Fixing 5 Common Onboard Problems

If you know you could ruin a brass ball with a rubber mallet, or if you don't even understand why that would indicate poor mechanical skills, you're probably best off relying on professionals for on-board repairs. But every boat owner should know these five simple solutions to common problems aboard.

1.Shore power cords trip repeatedly or won't reset.
Starting with the obvious, breakers often trip simply because too much equipment is running. To know for sure, turn everything off and then watch the ammeter on the main electrical panel as you energize each system. If you're creeping close to the capacity of the shore cord ? either 30 or 50 amps, depending on your cord ? look for equipment to turn off that won't be missed, like the water heater or a stateroom air conditioner.

Bigger problems occur when too many boats are drawing too much power from the dock. The voltmeter on your panel should read at least 220 for 50-amp cords or 110 for 30-amp cords. Operating equipment at lower voltage can damage components, so it might be wise to switch to the generator until dock voltage rises.

If the shore cord is dead but both dockside and main breakers on the panel are on, follow wires inside the boat leading away from the shore cord receptacle or CableMaster storage drum. There should be another circuit breaker just a few feet away.

2. Air conditioners won't cool.
If some AC units blow cold but one doesn't, it's time for a technician. But if the whole boat is hot, the likely problem is a clogged sea strainer. Turn off main breakers for the pump and all air conditioners, close the sea valve, open the strainer top (which might require a spanner wrench) and pull out the metal or plastic basket. Without soaking the pump in seawater, crack open the sea valve to make sure water flows freely from the strainer. If not, the through-hull fitting might have debris stuck in it, requiring a trip overboard. Clean and replace the strainer basket. Close the sea strainer, open the valve and check the top for leaks. Switch on breakers for the pump and at least one AC unit; set its thermostat much colder than the room and make sure water flows from the overboard discharge.

3. The generator won't run or it runs but won't provide electricity.
Most generators shut themselves off if they lose oil pressure or run hot. First, turn off the main circuit breaker. Next, check oil and external coolant reservoir levels. Check sea strainer and fuel filter bowls with a flashlight for obvious problems, and also look for seawater leaks. Reset the push button or switch for the shutdown system, almost always near the start switch mounted on the generator. Start it and immediately check for normal seawater flow from the exhaust. If there's none, shut it down and call a mechanic. But if water is flowing, monitor coolant temperature for a while without an electrical load. If the generator still overheats, let it cool for a few hours and then check the coolant level in the heat exchanger directly, as external reservoirs often don't function properly.

If the generator runs but won't provide AC power, reset the main circuit breaker typically mounted on the side or back of the generator near the start switch.

4. The bow thruster won't thrust.
If the joystick itself isn't getting power, the problem is likely a circuit breaker somewhere near the helm or on the main electrical panel. If the thruster quits while running, it probably got too hot and tripped itself offline. Most reset themselves in a few minutes. Also check large circuit breakers or fuses, which protect DC-powered thrusters. Look under the cabin sole or forward stateroom bed. If there are batteries in the bow, the fuse or circuit breaker will be there too. If the thruster instead gets power from main batteries, the fuse or breaker will be somewhere in the engine room or near main battery switches.

5. Engine fuel problems.
If one engine suddenly won't run or runs very rough, even at idle, the fuel system might be sucking air, which is going to require a mechanic but should only affect that engine. Clogged fuel filters may affect one or both engines, but problems almost always crop up at cruising speed while still allowing engines to idle normally. Select a course that is comfortable and then check each Racor fuel filter bowl with a flashlight. Diesel fuel should be clear amber or red; if it resembles coffee with milk, there is water in the fuel that can quickly damage the engine. Shut down the worst engine first to maintain headway with the other. Open the valve on the bottom of the fuel filter and drain the water into a fuel-resistant container. Close the valve, fire up the engine and check the other side.

When changing fuel filters, know how to use priming pumps and check them each time before proceeding. Shut off an engine and its fuel supply valve, remove and replace the fuel filter, cover gasket and T-handle O-ring. Open the valve, operate the priming pump and then start the engine. Run that engine for a while to ensure it's primed before stopping the other.