Issues At Sea

Regular maintenance of engines and following service schedules are of paramount importance on any craft, wherever you sail.  When you head out to sea it’s even more important as a breakdown may well not just endanger your own life but risk the lives of your rescuers.

Planning the trip Voyage planning is basically common sense.  As a pleasure boat user, in particular, you should take into account the following points when planning a boat trip:-

  1. Weather – Check the weather forecast and get regular updates if you are planning to be out for any length of time.
  2. Tides – Check the tidal predictions for your trip and ensure that they fit with what you are planning to do.
  3. Vessel Limitations – Consider whether your boat is up to the proposed trip and that you have sufficient safety equipment and stores with you.
  4. Crew – Consider the experience and physical ability of your crew.
  5. Navigational Dangers – Familiarise yourself with any possible navigational dangers.
  6. Contingency Plan – Always have one in case anything should go wrong.
  7. Information Ashore – Ensure that someone ashore knows your plans and knows what to do should they become concerned.
  8. Spares – Keep essential spares on board – impeller, oil and fuel filters, fan belt and a few tools to change the items.

A twin engine boat generally has the luxury of being able to get back to shore but this is not always the case.  Obviously a craft with single engine failure can have serious consequences.


Engine Overheating Is water coming out of the exhaust?  If the answer is no, then,

  • Check intake filter and clean (turn the seacock off first).
  • Check the impeller.  If failed ensure all broken parts are found, possibly further along the pipe run and change.

If the answer is yes, then,

  • Check for belt tightness (If the alternator warning light is on, the belt may be slipping).  Adjust or change if necessary.
  • Check there is water in the heat exchanger  (or expansion tank) – by removing radiator cap when cooled (beware of pressure and potential scalding water) – top up with warm water if necessary ..
  • Check all intake/engines hose connections – tighten as necessary.

Other potential causes for overheating include:- faulty thermostat, clogged/scaled tube stack, cyclinder head gasket, cylinder head cracked.

Engine Loses Power or Cuts Out There are numerous reasons for this but it is commonly associated with a fuel issue, for example:-

  • Blocked fuel filter.  Change if necessary.
  • Contaminated fuel.  Clean tanks and treat with chemicals.  Change filters.
  • Dirty fuel.  May be necessary to change fuel filter 2-3 times.
  • Air getting sucked into fuel lines.  Re-tighten all joints and be aware air can be sucked in but not necessarily leak fuel.

Electrical Failure A failed battery and bad earth connections are the most common of electrical issues causing an engine not to start.  Ensure that the heavy main battery cables are secure on the batteries and battery switches and the negative (paint or corrosion at this point will cause a voltage drop).

A simple digital voltmeter is a very useful piece of equipment to keep on board.

In general terms – 12.7v – 12.8v is a fully charged battery (should show 14.4v with engine running fitted with standard alternator 14.7 with certain external controllers).   A battery reading below 12.2 will not normally start an engine.