This page is about the first half hour when something goes wrong aboard. The aim is not for you to repair the fault; it is for you to define the problem correctly, avoid making it worse, and give a useful description to whoever you call.
The order of priority never changes: 1) People · 2) Keeping her afloat · 3) Fire · 4) Ability to manoeuvre · 5) Everything else.
1. Taking Water
- 1Peoplelifejackets call for help
- 2Stay afloatingress pump · plugs
- 3Fireshut off · keep the hatch closed
- 4Manoeuvreengine · steering close the coast
- 5The resteverything else
First minutes
- Lifejackets on. Assess how close you are to shore and to help.
- Check the bilge pump is running; get the manual pump ready.
- Where is it coming from?, salt or fresh (you can taste it), warm or cold (engine circuit?).
- Check in order: shaft seal, seacocks and hose clamps, rudder stock, exhaust line, strainer lid, raw water pump, calorifier and fresh water lines.
The usual sources
| Source | Sign | First action |
|---|---|---|
| Shaft seal | Continuous flow around the shaft | Adjust the gland nut on a traditional stuffing box; over-tightening causes heat |
| Hose or clamp | Wetness above the valve | Close the seacock, which is why every one must be reachable |
| Seacock body | Leaking from the valve itself | Ready a tapered plug (every boat should carry a set) |
| Strainer lid | Dripping around the strainer | Check the seal, seat the lid properly |
| Exhaust line / waterlock | Flow increases when the engine runs | Stop the engine; inspect the line |
| Rudder stock seal | Water in the aft compartment | Seal and bearing check; usually a job ashore |
The critical point: if the ingress exceeds the pump, the priority is not plugging the hole, it is calling for help and closing the coast. Every boat should carry a set of tapered wooden plugs, a working manual pump and a bilge alarm.
2. The Engine Is Overheating
- Reduce revs; stop the engine if needed. Pushing a hot engine causes irreversible damage within minutes.
- Is water coming from the exhaust? If not, the raw water circuit has stopped, that is the most urgent case.
- Check the strainer: weed, a plastic bag, marine growth.
- Impeller: if a vane has broken off, the pieces collect in the heat exchanger; when fitting a new one, account for the missing vanes.
- Check belt tension and coolant level.
- Thermostat and a scaled heat exchanger: usually resolved ashore.
The great majority of overheating has nothing to do with the engine itself and everything to do with the cooling circuit. Overheating alone is not a reason for an overhaul.
3. Batteries Flat / Not Charging
| Sign | Likely cause | Check |
|---|---|---|
| Starter will not turn in the morning | Start battery weak, or paralleled with the service bank | Is the split charge relay or isolator working |
| Low charge indication while running | Alternator, belt or regulator | Belt tension; voltage at the battery terminals while running |
| Bank drains quickly | Lost capacity (age or sulphation), or a hidden draw | Measure current with the main isolator off |
| Charger will not fill them | Charge profile wrong for the battery type | Gel / AGM / flooded setting |
| A battery is hot or swollen | Overcharging, dangerous | Disconnect charging immediately; check the regulator |
Batteries are replaced as a bank. Putting one new battery into an old bank pulls the new one down to the level of the old within months.
4. Vibration Has Started
- Rising with revs: propeller (fouling, blade damage), shaft alignment or the cutless bearing.
- Peaking at one particular speed: resonance; usually mounts or the shaft line.
- Started suddenly: something around the propeller, line, netting, a bag. Nobody goes in the water until the engine is stopped and the shaft locked.
- Ignored vibration accelerates bearing, seal and gland wear; a cheap problem becomes an expensive one.
5. Fire and Smoke
- Stop the engine, shut off fuel and gas, open the main isolator.
- Do not open the engine space hatch, giving it air feeds the fire. Use the extinguisher port if one is fitted.
- If an automatic system is installed, allow it to discharge.
- Everyone on deck, lifejackets on, call for help.
The two most common sources of fire aboard are the electrical installation (loose connections, undersized cable, unprotected circuits) and fuel leakage. Both are among the most frequently recorded items in a survey.
6. I Have Run Aground
- People first: injuries, ingress.
- Do not immediately drive the engine hard, you will draw sand and silt into the cooling circuit.
- Check for underwater damage and the bilge.
- After recovery, do not continue the passage until she has been lifted and examined: keel attachment, rudder, shaft alignment and laminate.
- Notify the insurer within the policy period; photograph the damage as it is.
Survey after a grounding: even where nothing shows, there can be effects at the keel root and in the internal structure. It is one of the most frequently requested items, both for an insurance file and for a future sale.
7. What Every Boat Should Carry
- A set of tapered wooden plugs sized to every seacock
- A working manual pump and a bucket
- A bilge alarm, independent of the pump
- Spare impeller, belt and hose clamps
- Fire extinguishers in date, and an automatic system for the engine space
- A main isolator within reach
- Basic tools and a clamp set
Frequently Asked Questions
First establish whether it is salt or fresh, warm or cold. That halves the search. Then work through the shaft seal, seacocks and clamps, strainer, exhaust line and rudder stock. If the ingress exceeds the pump, call for help before anything else.
No. Pushing a hot engine causes permanent damage within minutes. Reduce revs, stop, and check for water at the exhaust, if there is none, the raw water circuit has stopped.
As a bank. One new battery in an old bank is pulled down to the level of the old ones within months.
Yes. There can be effects at the keel root, in the internal structure and in shaft alignment even when nothing shows. A measured record serves both the insurance file and any future sale.
Never with the engine running and the shaft unlocked. If in doubt, call a diver. Afterwards the shaft and seal should be checked.
No. In an emergency call the official search and rescue service and your marina first. This page is to help you describe the problem correctly in the first half hour.
Related Pages
Safety EquipmentDates and accessibilitySafety EquipmentService dates and checksGas Systems (LPG)Locker, hose, detectorGood SeamanshipHabits that prevent itLithium Battery ConversionRenewing the battery systemRepair Guide100 findings and correct repairMarine Engine OverhaulOverheating, smoke and the decisionSea Trial ChecklistWhat is watched under loadYacht InsuranceWhat to do when damage happensCommon Boat DefectsThe twenty recorded mostMarine Survey GlossaryWhat the terms mean
Let us define the problem together
Describe the symptoms; we will work out what to check and who to call.
💬 WhatsApp 📝 Written quote 📞 +90 501 5 SURVEY