Engine on/off

[Guest]

Another serious question. If cruising in slow waters or river is there any advantages of running on single engine (if you have twins) regarding saving fuel etc . or is it negligible compared with loss of manouvrability and higher revving engine.

 

[ToMo]

Going back to the days when I had serious boats, in one case (Grand Banks42) it was an advantage regarding fuel saving, in the other case an ex RAF pinnace it didn't seem to make much difference on the fuel usage at all, in both cases there was some loss of controlablility; I think it's a question of suck it and see!
TôMö

 

[byron]

Apart from the dubious act of dragging an unfeathered prop through the water thus rotating a dry engine and gearbox. I wonder about the insurance aspect.
Could it be argued by an Insurance Company that by running on one engine you do not have full control of your vessel and in the event of an incident they could use that against you and void your claim - just a thought.

ô¿ô

 

[hlb]

It's all come up before Mark. But then just about everything has come up before. There's pros and cons. May be depends how busy the river is. If wide and not much hapening. I sometimes turn one off. just to reduce noise, but then have to turn it back on again before too long. My auto pilot has severly reduced rudder movement so one engined stuff is nearly imposible unless, the whole English channel used for turning circle.

Haydn

 

[Guest]

I have often used the Crinan canal to reach the West coast of Scotland from the Clyde. In my last boat which had twin TAMD41a's, tickover on both was faster than the canal's speed limit so I regularly used one engine but

a) The redundant engine should be kept in gear to lock the prop and prevent windmilling which can damage certain types of gearbox if prolonged
b) Key for second engine was kept in ignition and both engines were used for maneuvering in locks, etc.

About 1000rpm on one engine gave 4knts and the steering was perfectly adequate once the offset to determine straight ahead was determined.

Nick

 

[oldsaltoz]

Just another point to consider.
Running your diesel engine at idle or low rev’s for prolonged periods can cause damage by glazing the cylinders, so it may be an advantage (in some cases) to run only one.

Old Salt Oz.

 

[Piers]

Another thought to do with autopilots.

Often, power assist for steering is from one of the engines, only. Hence, driving when that engine's off increases the force the helm requires. If you have an autopilot which depends on the power assist, you can do the pilot's drive unit a great deal of harm.

Piers du Pre
MBM Cruising Club enthusiast
www.dupre.co.uk

 

[tcm]

Re: nick, byron

That means (if have twin morse for twin engines) push forward the switched-off engines, yes? It doesn't need "shaft locks" whatever they are?

INcidetally, re byron's insurance concern tho valid, really that we MUST have both engine on, cannit that be a clause? Else what bout hitting things and they say aha didn't have the radar on? Think skipper decides what "control" looks like, and if "control" is one engine off to save it for er being fresh and ready whilst at sea and (aha!) not being gunked up soot due to slow running, that's surely okay, no? Prob not the same with big ships, where radar shd be on, differet standards and so on?

 

[boatone]

If one had an accident which could reasonably be attributed to not using BOTH engines IF fitted AND in working order then you might be deemed guilty of contributory negligence in not using all means at your disposal to avoid loss. Similarly, if radar fitted and not used in circumstances where reasonable care would indicate that it should have been in use.
My limited experience of using one engine only where two fitted is that subject to getting a feel for the slight steering offset needed (and opposite rotational effects) it is little different to being in a single engined craft. On inland waterways there is the undoubted advantage of being able to run the engine closer to optimum performance/economy at low speed.

TonyR
boatone@boatsontheweb.com

 

[Guest]

Re: Shaft locks and insurance

a) Shaftlocks are probably required if youwere say going to do a long passage at 8 knots on one engine. The situation I describe is on a BW canal where the speed limit is 4 knots. At this speed having the unused engine in gear (using my morse controls as you point out) was not a problem as the speed was insufficient to turn the engine against compression. I dare say going faster would but on a canal this is not a problem.

b) As far as insurance goes, I believe I had the boat under control at all times. On my Birchwood steering on one engine was not a problem except for the tightest of turns, when you would start the other engine anyway. I suspect your insurance would be more at risk if something happened whilst exceeding the speed limit in confined waters e.g. a canal.

Finally, one engine running at something more than tickover is better than pottering along at tickover all day. However, for lengthy canal work, a naturally aspirated diesel is better and I wonder about the problems people have with high speed turbo charged diesels taking them for a lengthy sojourn through the European canals as lots of people seem to do.

Nick