can easily run aground. This does not normally cause damage for a long keel boat because the bottom is mostly soft black mud, but depending on how hard the boat goes on, it can be a quite a trial to refloat.

With any attempt to refloat, the propeller is whirling madly only a few feet from the muddy bottom. It is certain to disturb lots of silt and sludge, which then can be drawn into an engine-water-cooling intake.

Most freshwater-cooled marine diesel engines operate on the same principles: An impeller pump draws in cold seawater to cool the engine's hot, fresh water through a heat exchanger; the residual warmed seawater is then pumped out the back of the boat, usually through the exhaust.

The large mesh filters fitted to most boats' engine intakes will capture larger lumps of debris, such as seagrass and even small fish, but minute particles of sand and sludge can still pass through, clogging the seawater neoprene impeller and then working their way into the engine's heat exchanger and cooling passageways. The first sign of this trouble is often a rise in the engine's temperature, along with a reduction in revolutions and performance.

STOPPED IN HER TRACKS

This exact scenario occurred when we were traversing a 20-mile section of the Intracoastal between Titusville and New Smyrna Beach, on Florida's eastern coast, in spring 2022.