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Post by JohnV on Jun 18, 2021 8:29:19 GMT
depends on size of narrowboat, remember speed is a function of the square root of the waterline length,
the narrowboat I did needed about 10Kw for 6 Mph less the efficiency of the gearbox so say 9Kw with a waterline length of 72'
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Post by Deleted on Jun 18, 2021 8:58:53 GMT
I see your 40hp and raise you a 50hp, total overkill but it does give one an edge
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Post by Deleted on Jun 18, 2021 9:08:54 GMT
I would agree with that.
Having done most of my boating on a 55ft NB with a Russell Newbery DM2 there were many many days when I would have dearly loved to have a nice quiet Beta 50 instead.
Definitely.
You might remember my boat actually. Green and orange called TIGER I regularly used to pass your mooring with the narrow boat with JP3 in it and afterwards the duker replica Parglena.
There was often a light blue narrow boat badly moored between lock and bridge opposite you.
Early-mid 00s.
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Post by JohnV on Jun 18, 2021 9:22:24 GMT
I see your 40hp and raise you a 50hp, total overkill but it does give one an edge 8 litre 6 cyl 136 hp ...... totally overengined but 6 knots towing a Selby barge alongside
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Post by brummieboy on Jun 18, 2021 9:22:34 GMT
I have a Perkins 4108M with the heavy flywheel, which is governed to 2,100 and provides a miniscule 28BHP as opposed to the 47BHP from an unfettered engine. The relationship between BHP and torque and propellor size is something of a black art to me. On a 57ft narrowboat, I've plenty of speed and have towed other narrowboats with moderate success.
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Post by JohnV on Jun 18, 2021 9:37:13 GMT
as I said near the start, I think most boats are over powered (and that includes mine)
Sabina was fitted with a 4 Cyl Gleniffer of I believe round about 40hp with that she sailed the Humber carrying 80 tons of petrol and then later spent several years commercial carrying on the East Anglian coast and the Thames Estuary.
The 8 Litre 136hp engine was fitted because I was made an offer too good to refuse. It spends most of the time at around half revs or less and anything more merely produces lots of froth, cavitation and no extra speed. At those revs it sounds good, is quiet and smooth.
Don't regret for a minute buying it ....... but there is no getting away from the fact that it is much bigger than needed
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Post by Deleted on Jun 18, 2021 11:10:58 GMT
The Gleniffer will probably have been a DB4 which off the top of my head was around 36bhp @ 1000rpm.
The Daewoo is 136BHP @ 2300rpm ish.
136/2.3 = 60 so in theory the Daewoo is only 1.5 times as effective as the Gleniffer.
It would be quite interesting to see the torque curves for the two motors.
Gleniffers are stunning engines.
Proper marine units the right shape etc.
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Post by thebfg on Jun 18, 2021 13:20:01 GMT
So the one pot on witchy and foxey is bang on anything else is a waste.🙂
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Post by Deleted on Jun 18, 2021 13:32:19 GMT
"the little red thing where the engine should be", to quote Mr Stabby, is actually a very nice little proper marine engine. Bukh
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Post by Mr Stabby on Jun 18, 2021 17:28:26 GMT
I think my BMC 1.5 engine puts out about 35hp. It seems completely adequate for pushing the potato boat along and I find it easy to work on, I've owned several cars with the B series engine, albeit the petrol version so I'm used to servicing them. They used to fit the 1.5 diesel to Austin Cambridge taxis and J4 vans, but even with the 60hp petrol engines they were woefully underpowered. Seems fine for the boat though and these engines go on for ever if they are serviced regularly, I try to service it every 150 hours which I calculate to be approximately equivalent to 4,500 miles in a car.
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Post by Deleted on Jun 18, 2021 21:02:33 GMT
I think my BMC 1.5 engine puts out about 35hp. It seems completely adequate for pushing the potato boat along and I find it easy to work on, I've owned several cars with the B series engine, albeit the petrol version so I'm used to servicing them. They used to fit the 1.5 diesel to Austin Cambridge taxis and J4 vans, but even with the 60hp petrol engines they were woefully underpowered. Seems fine for the boat though and these engines go on for ever if they are serviced regularly, I try to service it every 150 hours which I calculate to be approximately equivalent to 4,500 miles in a car. Dulcinea has two identical BMC 1.5D engines. I quite like them. I also like the fact there are two Austin J4 service manuals on the boat. One for each engine. @nemesis knows that one of the engines has problems and will let me down en route to the Azores but I still sleep ok at night at least for now.
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Post by Deleted on Jun 18, 2021 21:40:43 GMT
I think my BMC 1.5 engine puts out about 35hp. It seems completely adequate for pushing the potato boat along and I find it easy to work on, I've owned several cars with the B series engine, albeit the petrol version so I'm used to servicing them. They used to fit the 1.5 diesel to Austin Cambridge taxis and J4 vans, but even with the 60hp petrol engines they were woefully underpowered. Seems fine for the boat though and these engines go on for ever if they are serviced regularly, I try to service it every 150 hours which I calculate to be approximately equivalent to 4,500 miles in a car. Dulcinea has two identical BMC 1.5D engines. I quite like them. I also like the fact there are two Austin J4 service manuals on the boat. One for each engine. @nemesis knows that one of the engines has problems and will let me down en route to the Azores but I still sleep ok at night at least for now. Don't worry about it, Evangeline will send the MI6 sub to tow you back to port.
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Post by Mr Stabby on Jun 18, 2021 21:52:15 GMT
I think my BMC 1.5 engine puts out about 35hp. It seems completely adequate for pushing the potato boat along and I find it easy to work on, I've owned several cars with the B series engine, albeit the petrol version so I'm used to servicing them. They used to fit the 1.5 diesel to Austin Cambridge taxis and J4 vans, but even with the 60hp petrol engines they were woefully underpowered. Seems fine for the boat though and these engines go on for ever if they are serviced regularly, I try to service it every 150 hours which I calculate to be approximately equivalent to 4,500 miles in a car. Dulcinea has two identical BMC 1.5D engines. I quite like them. I also like the fact there are two Austin J4 service manuals on the boat. One for each engine. @nemesis knows that one of the engines has problems and will let me down en route to the Azores but I still sleep ok at night at least for now. They are a very robust engine, and very long-lived if they have a good maintenance schedule. The only real drawback with them is that they are converted petrol engines rather than having been designed as diesel engines so they don't have piston liners and so have to be re-bored and fitted with over-sized pistons if they need re-building. Having said that, mine has around 8,000 hours on the clock and doesn't display any sign of excess wear at all, doesn't require oil top-ups between services, starts almost instantly without activating the glow plugs, a few seconds of white smoke from the exhaust after starting in mid-Winter is about it. They have no areas known for catastrophic failure, obviously they do eventually wear out and start to emit blue/black smoke but even then they keep on running until the owner gets fed up with it and has a re-build or replacement. I'm expecting mine to last at least another 8,000 miles (touch wood) but when it is eventually worn out I will probably get it re-built rather than going down the Japanese engine route.
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Post by Deleted on Jun 18, 2021 22:02:03 GMT
Dulcinea has two identical BMC 1.5D engines. I quite like them. I also like the fact there are two Austin J4 service manuals on the boat. One for each engine. @nemesis knows that one of the engines has problems and will let me down en route to the Azores but I still sleep ok at night at least for now. Don't worry about it, Evangeline will send the MI6 sub to tow you back to port. Exactly. I will get looked after whatever happens. I firmly believe this now more than ever. As it happens I had a falling out with Evangeline yesterday and it looks like she has blacklisted me. It might have been a PMQ or PMT problem but either way I think it's bad news. Maybe I need a battery with a higher CCA rating.
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Post by TonyDunkley on Jun 18, 2021 22:17:26 GMT
I have a Perkins 4108M with the heavy flywheel, which is governed to 2,100 and provides a miniscule 28BHP as opposed to the 47BHP from an unfettered engine. The relationship between BHP and torque and propellor size is something of a black art to me. On a 57ft narrowboat, I've plenty of speed and have towed other narrowboats with moderate success. Matching engine and reduction gear ratios to propeller diameter and pitch on canalboats is a black art for everyone. All the normal rules and formulae applicable to propellers working in (deep) 'open' water go out of the window. Best canalboat propeller efficiency figures are achieved with maximum propeller rpm at 500 - 600 and with the coarsest pitch the engine and reduction ratio can cope with to just reach the rated (governed) engine rpm. The 'ideal' propeller configuration for maximum propulsive thrust and boat speed from any given horsepower figure in shallow restricted width channels is 'square' - ie. diameter and pitch both the same.
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