Doodlebugs Latest Project... Engine at front of boat?

[cuthound]

I suspect it will be cheaper and have a better outcome if Doodlebug buys a new boat which meets his needs, rather than trying to modify what he already has.

[blackrose]

 

A 5hp or so engine could be turning an alternator which then pretty much runs an electric motor at the back of the boat at tickover speed. For fast acceleration or deceleration the boat could draw on the battery bank. At locks the battery bank would be recharged.

 

Someone may have already mentioned this, but what you're suggesting is converting kinetic energy from the engine to electrical energy driving a motor, with (if I've understood correctly) a bank of batteries to act as a sort of buffer between the two.

 

The thing I've never really understood when I've seen boats with diesel generators driving hydraulic systems to the propshaft for example, is why wouldn't you just drive the propshaft with the primary engine? Every time you convert one form of energy to another there are losses and the efficiency of the overall system is reduced.

 

The technical experts will excuse me if I've got some of my terminology wrong - I'm sure you get the general idea of what I'm saying. I suppose if the efficiency losses are manageable then it can work - we do see hydraulically and electrically driven boats - but I still don't really understand why you'd deliberately design additional inefficiencies into the propulsion system if they aren't necessary?

Edited March 7, 2016 by blackrose

[Alan de Enfield]

I suspect it will be cheaper and have a better outcome if Doodlebug buys a new boat which meets his needs, rather than trying to modify what he already has.

 

There is some element of truth in that - particularly as it is / was as 23 foot boat (I think) that has been stretched a few feet, and, being designed for an outboard. has nowhere for an inboard engine, either 'front or back'.

 

However, the 'fun' appears to be in the trying - ala 'jerrycan' cassette toilet and pump system.

[Hawkmoth]

Doodlebug, I'm sure you have considered the cable cross section needed to efficiently transmit around 300 amps.

Have you?

Bob

[zenataomm]

 

Someone may have already mentioned this, but what you're suggesting is converting kinetic energy from the engine to electrical energy driving a motor, with (if I've understood correctly) a bank of batteries to act as a sort of buffer between the two.

 

The thing I've never really understood when I've seen boats with diesel generators driving hydraulic systems to the propshaft for example, is why wouldn't you just drive the propshaft with the primary engine? Every time you convert one form of energy to another there are losses and the efficiency of the overall system is reduced.

 

The technical experts will excuse me if I've got some of my terminology wrong - I'm sure you get the general idea of what I'm saying. I suppose if the efficiency losses are manageable then it can work, but I still don't really understand why you'd deliberately design inefficiencies into the system?

 

I agree, using an internal combustion engine to run a generator to create hot sparks that then turn an electric motor attached to the prop or hooking the primary engine to a hydraulic pump/torque converter which in turn spins the blades is going to lose some efficiency.

 

However it alleviates the needs: -

To turn a gurt great gearbox and heavy prop shaft. (which also losses efficiency)

To ensure everything from engine mounts to prop shaft are perfectly in line.

To have the engine in line, you can have it sideways or at any angle hidden in a cupboard in the bow.

To have deep bilges under the floor to accommodate the prop shaft, you only need enough room for hydraulic hoses or cables.

 

As for "Every time you convert one form of energy to another there are losses and the efficiency of the overall system is reduced." with so many boats running around with multi cylinder 40 odd horse power engines nowadays, that's hardly an issue.

Remember when engines first came onto the cut a loaded Josher carrying 20 odd ton was shoved by a 9hp Bolinder and might have had a Butty behind it carrying even more.

[gazza]

 

Someone may have already mentioned this, but what you're suggesting is converting kinetic energy from the engine to electrical energy driving a motor, with (if I've understood correctly) a bank of batteries to act as a sort of buffer between the two.

 

The thing I've never really understood when I've seen boats with diesel generators driving hydraulic systems to the propshaft for example, is why wouldn't you just drive the propshaft with the primary engine? Every time you convert one form of energy to another there are losses and the efficiency of the overall system is reduced.

 

The technical experts will excuse me if I've got some of my terminology wrong - I'm sure you get the general idea of what I'm saying. I suppose if the efficiency losses are manageable then it can work - we do see hydraulically and electrically driven boats - but I still don't really understand why you'd deliberately design additional inefficiencies into the propulsion system if they aren't necessary?

Dad had a dc30 like this one, the engine is in that locker on the port side, look at how level and clear the rear of the cabin is.

 

Hydraulic drive means the motor is out the way but comes at the cost of some efficiency losses as you point out.

 

Edited March 7, 2016 by gazza

[John V]

If efficiency and economy is the requirement then the Pedalo system is tops

[peterboat]

If I wasnt always on rivers I would have an electric boat with a quality generator and a large pv array and large battery bank. It could easily work out a lot cheaper to run than a diesel engined boat

[blackrose]

 

As for "Every time you convert one form of energy to another there are losses and the efficiency of the overall system is reduced." with so many boats running around with multi cylinder 40 odd horse power engines nowadays, that's hardly an issue.

Remember when engines first came onto the cut a loaded Josher carrying 20 odd ton was shoved by a 9hp Bolinder and might have had a Butty behind it carrying even more.

 

Whether propulsion efficiency is an issue depends to some extent on what sort of waterways the boat is on. If you know you're just sticking to the safety of still waters on canals then it's certainly less of an issue - but remember all those losses cost money in terms of fuel efficiency. If on the other hand, the boat's going to be on rivers and tideways then from my own experience propulsion efficiency is very much an issue. I've increased the propulsion efficiency of my 55hp engine by re-pitching the prop it was certainly an issue for me.

Edited March 7, 2016 by blackrose

[gazza]

 

Whether propulsion efficiency is an issue depends to some extent on what sort of waterways the boat is on. If you know you're just sticking to the safety of still waters on canals then it's certainly less of an issue - but remember all those losses cost money in terms of fuel efficiency. If on the other hand, the boat's going to be on rivers and tideways then from my own experience propulsion efficiency is very much an issue. I've increased the propulsion efficiency of my 55hp engine by re-pitching the prop it was certainly an issue for me.

The broads are tidal, it nay cost a bit more in juice but with a well matched prop and motor copes just fine.

[ditchcrawler]

The broads are tidal, it nay cost a bit more in juice but with a well matched prop and motor copes just fine.

I often wonder how many canal boaters have watched the tidal flow by Yarmouth Yacht Station on the Broads? Its nothing like the Thames on yellow boards.

[ditchcrawler]

 

 

 

Reference hydraulic drives, the pump and motor have to be specifically sized for the engine hp, and sized in relation to each other for the correct reduction ratio. You can't just use any old units from the scrappy.

Quite true but he is talking of low HP , it doesn't matter if the one he uses is too big. Gear ratio is just cc capacity ratio, for a 2/1 drive the pump needs to be twice the capacity of the motor. I think I have the HP to pump size for Voac units somewhere

[Paul C]

 

Not quite. I was going with (simplified) the idea of using a 200amp motor on the back which most of the time runs using 100amps. A 100amp alternator would be running whilst on the move. That would supply the motor directly unless the motor is off (in locks) when it would charge batteries.

 

Please can you elaborate on your set up. The issue with the hydraulic system is needing a much bigger engine.

 

This troubles me. You don't need a degree in engineering to appreciate that the "transmission" of the power, or the conversion of the energy, doesn't or shuldn't massively alter the power requirement. Put simply:

 

Power at the prop = Power from engine x efficiency

 

What's the efficiency of alternator-cables-electric motor?

What's the efficiency of hydraulic pump-pipes-hydraulic motor?

 

 

 

Because I would rather avoid changing any steelwork. A project is no fun if you have to pay someone else to do it for you. Plus it would be inside and not on show. Which I like the idea of.

 

This bit also troubles me. You're installing an engine, admittedly where an engine doesn't normally go, but it must be supported properly, and I'm 99% sure that will mean at least a little steelwork involved. Every engine installation I've seen on a boat has some kind of engine bearer supports which are properly done in reasonably thick metal. You could use decent hardwood, but these will still need properly securing to the boat. And there's the ancillaries, fuel tank, etc etc to consider too.

[gazza]

 

 

An hydraulic set up at work that has performed faultlessly for 12 years stiring 2 ton of resin at a time.

 

Why you canal boaters are afraid if hydraulic systems I'll never know!

I often wonder how many canal boaters have watched the tidal flow by Yarmouth Yacht Station on the Broads? Its nothing like the Thames on yellow boards.

Indeed, and they manage on hydraulic systems.... Edited March 7, 2016 by gazza

[blackrose]

The broads are tidal, it nay cost a bit more in juice but with a well matched prop and motor copes just fine.

 

Indeed, I'm not saying it can't work, just that it can work better without the "built-in" inefficiencies.

Why you canal boaters are afraid if hydraulic systems I'll never know!

 

 

I'm not sure anyone's "afraid" are they? If a hydraulic set-up is properly installed there's no reason it can't work properly. I just think one has to understand the reason for wanting a hydraulic system in the first place.

 

Oh, and I don't see myself as a canal boater.

Edited March 7, 2016 by blackrose

[gazza]

 

Indeed, I'm not saying it can't work, just that it can work better without the "built-in" inefficiencies.

 

 

I'm not sure anyone's "afraid" are they? If a hydraulic set-up is properly installed there's no reason it can't work properly. I just think one has to understand the reason for wanting a hydraulic system in the first place.

 

Oh, and I don't see myself as a canal boater.

I wasn't really referring to you Mike, there is a general distrust on here for hydraulic systems - unfounded distrust.

 

Have a look at that DC 30 pic again, it's the prime reason for choosing hydraulic drive.

 

Pointless if the engine is in the 'normal' place, but it's hard to beat for maximising space.

 

Indeed, I'm not saying it can't work, just that it can work better without the "built-in" inefficiencies.

 

 

I'm not sure anyone's "afraid" are they? If a hydraulic set-up is properly installed there's no reason it can't work properly. I just think one has to understand the reason for wanting a hydraulic system in the first place.

 

Oh, and I don't see myself as a canal boater.

I wasn't really referring to you Mike, there is a general distrust on here for hydraulic systems - unfounded distrust.

 

Have a look at that DC 30 pic again, it's the prime reason for choosing hydraulic drive.

 

Pointless if the engine is in the 'normal' place, but it's hard to beat for maximising space.

[b0atman]

Engine to drive a hydraulic pump

Hydraulic hoses to prop (at the back of the boat)

Jobs a 'good-un'.

Maybe prop in the rudder

[David Mack]

Where are you going to put the propeller with this scheme? Does your boat have a counter stern of appropriate size and shape to accommodate the size of prop which is appropriate for a slow running lump of an engine?

[FadeToScarlet]

This video (which featured in a C&RT newsletter published on Friday) describes a boat (based in Cambridge) which runs its electric motor from batteries, charged entirely from the solar panels.

 

No sun, no boating: but they get a decent daily range

I can't see the video. There's one all-solar boat in Cambridge - he can just about make it to Waterbeach in the summer.

[Scholar Gypsy]

I can't see the video. There's one all-solar boat in Cambridge - he can just about make it to Waterbeach in the summer.

 

Does this work?

 

[waterworks]

 

 

Remember when engines first came onto the cut a loaded Josher carrying 20 odd ton was shoved by a 9hp Bolinder and might have had a Butty behind it carrying even more.

But they spun 32 inch props, at very slow rpm.

 

HP v Torque. Something I don't know much about, I just know slow turning big props are best for canal boats.

[Paul C]

I wasn't really referring to you Mike, there is a general distrust on here for hydraulic systems - unfounded distrust.

 

Have a look at that DC 30 pic again, it's the prime reason for choosing hydraulic drive.

 

Pointless if the engine is in the 'normal' place, but it's hard to beat for maximising space.

 

 

 

The entire fleet of Claymoore's boats used to be hydraulic drive. EVERY time there was a breakdown, it invariably meant send a large taxi or two to where the boat is and refund the hirer. They switched over to a fleet with conventional transmissions over time, and now have no such issues - if a gearbox problem occurs, they can fix it by the canalside if its an issue not involving the internals of the gearbox; and if its the gearbox itself, they can normally swap it in about 4 hours or so and not need to cancel/refund the hire.

[gazza]

 

The entire fleet of Claymoore's boats used to be hydraulic drive. EVERY time there was a breakdown, it invariably meant send a large taxi or two to where the boat is and refund the hirer. They switched over to a fleet with conventional transmissions over time, and now have no such issues - if a gearbox problem occurs, they can fix it by the canalside if its an issue not involving the internals of the gearbox; and if its the gearbox itself, they can normally swap it in about 4 hours or so and not need to cancel/refund the hire.

Who ever specd it wants a kick up the arse.

 

Huge amounts of broads hire boats were hydraulic drive for good reason.

Edited March 7, 2016 by gazza

[bargemast]

Of course I'm not you Doodlebug, but if I were, I wouldn't do it, it may be something nice to dream about that could help you you have some wonderful engine dreams.

 

The good thing with dreams is that everything is possible, and as a bonus, it's all free.

 

But.......once to start trying to realise a project like this, and you'll find out soon enough that it's not going to do what you expected, you won't be happy and you've wasted a lot of time and surely money too.

 

 

There's nothing wrong with these Lister engines, but they weren't made to do what you want one to do for you.

 

I had a bigger version of one of these a twin cylinder CS2/12 as a donkey engine of a barge I once owned, the engine was bought second hand by the previous owner of the barge, and had been used quite intensively for 25 years when I bought the barge, I kept her for 5 years, she was never overhauled and was still running perfectly well.

 

The work this engine did for me was, running a compressor, a big ballast-pump, a deckwash pump and a big 24Volt dynamo, for most purposes there were belts on pullys, but for the dynamo I had a belt over one of the big flywheels, and the engine was only idling to charge the batteries, doing I guess between 100 and 150 revs/min, if I'd knew then what I know now, I would have kept that engine, which would have lasted forever or maybe even longer.

 

Do continue dreaming, that's without any danger, but please don't do it for real.

 

Peter.

[the barnacle]

i restore stationary engines - the early hit n miss are stillsome of the most economical to run - great for use as a charging unit / power unit.