Maintenance tips from River Canal Rescue

Published: Wednesday, 30 October 2019

IN A BID to reduce the number of incidents on our waterways, River Canal Rescue (RCR) shares the
main causes of this year’s call-outs and offers some maintenance tips.

These will perhaps help boaters enjoy stress-free cruising in 2020.

Over 100 call-outs a week

During 2019, RCR on average attended 105 call-outs a week (covered by its membership service). Of these, 18 per week were for major rescues and repairs, chargeable outside membership, the remainder were classed as minor.

Minor is defined as situations which on attendance, can be resolved (within two to three hours) without the need for a full rescue team. Major is defined as submerged, partially sunken or grounded craft, plus salvage work (engineers typically spend a day on each call-out).

Minor call-outs

Minor call-outs were primarily due to fuel, alternator, electrical, battery, cable, cooling system, gearbox, starter and propeller problems., that included:

♦ Gearbox, propeller, drive plate, coupling, prop shaft, engine mount, hull and rudder damage,
due to hitting underwater objects or locks

Loss of propellers and nuts/rudders coming away

Domestic water ingress due to a lack of bilge pumps

Engine electrics catching fire.

Maintenance tips

RCR Managing Director, Stephanie Horton, explains:

Fuel problems are mainly caused by diesel bug and contaminated water. Diesel bug is an enzyme that lives off water in the diesel, either appearing as black dust soot or a black slime/jelly.  Once in the system it clogs the engine’s fuel arteries and stops the engine working.

Mild cases will respond to a fluid ‘Marine 16’; it prevents bacterial growth and kills anything that may be forming in the tank.  More severe cases require a diesel bug shock treatment.  Dirt and debris can also block filters and contaminate fuel so check and service regularly.

Electrical issues

Alternators operate in a damp, hot environment which is not good for electrics . If the bilges are full of oil and water when the engine’s running, it will be thrown over the engine, hitting the electrical components.  If left for a long period of time, rust can also develop and affect their operation, so it’s important to check the bilges and run the engine frequently.

Electrical issues are usually due to overlooked connections.  Check for corrosion, wires coming away, loose connections or disconnected wires before starting a journey and use a water resistant spray or petroleum jelly to stop damp getting into isolators and block connectors.

The right batteries

Starter systems must have the right batteries.  A cranking battery delivers a high output quickly while a leisure battery delivers a lower continuous output, so needs regular charging to maintain capacity.  If in a good condition, each battery in a bank generally requires two to three hours charging as a minimum to keep them topped up and will require more if discharged.

Each battery cell can affect the whole battery bank so to prevent deterioration, regularly check and top up the cells’ water levels with de-ionised water.  If one cell’s water level drops to below 50% it will bring the battery bank capacity down to the same level, irrespective of how good the other batteries are.  Never mix batteries and always replace a whole bank of old with new.


As most of the cable terminus is set outside, if not used regularly, cables will rust.  To prevent this, grease the end of the cable, particularly if leaving the boat for a long period of time, and when setting off, check for any roughness or stiffness. If fitting new cables, keep bends to a minimum (they’ll suffer higher stress and so may fail in the future).

Overheating is usually due to an air lock in the cooling system.  To identify this, feel the top and bottom of the swim tank—there should be a difference in temperature. If not, find and unscrew the bolt sitting on top of the swim tank.  This releases the air locked in the system.   Overheating can also be caused by a coolant hose rupturing, a water pump failing, a fan belt shredding or at its worst, a head gasket failing.

Gear box and drive plate failure

General wear and tear is the main cause of gear box and drive plate failure, so regularly service the gear box.  When hitting an underwater object, it may affect the drive plate, but not necessarily the gear box.  With a fouled propeller, loss of propulsion is commonly due to the prop being covered in debris such as weed or leaves. Clear by putting the engine into reverse.

Prevent water ingress by keeping an eye on water levels within a craft and installing an automatic bilge pump. When there are stormy weather conditions and periods of heavy rain, water can seep into a boat, build-up and if not addressed, cause it to sink.