Props vs Jet drives.....

[Jayen4]

I was just wondering,if you could build a boat to your exact spec, which is the best drive system,props or jet drives ?? What are the pros and cons for each method ?? Could you ,for instance,design and use a jet drive on a narrowboat or houseboat ??

[ChrisPy]

I was just wondering,if you could build a boat to your exact spec, which is the best drive system,props or jet drives ?? What are the pros and cons for each method ?? Could you ,for instance,design and use a jet drive on a narrowboat or houseboat ??

I s'pose a thruster is a low speed jet drive. they work well enough sideways so they should be OK going forward.

[RLWP]

I was just wondering,if you could build a boat to your exact spec, which is the best drive system,props or jet drives ?? What are the pros and cons for each method ?? Could you ,for instance,design and use a jet drive on a narrowboat or houseboat ??

 

You could design a narrowboat with jets, and I'm sure I have seen pictures of one. So that's one in all of the narrowboats that exist.

 

Either you use a prop or you build an experimental boat and become your own development engineer

 

Welcome to the forum by the way, and please keep asking questions, it will help you form your ideas, and we do like to help

 

Richard

[Jayen4]

You could design a narrowboat with jets, and I'm sure I have seen pictures of one. So that's one in all of the narrowboats that exist.

 

Either you use a prop or you build an experimental boat and become your own development engineer

 

Welcome to the forum by the way, and please keep asking questions, it will help you form your ideas, and we do like to help

 

Richard

 

 

 

Thank you Richard.... .

 

Oh I have lots of questions (and ideas)... I do like to explore the accepted 'norms' and come up with my own way of doing things.... Comes from being an apprentice trained truck mechanic ! . Don't know much about boats...yet,but I'll get there.

[PhilR]

I was just wondering,if you could build a boat to your exact spec, which is the best drive system,props or jet drives ?? What are the pros and cons for each method ?? Could you ,for instance,design and use a jet drive on a narrowboat or houseboat ??

 

Jet drives are nothing new on the inland waterways. People were talking about them and selling them 40 or 50 years ago. Some people even fitted them to inland boats.

 

HOWEVER, I have never heard of anyone who has owned/used a jet drive for more than a year or so. That might ring a few alarm bells for you? .................................

[PhilR]

Thank you Richard.... .

 

Oh I have lots of questions (and ideas)... I do like to explore the accepted 'norms' and come up with my own way of doing things.... Comes from being an apprentice trained truck mechanic ! . Don't know much about boats...yet,but I'll get there.

 

Hi Jayen4

 

I admire your way of exploring things etc. But, (and I don't intend this post to be patronising etc) over many years loads of experiments have been made for better forms of propulsion on the inland waterways. Most (all?) of them have failed due to a lack of robustness in the design of the drive system. I really think you should spend a few months boating with traditional propulsion systems before considering designing anything new. Any drive/propulsion system which isn't up to handling sprung matresses, supermarket trolleys etc on the prop won't last long.

 

Good luck though.

 

Phil

[Jayen4]

Hi Jayen4

 

I admire your way of exploring things etc. But, (and I don't intend this post to be patronising etc) over many years loads of experiments have been made for better forms of propulsion on the inland waterways. Most (all?) of them have failed due to a lack of robustness in the design of the drive system. I really think you should spend a few months boating with traditional propulsion systems before considering designing anything new. Any drive/propulsion system which isn't up to handling sprung matresses, supermarket trolleys etc on the prop won't last long.

 

Good luck though.

 

Phil

 

 

 

Hi Phil.

Oh I'm famous for over engineering things but I hear what you say..... Actually,your comment about the rubbish that you may encounter under the water is why I was thinking about jet drives. I suppose one of the accessories you'd need on the boat would be a full diving suit,eh ?? lol

[bargemast]

I was just wondering,if you could build a boat to your exact spec, which is the best drive system,props or jet drives ?? What are the pros and cons for each method ?? Could you ,for instance,design and use a jet drive on a narrowboat or houseboat ??

 

 

If I were you, I wouldn't bother with a jet-drive. I worked for a while on a canal-tripboat with a Castoldi jet-drive, and I can assure you that it was nothing but missery.

This was on a little used canal in France, named "Canal de l'Ourc", which is not very deep and full of plants under water. Those plants, and plastic bags etc are sucked-up against the turbine inlet grill, with as result is stopping the drive, which means that you can't stop by reversing and lose steering, sometimes I managed to free the inlet grill if there was enough forward motion before this happened, by stopping the engine with luck the blockage would wash of the grill because of the water flow.

 

An old friend of mine worked on waterbusses in London and they found a solution for the problem by fitting a reverse gearbox to enable you to back flush, and get rid of everything that was bocking the inlet grill. If the water is deep enough and fairly clean it makes for an extremely well maneouvring boat.

 

A while ago someone showed some photographs on the forum of a "Kitchen rudder" on his narrowboat which would probably be a much cheaper solution.

 

Peter.

[twbm]

If you want to be innovative and build something that would really help on the canals as they are today, something that either keeps crap off the prop without impeding water flow or steering, or instantly macerates it, would be a good earner I think

[Rick-n-Jo]

If you want to be innovative and build something that would really help on the canals as they are today, something that either keeps crap off the prop without impeding water flow or steering, or instantly macerates it, would be a good earner I think

 

There is a propulsion system available that completely eliminates prop fouling and trips down the weed hatch........................................

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I'll get my (waist)coat...

 

 

R

[Jayen4]

If you want to be innovative and build something that would really help on the canals as they are today, something that either keeps crap off the prop without impeding water flow or steering, or instantly macerates it, would be a good earner I think

 

 

 

Hmmm....... I've got an idea for something that would probably help in that department. (Analytical mind in overdrive here ! lol) . Has anybody got a pic or 2 that you could post on here of the underside of the boats prop or drive area ?? I think I have a solution for that problem tho'..... (I'm assuming that the vast majority of boats hulls are steel.)

 

The points that Bargemast brought up are very interesting tho'..... What's a 'kitchen rudder'??

Edited August 1, 2010 by Jayen4

[ChrisPy]

There is a propulsion system available that completely eliminates prop fouling and trips down the weed hatch........................................

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I'll get my (waist)coat...

 

 

R

just creates an environmental problem by fouling the towpath though. prob'ly creates a disproportional volume of greenhouse gases as well, just like the patronising cows.

[Derek R.]

Kitchen rudder CLICKY.

 

Your enthusiasm is to be admired, but take heed of the experience of the past - those who ignore the past, are doomed to repeat the failures.

Whilst that sounds like 'We don't want nothing new', and by default that would prevent any progress, the fact is - what is currently used and widespread, is so because it works!

 

Twin props, tunnels around the prop gear, twin rudders - have all been 'tried', but in general the complexity that was inherent in such systems have led to them being abandoned. The biggest problem on the cut is rubbish, lack of depth, and damage caused from underwater obstructions. And wide open prop area is bound to get fouled with something. But no matter what kind of guard, grill, or filtering device can be produced, the variety of underwater 'content' will most definitely find its way to infiltrating, fouling, and causing problems. Plastic shopping bags, windblown plastic coal bags, items of clothing, curtains, carpets, wire, fishing line, rope and much more besides are the enemy. With an open prop, you have the best chance of clearing this stuff from the bank with a good hook. Even an anti-cavitation plate can cause a real problem when getting something off the blade. Encapsulate and surround it with grills and such would make prop fouling a disaster.

 

Get yourself off to some boatyards and take a look at underwater shapes and arrangements, and bear in mind the essential components of propulsion and steering - prop and rudder - will need to be protected from contact with muck and masonry along the canal edge - twin props fail for this reason, too close to possible damage.

 

All the best - Derek

 

EDIT: Paddle wheels have been tried too, and the little reed cutters as were used by British Waterways had them as they were less likley to get fouled inshallow waters. But in the main, they take up space and are high maintenace items - complex bracketry and blades.

Edited August 1, 2010 by Derek R.

[bargemast]

The points that Bargemast brought up are very interesting tho'..... What's a 'kitchen rudder'??

 

 

If you want to see some interesting photographs of a "kitchen rudder" you should go to the build blogs and check-out:

 

N.B. Trilby, New Shell, DIY fit out

 

That will be good reading for you, and also will give you an idea about a different propulsion system, while you're at it check-out the other building blogs aswell, as they will supply you with lots of useful information if you want to know more about canal boats.

 

Peter.

[Jayen4]

Thank you Derek & Peter.....lots of info there and very useful ! I shall go off and have a read of the suggested 'build blog' and others too. I'm here to learn and maybe make some useful suggestions (Brain like a sponge ! lol) .

If I start rattling on too much,just tell me to 'shut it' !

[NiceNarrowboat]

I own a jetski and a narrowboat. I believe jetskis have jets because they are safer and won't be cut to bits if you fall off. However, as fuel economy goes...forget it.

 

Interestingly, we were talking about this topic a couple of days ago.

 

Shameless bit of self-promotion follows:

 

GBJetski2010

[twbm]

I own a jetski and a narrowboat. I believe jetskis have jets because they are safer and won't be cut to bits if you fall off. However, as fuel economy goes...forget it.

 

Interestingly, we were talking about this topic a couple of days ago.

 

Shameless bit of self-promotion follows:

 

GBJetski2010

 

Round Britian on a Jet Ski: Keep us posted re progress - should make interesting reading. If you need a hotel in Southampton let me know.

[Peter R]

By the sound of it 'kitchen rudder' would be the technical term for this arrangement then.

 

 

I'm sure there is a device already on the market that can be fitted to the propshaft that is supposed to stop things getting wrapped around it by shredding them. I think it was developed for the yacht market, and I can't recall ever hearing of one fitted to a NB. I suspect that whilst it would probably cope with rope and seaweed, mattresses, shopping trolleys etc would be beyond it!

 

Peter

[bargemast]

By the sound of it 'kitchen rudder' would be the technical term for this arrangement then.

 

 

I'm sure there is a device already on the market that can be fitted to the propshaft that is supposed to stop things getting wrapped around it by shredding them. I think it was developed for the yacht market, and I can't recall ever hearing of one fitted to a NB. I suspect that whilst it would probably cope with rope and seaweed, mattresses, shopping trolleys etc would be beyond it!

 

Peter

 

 

No, I don't think so, by the looks of it this is just a tube over the prop that will act as rudder, by directing the flow with the tube. Will make it easier to reverse in the desired direction, but very hard to clear the prop.

 

Peter.

[mykaskin]

By the sound of it 'kitchen rudder' would be the technical term for this arrangement then.

 

 

Thats a ducted propeller:

 

http://www.navweaps.com/index_tech/tech-023.htm

Basically increases thrust (as the water can't get around the edges of the tips). I suspect it would be a nightmare to remove anything around the blade, and something could get trapped in the tunnel.

 

Can't remember if I imaged it, but did someone make one that opened up for prop clearance?

 

Mike

[Derek R.]

Close up of CHERTSEY's underwater arrangement, and common to the vast majority of ex-working boats LINK. The prop has maximum 'water' available, minimum obstruction, and good access from the bank with a hook.

 

Whilst it's not quite the same thing, take a look at the new 'baffles' put in gate paddles and see how much rubbish gets caught in them affecting the flow to a degree that reduces their efficiency to less than half.

 

Derek

[FadeToScarlet]

If you want to be innovative and build something that would really help on the canals as they are today, something that either keeps crap off the prop without impeding water flow or steering, or instantly macerates it, would be a good earner I think

 

The Middle Level commissioners' weedcutting and workboats have archimedes screws- which are much better at coping with the absurd mounts of weed that they can get. Probably cope better with shopping trolleys, etc., too, because there's no gaps for things to get wedged in.

[c c]

I was just wondering,if you could build a boat to your exact spec, which is the best drive system,props or jet drives ?? What are the pros and cons for each method ?? Could you ,for instance,design and use a jet drive on a narrowboat or houseboat ??

 

I have been playing with the idea of building a boat without a diesel engine or tiller but with a one of the modern quiet watercoled diesel generators powering every electric demand you could wish for plus a 240v electric motor to drive the prop with steering by bow/stern thruster. Has anyone tried this? There must be problems or we would have seen it already.

[bargemast]

I have been playing with the idea of building a boat without a diesel engine or tiller but with a one of the modern quiet watercoled diesel generators powering every electric demand you could wish for plus a 240v electric motor to drive the prop with steering by bow/stern thruster. Has anyone tried this? There must be problems or we would have seen it already.

 

 

We used to have a couple of Diesel-Electric Tug-boats in Amsterdam harbour, they were nice to drive, as you could make their props turn as slow as you liked, which was ideal for delicate jobs.

 

On the canals, I know of a few boats that have a silent diesel engine driving an hydraulic pump with thrusters bow/stern and for the propulsion, there aswell you can regulate the flow to the hyrau motors to have the prop turn as slow as you like.

 

Even in very strong current they can keep their position and make perfect lateral movements if needed, like when mooring somewhere along a quai where there are boats breasted up in front and behind with just enough space left for them to tie-up.

 

Peter.

[Morat]

The Royal Navy are doing it with their latest all electric ships....but whether you'll get much use out of electric aircraft lifts or railguns on a nb I'm not so sure Scary Warships

 

To be serious for a sec, surely you'd be better off with a 12V (or maybe 48V) brushless DC motor for your main drive than a 240V one? It would let you run at generator voltage and save losses when you convert to 240V AC...

Edited August 3, 2010 by Morat