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stratford4528
United Kingdom
414 Posts |
 Posted - 27 Dec 2018 : 13:32:52
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I have mentioned this topic before but no one seems interested.
I am going to design and build a jet drive for my boat to get over the problem of shallow canals.
I would like to hear some comments |
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trevork
3949 Posts |
Posted - 27 Dec 2018 : 14:17:49
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| I suspect the lack of comments may well be down to the fact that most could not fathom a jet drive on a Norman. I assume you are thinking of some sort of powerful water pump to propel the boat?? I can see how this will make it easier to cope with shallow waters but what about steerage? |
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stratford4528
United Kingdom
414 Posts |
Posted - 27 Dec 2018 : 17:30:38
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I have thought of everything. Steering, reversing, disengaging and mounting.It would be mounted on the stern in place of the Z drive. I know when I start to build it I will come across a lot of problems.
I will test the prototype first on my 25 on my lake before making one for my 32 |
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Coming up for air
United Kingdom
6 Posts |
Posted - 27 Dec 2018 : 22:09:37
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In the 1970s when I was moored up on the Worcester & Birmingham Canal at Selly Oak myself and a friend hired a 12ft dinghy from a boatyard that had a form of jet drive outboard motor. Perhaps 3 or 4hp. We intended to explore some of the 'loops' on the BCN old main line which in those days were poorly maintained and we would not risk using a wooden or marine ply boat.
The idea seemed pretty good especially when, at that time the huge number of plastic bags and other rubbish in the cut made navigation difficult. The idea of an enclosed impellor sounded sensible. In that environment the jet outboard was hopeless. The water inlet for the jet had a screen to stop bits of wood, plastic etc getting to the impellor. Instead of hitting the impellor the rubbish and small water borne life were caught in the mesh and blocked it, thus quickly reducing the power output. The system would probably have worked well in clean deep river courses (where traditional outboards worked well) but on the canal it was hopeless.
Another novel propulsion method I saw on the North Stratford Canal at that time was applied to an ex-army plywood pontoon. The boat owner appeared to have fitted an Austin A30 engine and road gearbox into the boat and connected the engine via the car transmission shaft to the rear axle suspended above the water at the stern of the boat and had made up two paddles to impel the boat. Second gear on the road box would probably have been fine! And a paddle wheel is ideal for shallow water!
w.r. Hewer |
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df
United Kingdom
5991 Posts |
Posted - 28 Dec 2018 : 15:28:08
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Would be great for shallow sand/gravel bed but for shallow mud/silt/bag/rope bed would be a nightmare as it would suck up all the crud and either block the intake or jam the impellor itself and be much harder than a liftable prop to clear.
A big fan and a hovercraft skirt would work far better.....
A lot of the windfarm vessels use jet drive as they are working in lots of shallow sand banks but the don't come across many shopping trolleys out there.
How about a pair of large flippers mounted at either side of the transom operatd by a crankshaft? 
A few years back I did see a jet drive on ebay with a large plate that went on the underside of the hull as the intake and a daft project did cross my mind but it would have needed to be an otherwise scrap hull and very cheap as highly likely to fail, probably not to bad for gt.ouse but not for the shallower canals.
The far easier way around it is to put up with some travelling and have the boat on a proper river, part of why I travel 90 miles to the broads and back most weekends in summer when I have the gt.ouse running through my home town.
NBAS--The communal colostomy bag of the boating community.
 Visit leomagill.co.uk |
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Coming up for air
United Kingdom
6 Posts |
Posted - 28 Dec 2018 : 23:47:35
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Of course the ultimate for canal cruising would be go back to basics. Set a short post on the roof of the cabin about one third back from the bow, attach a 80/90ft rope and connect to a horse on the towpath. A nice steady 3mph should be achievable. Not bad for 1 horsepower!
Advantages: No plastic bags or worse on the prop. No engine cooling problems. No noisy/smelly diesel engine.
Disadvantages: A person would have to follow the horse with a 15foot long pole with a fork on the end to lift the rope over tv ariels, sat dish, photovoltaic cells, coal, wood, assorted junk and the content of garden centres on the top of liveaboard boats. CRT no longer permit horse drawn boats. Worrabout reducing our carbon footprint?
w.r. Hewer |
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cliveshep
Thailand
1324 Posts |
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stratford4528
United Kingdom
414 Posts |
Posted - 29 Dec 2018 : 08:20:17
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| Clive those are far to elaborate for a canal boat. My idea is very simple and will bolt on in place of the leg so the engine will not be disturbed. |
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cliveshep
Thailand
1324 Posts |
Posted - 29 Dec 2018 : 13:25:29
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Ok, but I wonder in any event if given the amount of water to be taken in to be expelled at a velocity and mass great enough for the reaction to move a 32ft Norman won't you get mega problems with the water inlet blocking?
We all joke about the rubbish in canals but super-market trolleys, fertiliser bags, and even carpets and bicycles find their way into the water.
On the River Wey where I habitually moored my boats (far cheaper than the Thames only two locks away) I had a carpet round the prop on my Ocean 30 necessitating an expensive crane out, and a bicycle in the prop of an Elysian before that requiring a boatyard chappie to go underneath as no crane available and cut it away.
Up on the Middle Levels in East Anglia where I had an ex Dutch North sea fishing boat conversion the amount of weed blocking the intake filter was scary, a few minutes running and the "barking" from the exhaust indicated another sea-water pick up blockage.
Don't know what the answer is apart from a horse lol.
Finally living the dream!
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stratford4528
United Kingdom
414 Posts |
Posted - 29 Dec 2018 : 14:25:31
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| One can only try and see if it works |
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Revolvor
United Kingdom
75 Posts |
Posted - 06 Jan 2019 : 18:28:28
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Lots of people seem to be coming up with reasons why it wont work. I hope you can prove them wrong. Good Luck!
John
Roads? Where we're going we don't need roads! |
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stratford4528
United Kingdom
414 Posts |
Posted - 07 Jan 2019 : 08:18:26
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Thank you John.
I design and make things with success . I designed and built my own wind turbine, (every single part of it) which I have been using for many years. My latest project is a tarmac processing machine I put tarmac planings off the roads in one end and hot tarmac comes out the other. So I have every confidence that I can make it work. If not it will be fun trying.
Bob |
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df
United Kingdom
5991 Posts |
Posted - 07 Jan 2019 : 17:13:27
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It can definitely be made to work it's just wether it will be useful in a shallow crud filled canal or wether it will cause the same problems in a harder to clear way.
There is no easy answer to the problem apart from dredging the canals and castrating the numptys that chuck all the junk in it.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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trevork
3949 Posts |
Posted - 07 Jan 2019 : 23:37:19
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| Always for the soft approach Dave! |
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Fred
2007 Posts |
Posted - 08 Jan 2019 : 12:54:45
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| Yuk! Now I've got visions of a canal full of discarded willies. |
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cliveshep
Thailand
1324 Posts |
Posted - 09 Jan 2019 : 03:46:20
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By all accounts Tesco, Asda and Safeway have shares in the canal network going by the number of supermarket trolleys parked in them.
They won't hurt a jet drive, but Farmer Giles fertiliser bags will certainly stop it sucking up water.
Maybe an air-driven boat is the way to go?
Using a vertical turbine compressor to suck in air, blow it out under water to give thrust? Not a jet engine per se, but the compressor part of one driven by an inboard engine but on the same principle - suck -squeeze - blow.
The last description is nothing to do with Monica Lewinsky.
Added advantage to the canals - it will aerate turgid water.
Design fees to me please!
Finally living the dream!
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Edited by - cliveshep on 09 Jan 2019 03:47:53 |
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Topic |
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Jet drive
