Do we use one engine or two?

B

Bluemac

Well-Known Member
Joined
24 Jun 2004
Messages
101
Location
Mid Sussex
Visit site
Hi gang! When SWMBO and I bought our boat, the 'pipe dream' was that one day we will take her through the French canals and into the Med (like sami_lymington only slower!). We have done several French canal holidays with hire boats, but they only had one engine. Now we have one with two diesels I ponder whether people travelling the canals use them both at very low revs, or use them one at a time in rotation, to keep the engine hours roughly equal? Is there an accepted norm, and would the latter method be more economical that the former? I've tried to find reference to this query in books and articles, and so far failed spectacularly!

I'd really value your opinion.
 
definetley use one at a time assuming you are running at a middle to low revs, but really is a question answered more accurately by looking at fuel useage per revs, and revs needed for specific boat speed.
 
Hi Ron I always used to use both engines on my boat on the Thames, at tick over they burn minimum fuel.

Disadvantages of using one: correcting helm a lot with small rudders, dragging prop anyway, turn on second engine when coming into locks anyway. All IMHO of course Clive
 
some thoughts on one or two

advantages of running on one

1 saves a small quantity of fuel

2 lessens the chance of bore glazing as on engine has to work a little more


Disadvantages

1 often difficult to steer

2 wear on steering system as many more steering inputs required

3 have to start up for control to pass barges, bridges, locks other yachts etc etc

4 what if engine wont start for item 3

5 lubrication of trailed shaft gearbox bearings / plates

6 added load to charging system for starts & one engine now has to replace service battery charge for fridge & night load & run fans etc from the day load.

7 raises engine room air temp from heat soak of stopped engine

8 raised alternator temps from 7 (experienced this leading to early diode and winding failure)


As you see I am not a great lover of one engine running as it saves a fiver and might costs hundreds
 
I always use two ! unless one is not fit to run !

You also have to look at which engine powers what?

Power steering? Calorifier? does engine return fuel to which tank?

You are the one that will decide at the end of the day, so why not try out and see?

Tom
 
Dont understand your point 7 David? Surely engine room cooler if only one motor running. /forums/images/graemlins/confused.gif
 
I'd definitely go for one engine for as much of the time as poss. But if you have power steering it will be powered by one engine only, so that engine has to be the one running.

Hot water also will be off one engine. Possibly even your domestic batteries.
 
When both engines have been running , then one is stopped, engine room air temp increases rapidly as the stopped one cools, unless there are v large vents / fans running, until the stopped one temp falls to near the engine room air temp.
 
In the words of the song - 'there are more questions than answers, and the more I find out the less I know'!! Thanks for all your responses so far - keep 'em coming. In the meantime I'll start to try to find out which engine drives what, etc. etc. !!
 
Previous boat had twins,did hundreds of miles in holland belgium and france,used engine for calorifier,then when warm used other,tended to change every hour or so.on flowing rivers ie dutch rhine always used both.If your on a canal thats shallow use the one away from bank.On tidal rivers use both.most g/boxes are ok for freewheeling but check.
 
I think its better to toggle between engine to engine as useing both, you use less revs and turbos on engine sout up easy plus if you dont have outdrives you may not have power steering off engines but have hyd steering which is idepenent from engines anyway. Just make sure your keeping your batterys charged up on both port and stb side. Thats my input on this.
TIP: - If your boat has trim tabs why not use them to counter act the use of one engine against your stering? i.e if your useing port engine the boat will vier to stb so why not drop down port tab to pull the boat back? may use a egg cup more fuel but save the arms!!
 
Hi
I used 1 engine most of the time on the canals except for manovering in and out of locks
The main reason was that the speed limit is 6km per hour I did around 5-6 knts per hour and to keep both engines on created a lot more wake because both props are turning
Reason 2 was that you were only just on tickover with both engines on and my diesel engineer told me it was better to have one engine doing 2200 rpm rather than have 2 doing 1000 rpm and coking up
The canals are very very slow because of the hugh number of locks and the fact a lot of the lock keepers close down for lunch 12.00 --1.00 pm
Facilities are fairly scarce and you have to like lots and lots and lots of country side its the sort of thing I think I will do a bit more maybe when I retire but then maybe not
The actual med knocks the spots off the canals swimming every day cracking beaches and the freedom to go anyway you want without feeling the control of lock keepers
But I must say they do actually open all the locks for you
 
But on most boats all the engine room fans would be running whether one or two engines are running. I think so at least, and that's how ours are wired. In which case, the engine room will start to cool as soon as one engine is turned off.

If however half the engine room vent fans turn off when you turn one engine off, then I'd agree with you
 
some highly experienced riverish people came with us and said you shld use just one engine the other running in neutral else it can [no thanks] gbox or other stuff . The "glazing" is a bit of a myth short-term as either running a bit or in neutral is same diference and a glaze wd only hit on years of idling, not a little bit.
 
Would only run on one engine if you can't keep below speed limit with two, if not would run both at minimum revs, tends to make the boat easier to control, and you have both engines available immediately if you need them.
 
That is how I think commercial vessels always operate and I suspect that they know the most economical way (unless four engined with water jets when an engine each side may be run with the other two shut down).

Was also recently an article (from a normally correct author) in a local mag here in NZ that maintained that operating on just one of two propped engines is less fuel efficient than operating on two due to the increased resistance from prop and steering correction.

John
 
yup glazing takes years my Broom was used on the Thames by the previous owner for 16yrs she was'nt glazed.

I belive the only glazing was over the eyes of the previous owner after 16 years /forums/images/graemlins/grin.gif
 
You must log in or register to reply here.

Share this page

Top