Bird’s Nest Soup
Rivers and canals are delightful, leafy places, often with languid shallow waters. Even if the water is not that languid, it will contain mud, silt, twigs, leaves – all sorts of particles that can clog up your engine cooling water intake, supply pipe or filter. This is a hazard when travelling along; it becomes worse when passing through locks because there the languid soup boils up and whatever was lying peacefully at the bottom or at the surface gets properly mixed in, at a time when you will be using the engine – in forward and reverse gears – critically.
Not surprisingly, engine cooling problems – blockages – occur most often during and immediately after, locking. [Except of course, for the obvious actually running into some shallow patch of mud]. The engine cooling alarm shrills away and immediate turning-off (to prevent serious damage through overheating) is called-for, with consequent loss of power and control. The first time this happened we were mid-Seine – we turned off, looked around for a ‘refuge’ to moor to, saw two peniches bankside, drifted in their general direction as much as we could, then switched on for as short a time as possible whilst we got into position and tied-up.
Backwash, Check and Clean
Through necessity we discovered the remedy. Use a hand or foot pump, via the filter bowl inlet hole, to backwash the boue out of the pipe and the inlet. The dinghy footpump works extremely well for this purpose – we keep it conveniently to hand, with the appropriate adaptor already plugged into its hose. We also learned that checking and cleaning the filter basket at setting-off, at midday lunchbreaks, and after having arrived was a necessity. The stuff that gets pulled in and trapped there is amazing. Whilst we were moored next to a big Finnish motor cruiser, they cleaned their twin filters and inspected their (to us) giant-sized pump impeller. The pile of twigs that came out of the filters looked like a bird’s nest. There were only two vanes left on the impeller.
Lock in, Tie up, Turn off
On the Midi the situation is far worse than anywhere else we’ve been – the overheating alarm problem occurred three days running. We have adopted a preventative strategy that consists of checking, cleaning and backwashing whenever we stop, and stopping to do that when appropriate. We also turn the engine off in locks – after having set our lines, etc. This is what the VNF say you should do, but we’ve never yet seen anyone do it. Except now, us.