Select Page

Providing they are regularly serviced and maintained, modern marine diesel engines tend to be very reliable. However, they are by no means infallible and a large percentage of lifeboat rescues are to leisure vessels with engine failure. Fortunately, a handful of easily rectified problems are responsible for a high percentage of engine failures. These can normally be fixed in a few minutes with a relatively small amount of knowledge, a few simple tools and by carrying a small number of inexpensive spares.

Many engine failures are caused by lack of maintenance, resulting in fuel filter blockages, water pump failures, overheating and other breakdowns. Indeed, one of the most common reasons for marine rescue service call outs is for one of the most basic reasons possible – boats that have run out of fuel. One of the golden rules is to always check the fuel tank levels before setting out and to carry reserve fuel in case it is needed.

engine failure at sea

Another common situation is one in which sediment that would otherwise sit (apparently harmlessly) on the bottom of the fuel tank is shaken around in a rough sea and then sucked into the fuel system, blocking the filters. It’s also possible for bacteria that will eventually clog fuel filters to form in diesel tanks, although again effective maintenance will minimise the risk of this.

Engine failure – when the alarms buzz

To prevent the risk of serious damage, immediate action must be taken if an engine alarm sounds, even if the motor continues to operate. Take the engine out of gear and check which warning light is lit up, with the motor idling in neutral.

The engine should then be shut down while you attempt to fix the problem. Note that, although there are warning lights for low oil pressure, overheating and lack of battery charging, on most engines an alarm will not sound for the latter fault.

boat primary filter

The rationale behind this is that it’s not a problem that must be immediately dealt with to avoid damage to the engine, although of course it could result in the batteries running flat within a relatively short length of time.

boat fuel filter

If your engine fails or is overheating there are a number of things to check immediately:

  • Air filter blocked – check, clean or replace.
  • Cooling water low – fill when engine is cold. Check for leaking hoses.
  • Exhaust pipe blocked or partially blocked.
  • Fuel filter – a blockage reduces power and can stop the engine. Check, clean or change the filter.
  • Lack of lubrication – check engine and gearbox oil levels.
  • Oil filter blocked – replace.
  • Raw water inlet filter – a blockage causes overheating and can lead to engine failure. Close seacock, check and clear filter. Re-open seacock. Check object (eg. plastic bag) is not obstructing seacock.
  • Water pump impeller failure – cooling system fails and engine overheats. Check the rubber impeller is slightly flexible, not hard, and that all the vanes are intact. Replace if necessary.
  • Worn alternator or water pump drive belts – replace if they are frayed or shiny.

boat impellor

Tips to avoid engine failure:

  • Keep the engine regularly maintained.
  • Always do engine checks before setting out.
  • Check fuel and oil levels regularly (don’t rely on gauges!).
  • Check drive belts for wear and tightness.
  • Look out for oil and coolant leaks.
  • Check fuel filter for water or dirt. Drain off any contaminants until the fuel in the clear glass bowl by the filter is clear.
  • Learn how to bleed the fuel system if air gets into it.

Happy boating and stay safe on the water!

Antifouling for leisure boats – Part 1

Boats that are kept afloat can very quickly become a home for small marine organisms such as barnacles, weed and slime. Applying an antifouling paint to your hull is necessary to protect it from these micro-organisms, as a fouled hull can cause problems and will slow down a boat’s maximum speed considerably if left unchecked.

Sending distress signals

In an emergency situation at sea, it is a top priority is to know how to send and receive emergency radio calls and alert others of your predicament. Likewise, if you receive a distress signal, you must be ready to go to the help of others.

ColRegs when sailing single handed

  Don’t neglect the Colregs when sailing single handed Sailing single-handed represents several challenges for skippers, not least how to...

Rewiring a boat – overcoming the challenges involved

Skippers need to have a basic knowledge of boat electrics, to avoid potential problems and to be able to solve them when they happen.

Essential Knots: Figure of eight

Essential Knots: Figure of eight Use: Stopper knot, prevents a rope from being pulled through a hole e.g. through a block or...

Peer to Peer yacht charter – How can you monetize your boat?

There is a growing trend in peer to peer yacht charter. How does it work? People already rent rooms, cars and bikes from one...

Understanding tides

If you are used to sailing in tidal waters, you will know that tides can be both a benefit and a hindrance to the sailor. In many ways,...

Top 5 Reasons Why an Inflatable SUP Should Be Your Next Yacht Accessory

In this article, inflatable paddle board expert Jason Paul gives the top 5 reasons why an inflatable SUP should be your next...

VHF DSC radio – how best to communicate at sea

There are many ways to communicate with others at sea. What makes the VHF DSC radio the best form of short range...

Boating emergency – how to broadcast a MAYDAY emergency call

How to broadcast a MAYDAY emergency call   How to broadcast a MAYDAY emergency call if a vessel or person is in grave...

How to improve a yacht’s upwind performance

There are several ways to improve the upwind performance of a sailing yacht. Read on for some useful tips including headsail reefing, heavy weather jibs and motor sailing.

How to operate a winch

Winches are drum shaped mechanical devices used to handle halyards, sheets and control lines. One of the important crew...

Seized fixings and fastenings

Maintaining a boat can be a rewarding experience but at times it can also be frustrating. A prime example of this is when you come across a seized fixing or fastening that refuses to budge. Read our tips on how to release and fix them:

Wooden Hulls – Part 2

It is important to ensure the essential hull maintenance of a wooden boat is done, even if you are paying others to look after your boat for you. The priority is to prevent rot from taking hold. The protective layers of paint and varnish over wood are far more critical than on GRP boats, where the topsides are painted more for cosmetic reasons.

Preparing for sailboat cruising

Preparing for a sailing trip entails a lot of planning. In this blog, we take a look at some of the many safety aspects that a skipper needs to consider before heading off on a cruise.

Tools and spares for your boat

It is wise to have a comprehensive and well-organised tool kit and a supply of spares for your boat. This is both for routine...

Boat surveys

A full boat survey assesses the condition of the hull, mechanical gear and means of propulsion. The survey is carried out with the boat...

A simple guide to understanding tides when passage planning

Understanding tides when passage planning When planning a trip in tidal waters, check the tides before going afloat. Use...

Competent crew skills: mooring lines

Mooring lines are used when arriving or leaving a berth. One of the most important competent crew skills is to know how to...

Marine engine electrical system

The typical basic electrical system associated with a marine engine includes a dedicated engine starting battery, a starter motor, a charger in the form of an alternator, a solenoid and some engine sensors and instruments.

Rudders and steering systems – Part 2

One thing all rudders have in common is that they have three main parts that need to be checked: the rudder, or a steerable drive leg in the case of many power boats; the system that joins the rudder to the steering; the steering control itself.

Nautical paper charts – a reminder of the basics

The nautical chart is an indispensable tool for navigation. A chart is a graphic representation of an area of the sea which might also include coastlines, estuaries and islands. All cruising leisure boats should carry up-to-date paper charts.

Boat Handling – anchoring

Anchoring your yacht or motorboat Anchoring is one of the most important boat handling skills. If you can set an anchor...

Boatyard Health and Safety

Boat storage facilities are potentially hazardous environments and it is the responsibility of both boat owners and boatyards to ensure that the...

Keel design – options to consider when choosing a yacht

Keel design is constantly evolving and nowhere is this more apparent than in modern racing yachts such as the Imoca Open 60...