Quick question about two engine use on the Thames

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GAJ52

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With two engines running on my Birchwood, to maintain an acceptable speed i.e. no wash etc. the engines (diesel) are running practically at idle. Although this is good for fuel economy I do wonder how this effects the engine health long term due to oil pressure being at a lower value for most of the time.

I have tried running with just one engine for a short period as an experiment, and my boat handles very well with only minor yawing tendency. Just curious if other users on the Thames run with one engine shut down. The only thing I could think of against this is gearbox lubrication as the propeller is still turning - any thoughts ?

Glen
 
Hi same problem with my Volvo 41a diesels,,as a retired marine engineer (ships) main problems with mine was engines remained to cold at prolonged idle,and will cause cylinder bore glazing ,leading to premature expensive engine repairs.
as I use my boat mainly on inland water ways I fitted webasto water heaters to both engines to avoid this ,keeps temps at around 70 deg c at idle cruising .and not expensive to run,
AS for gearbox lubrication I can not reliably comment but lots of mobo's run on single engines on non tidal Medway ,only running two units when needed for better manoeuvring
 
I use two engines, or one on the upper thames (TAMD40b) and temperatures run at an acceptable degree. These engines have two thermostats, one limits coolant flow to keep temperature up, the other opens up full flow for tidal trips!

Gearbox lubrication should not be an issue on popular gearboxes (You didn't say what yours were though, worth Googling...)

Fifty Shades runs almost perfectly straight once underway on either engine! Best not forget you're on only one when trying to stop in a hurry though, thats quite funny!
 
Which makes you wonder why people keep boats with twin engines, and high powered single engines, permanently on inland waterways when they have been designed for open waters?
 
Quite simple.

I can turn my boat on a sixpence, even in a high wind, swivel it in a lock without moving fore or aft, and still run it on one engine between locks at 0.7mpg

And then, twice a year hit central london or beyond at higher speeds than a single, with the knowledge that if an engine fails I can still get home.
 
AuntyRinum said:
Which makes you wonder why people keep boats with twin engines, and high powered single engines, permanently on inland waterways when they have been designed for open waters?
Click to expand...

My reason is slowly degenerating mobility problems ,my princess 30ds on shafts ,2 x 200 hp diesels was designed for open water and was used as such.,but poor legs and age make it safer to use in land ,,the boat lay out suits me fine being 6ft 2ins so wont change it,so just make it usable now,, happy cruising ;-)
 
No Regrets said:
https://www.marinepartseurope.com/en/volvo-penta-explodedview-7745630-26-19479.aspx

Oh yes it does!?
Click to expand...

hi thanks for that ,I recall now ,I changed both with asap items when I became in lander lol. original specs had changed ,both operate at about 80 degrees ,and found some old but new units in boat spares ,tried them as well.(in fact still fitted) . my problem 1 engine 700rpm ish 5 knots .2 engines 8/9 knots....local speed limit 5 knots engines at idle only generate 35/40 degrees , when tidal/estuary 1500 rpm plus gives a good 70 degrees , I know could re prop,and not right boat for my now use but webastos keep temps up on river ,thanks for input boat history and local owners from new still around ,,,,will probably retire from boating next season, 34 knots a bit fast for the Medway.or maybe look for a freeman puddle jumper for my dotage . thanks again :-)
 
incidentally was advised that 41a's lower compression than b'S and low loads at idle do not produce much heat in my boats installation, but am open to an education .cheers bob
 
A few replies on 'why have two engines on the Thames', that was not my question.

I would still like to hear from a few more twin engine Thames users if they normally use two or one engine when travelling between locks, and which is the most common configuration. As I'm reasonably new to boating, I'm still trying to learn how to operate my boat in the most efficient and safe manner by listening to the more experienced mariners on this forum.

Thanks again for your advice, Glen
 
Not Thames, but similar. I have a twin engined boat on the Gt Ouse in Cambridgeshire. In some low speed limit areas I regally run on one engine to get the revs up a bit for comfort, smoothness and battery charging.

Although the boat handles OK on one engine, I cannot start from stationary on one, so have to fire up for close quarters handling and locks, although if there is space I often come in gently and moor up on just one. The 'spare' prop freewheels as we have hydraulic gear boxes, but I don't think it does any damage, possibly due to having external thrust bearings.
I would like to think I split the running 50-50, but I know I prefer to run on the starboard engine as it is not under my seat and the sound deadening is slightly better on that side!!!
 
Horses for courses really,whatever you are comfortable with.
I run on 1or 2 depending on my mood,how windy etc at basically idle sending out smoke signals or the rowers get irate:),it's about a 50/50 split amongst people I know.Whether you run one or both on The Thames they ain't really working hard enough,a diesel likes to be worked.If possible get down to the sea reaches and open her up at least once a year to blow the cobwebs away.I try to get down that way couple of times if possible,the smoke soon clears and they are doing what they were designed for!!
What engines do you have?
 
We are on the Broads and have visited the Thames. When inland we often run on one engine to get higher revs, warmer engines and halve the engine hours. It works on our current boat becasue the steering doesn't rely on either engine for power and crucially our gearboxes (ZF) don't require an engine to be running to get lubrication. You should check this for your gearboxes as the shaft will keep turning when the engine is off.

I tend to do half an hour each side to avoid the shaft cutlass bearings running too warm (ours are lubricated by water from the engine raw water system).

We have a skeg keel so that combined with around 10 to 15 degrees of helm and putting the trim tab on the same side as the running engine down keeps us on a steady course. The thing is to remember that you have less maneuverability and if you slow down and then speed up again you will have steerage issues untill there is sufficient way on for the rudder and trim tab to have an effect. I start the other engine if I spot potential problems and would always do so when entering/exiting a lock.

We do four knots on tickover on both engines so running on one also helps keep within the speed limit :)
 
Many thanks for the feedback, it appears running on one engine is not that unusual after all.

I'm running two BMW Mercruiser engines that idle at about 750 to 800 rpm but I have to run under 1000 rpm to stay within the speed limit on the Thames, also at very low rpms its hard to sync the two engines together, so I get more vibration (no electronic synchronisation I'm afraid), individually both engines run as smooth as silk.

Glen
 
GAJ52 said:
A few replies on 'why have two engines on the Thames', that was not my question.

I would still like to hear from a few more twin engine Thames users if they normally use two or one engine when travelling between locks, and which is the most common configuration. As I'm reasonably new to boating, I'm still trying to learn how to operate my boat in the most efficient and safe manner by listening to the more experienced mariners on this forum.

Thanks again for your advice, Glen
Click to expand...

I think I answered your question quite comprehensively!?

Two engines for manoeuvring, one for cruising efficiently between locks...

Never had an issue...
 
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