To warm up or not to warm up?

[Avocet]

My small single cylinder diesel doesn't take long to warm up anyway so this isn't that relevant to me but it struck me that this engine is a marinised derivative of a stationary cement mixer / generator engine. That means they often run at constant high speed as soon as they are started - even in much colder weather than one would routinely find in the engine compartment of a salt-water dwelling boat!

I'm told that this was one of the biggest problems facing the designers of the old (petrol) Coventry Climax engine - as it was first used in fire pumps so had to go from cold to 5000RPM instantly. Apparently they suffered a lot of cold seizures on the development ones!

 

[andy_wilson]

In your case I would have thought that if all is prepared for departure except warps, that is the time to start the engine.

After checking all is normal by sight, sound and on the dials etc., by the time you have cast off, the engines will be warm enough and be fine for light loads to leave the confines of the marina.

Once outside, a last check of the dials should confirm temps. and pressures are ready for anything up to and including full load application.

It is a generally accepted fact that 95% of engine wear occurs in the first minute following a cold start. After that you would struggle to do any great harm unless you insisted in 'gunning it' whilst still quite cold, which would be hard to do from a marina berth and a challenge from the anchor unless in very open water.

A long period under idle is counterproductive. Marine engines are way over cooled at low loads, and a brisk warm-up is preferable to a protracted one.