A charter yacht is a small house with an engine, and on a flotilla the lead crew's engineer is a radio call away. Your part is the daily check, reading the alarms correctly and stopping a small fault before it becomes a big one.
What should I check on a yacht's diesel engine every morning before starting it?
The daily check, two minutes in the engine box: oil on the dipstick, coolant in the header tank, drive belt tight and not frayed, raw-water strainer clear and seacock open, bilge dry, fuel tap on with fuel for the day.
Every morning, before the first start, open the engine box and look. It takes two minutes and finds most problems while you are still tied up.
Yacht engines are diesels. Petrol in the tank means draining it, with a fire risk and a damaged engine: at the fuel quay, look at the nozzle yourself. Work out the fuel for a leg before you go: hours under engine times litres an hour, with a reserve left over.
20 M ÷ 5 kn = 4 hours. 4 h × 3 L/h = 12 litres, so 48 of the 60 are left.
No water is coming out of my boat's exhaust: what should I do?
Stop the engine: no water means no cooling. Check that the seacock is open and the raw-water strainer clear; if the intake is clear and still no water comes, the impeller has failed, so call the lead crew.
The engine is cooled by sea water. It comes in through a seacock, passes the raw-water strainer, is pushed along by a pump with a rubber impeller and leaves with the exhaust. So after every start, look over the stern: water must spurt out with the exhaust. No water means no cooling, and you stop the engine.
| No water: check | What you do |
|---|---|
| Seacock | Make sure it is open |
| Strainer | Weed or plastic in the bowl: clean it |
| Impeller | Intake clear and still no water: the impeller has failed. Stop and call the lead crew |
Close the seacock before you open the strainer, or the sea pours in. Open it again before you start, or the engine overheats.
What do I do when the low oil pressure alarm comes on under engine?
Stop the engine: low oil pressure can wreck a diesel within minutes. Check the oil level and do not restart until you know why. Only close to a rocky lee shore do you unroll the genoa and sail clear first.
Both alarms ask for the same first action: stop the engine. Overheating with steam and little water at the exhaust means the raw-water flow has failed: check the intake. Low oil pressure can wreck a diesel within minutes: stop, check the oil level, and do not restart until you know why.
The one exception is the safety of the boat. Close to a rocky lee shore, unroll the genoa and sail clear first, then stop the engine.
A thump under the stern, heavy vibration and lost speed near fishing floats mean a rope round the propeller: go to neutral and stop the engine.
How do I stop the fridge flattening my engine battery overnight at anchor?
Run everything from the house bank and keep the engine battery isolated. With the switch on BOTH the two banks are joined, and a night of fridge flattens the starting battery as well.
The boat has two battery banks. The house bank runs the fridge, lights and instruments; the engine battery only starts the engine. At anchor run everything from the house bank and keep the engine battery isolated. With the switch on BOTH the two are joined, and a night of fridge flattens the starting battery as well.
| Volts at rest | State |
|---|---|
| 12.6–12.7 | Full |
| About 12.2 | Half: time to charge |
| Under 12 | Flat |
Batteries charge from the engine's alternator or from the shore-power charger. A charge light that stays on with the engine running, and a squeal from the engine box, point to a slack or broken alternator belt. On many engines the same belt drives the water pump, so watch the temperature too.
For shore power, plug the cable into the boat first and the pillar second, so you never hold a live loose end. To leave, unplug at the pillar first.
In what order do I turn off the gas on a boat after cooking?
Shut the supply first, at the solenoid switch or the bottle valve, let the flame burn off the gas left in the pipe, then turn off the burner knob. Gas is heavier than air: a leak sinks into the bilge.
Cooking gas is heavier than air. A leak does not blow away: it sinks into the bilge and lies there until a spark finds it. So gas is in the pipe only while you cook.
After cooking, shut the supply first, at the solenoid switch or the bottle valve, and let the flame burn off the gas left in the pipe. Then turn off the burner knob.
Supply off, flame dies, then the burner knob.
The bilge is filling but the electric bilge pump is silent: what do I do?
Pump by hand with the manual bilge pump, then check for a blown fuse or a stuck float switch. Find that pump and its handle on the first day: it works when the electrics do not.
| What you notice | What it means | What you do |
|---|---|---|
| The water pump runs on, the taps spit air | The tank is empty | Pump off, switch to the other tank |
| You are in harbour or at anchor | The heads must not pump overboard | Use the holding tank; empty it at a pump-out, or offshore where local rules allow |
| The bilge is filling, the electric pump is silent | A blown fuse or a stuck float switch | Pump by hand, then check both |
A water pump left running dry can burn out, so switch it off at the panel as soon as the taps spit air.
Find the manual bilge pump and its handle on the first day. It works when the electrics do not.
Questions from this topic, as the app asks them. Open one to see the answer.
How much fuel will be left when you arrive?
D. 30 litres — well above the reserve
30 M ÷ 6 kn = 5 h; 5 h × 4 L/h = 20 L used; 50 − 20 = 30 L left.
You are going to clean the strainer. What is the right order?
C. Close the seacock, clean the strainer, open the seacock
Close the seacock first or the sea pours in; reopen it before starting or the engine overheats again.
You are motoring in open water, well clear of other boats, when this happens. What do you do?
A. Stop the engine, then check the cooling water intake
Overheating with little exhaust water means the raw-water flow has failed: stop before the engine is damaged.
You are settling in for the evening at anchor. Which battery do you run the boat from?
D. The house battery, keeping the engine one for starting
Domestic loads run from the house bank; the engine battery stays isolated so you can always start.
Your crew has finished cooking pasta. How do they turn off the gas?
A. Solenoid off, let the flame die, then the burner knob
Shutting the supply first lets the flame burn off the gas left in the pipe, so none sits in the line.
Your crew is in the shower when this happens. What is wrong?
C. Tank 1 is empty — switch off the pump, change tanks
A pump that runs on while the taps spit air has emptied its tank; a pump running dry can burn out.
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