System Check

You're not going to fix every problem yourself. But with a grasp of your yacht's complex systems, you can be more self-sufficient and point troubleshooters in the right direction.

June 18, 2009



1. Davit, Dinghy, and Beyond

Check that dinghy batteries are charged, engines start, and drain plugs are installed before launching. Engines stored with fuel stabilizer should crank right up, but add fresh gas as soon as possible and consider a new spark plug. If the boat was stored without running stabilizer through the engine first, particularly with E-10 fuel, the same advice applies, but don’t go far without a paddle and a radio.


2. Fuel Fixes

The money saved at “rustic” fuel docks sometimes isn’t worth it. If you suspect fuel trouble, idle the engines and select a course that won’t roll the peanut butter out of a jar, and then check each clear Racor fuel filter bowl with a flashlight. Diesel fuel should be clear amber or red; if it resembles diluted milk, there is water in the fuel which could quickly damage the engine. With or without water in the bowl, if engines won’t turn cruising rpm, fuel filters need to be changed. Generator pickups are usually higher in the fuel tank, so they likely will be okay for a while. Before opening filters, make sure priming pumps work, and know how to use them, since diesels won’t tolerate even a little air. Shut down the worst engine first (to maintain headway with the other), and open the valve on the bottom of the fuel filter, draining the water into a fuelresistant container. Close the valve, fire up the engine, and check the other side. Shut off the fuel supply valve, replace the fuel filter, cover gasket, and “T-handle” O-ring. Run that engine for a while to ensure it primed before stopping the other. On engines that use 10-micron filter elements (blue for the Racor brand), the secondary filters mounted on the engine should be fine for a while. Since red Racor elements filter to 30 microns, some debris will pass through to those 10-micron secondary filters. Head to a close port or be prepared to change those, too.

3. Cold Comfort


The air conditioner seawater pump runs more in a week than many yachts’ engines accumulate in a year, so fouled strainers are common. If the whole boat is hot, turn off power to the pump and all individual units, and clean the sea strainer (in the engineroom or pump room on most yachts over 40 feet). To ensure the through-hull fitting isn’t clogged, a technician will usually open the strainer top, then crack the sea valve to see if there’s flow-being careful not to soak the seawater pump. Turn on the pump and one AC unit, set its thermostat much colder than the room, and check that water flows from the overboard discharge. If one room is hot, the compressor coils in the engineroom or evaporator coils in the stateroom might be covered in ice. Turn off the unit and let it thaw, and clean the return air filter in the stateroom. When you start the unit again, set the fan speed higher than it was when the unit froze.

4. Fresh Challenges

** **Like air conditioners, most watermaker problems stem from low seawater flow. Between the sea strainer and watermaker control panel, a set of filters strains incoming seawater to 5 microns-finer than most engine fuel filters. Change them when feedwater pressure drops too low. If the watermaker seems fine but tanks aren’t filling, try removing and scrubbing the salinity probe with a clean rag and water, and make sure the wires are connected to the diversion valve, both located somewhere downstream of the membranes. When water tanks run dry, alternating-current freshwater pumps turn themselves off when pressure drops too low. On some boats the backup DC pump will prime and activate the AC pump. If not, technicians look for a pressure switch on the pump (between the boat wires and pump motor wires). Lift the small metal lever on the side of the pressure switch upward slightly until the pump runs, but don’t lift it too far, or it will turn the pump off again.


5. Genset Know-How

****Most generators will shut themselves off if they lose oil pressure, overheat, or lose seawater flow. Check sea-strainer and fuel-filter bowls with a flashlight for obvious problems, and look for seawater leaks. Reset the switch for the shutdown system (near the start switch mounted on the generator), fire it up, and immediately check for normal seawater flow from the exhaust. If there is none, check the belt. You may need to replace the seawater pump-it’s often easier to change the entire pump than just the impeller. Try again, monitoring coolant temperature for a while without an electrical load. If it is still overheating, let it cool and then check the coolant level in the heat exchanger directly, as external reservoirs often don’t work. If the generator runs but won’t provide AC power, reset the main circuit breaker, often mounted on the side or back of the generator, or very close to it on a bulkhead.

6. Good Call


As many as five telephone sources are typically tied into one central phone system, with manual control of those systems guests can access-blocking satellite, for example, when cellular is available, or restricting landlines if they’re being billed through a hotel. When all else fails, check equipment circuit breakers and go directly to the unit handset to place a call. VoIP and some cellular systems don’t have a handset, but all telephone sources should have hard-wired and labeled phone jacks located near, but independent of, the central phone system. Plug a household corded or cordless phone or fax machine directly into the appropriate jack and dial away, even if the central phone system is dead. System tip: Satellite phones have one jack for voice and another for fax. Others use the same jack for both functions.

7. Power Play

American yacht builders favor two sets of batteries with independent chargers. Everything that doesn’t work will likely be in one section of the DC circuit breaker panel, often labeled 12 or 24 volt. European boats often just have 24-volt wiring and use internally fused 24- to 12-volt converters for electronics that won’t tolerate the higher voltage, typically located near the offending equipment. Viking and a few others distribute 12 volts throughout the boat, with a “series-parallel switch” to create 24 volts only for engine starting.

8. Rising Water

Knowing the boat is key, especially the location of all through-hull penetrations. Some boats have one interconnected bilge so a leak near the bow might flood the stern. Follow the moving water upstream to the leak. Other boats have watertight bulkheads with pumps and alarms in each, making leaks quicker to find.

9. The Thrust of the Matter

DC-powered bow thrusters will trip off if they get too hot from running too long, but should reset themselves a minute or so later. If not, look under the cabin sole near the bow. If windlass batteries are there, the circuit breaker will be, too. If not, it gets power from the main batteries and the breaker will be in the engineroom near the battery switches (occasionally there are switches in both locations).

10. Weighing Choices

Windlasses usually have two breakers, a toggle on the main DC circuit breaker panel that powers only the controls, plus a resettable push button on a DC subpanel near the battery switches, typically in the engineroom. Sometimes, there is another breaker under the deck in the bow. To drop an anchor without power, insert the winch handle in the top of the windlass and loosen the clutch until the anchor freefalls. Make sure the windlass works first, or risk cranking the anchor up by hand with that same winch handle.

11. Understanding Electrical Systems

If dock breakers are on but the boat doesn’t have power, check breakers required within a few feet of where shore cords enter the boat. These can be particularly problematic when dock power drops below 220 volts. Boats with two shore cords split main panels into two sections. Meters show the amperage draw, which can’t exceed 50 on either panel without tripping that cord’s breaker. Some dock breakers won’t hold 50 on a hot day. Single 100-amp cords power the whole boat, but the panel is still usually split. One side can pull 90 amps or more, and the other 10, as long as the two don’t exceed 100. Turn off running equipment on the offending panel to lower amperage draw, or fire up a generator. One 20kW generator will carry 80 amps, and can power one side of the electrical panel while a shore cord powers the other.

12. Fire Safety Tips

Don’t open the engineroom door-a fire will reignite. Turn off all AC and DC power and fuel valves that you can access, and find the captain of a large yacht, required by international treaty to attend shipboard firefighting school every five years.


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