Richardw's Narrow Boat Project-Below The Waterline

Discussion in 'Metal Boat Building' started by richardw66, Dec 3, 2013.

  1. richardw66
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    richardw66 Junior Member


    My name is Richard Wilkinson, I am a new member but I have been visiting this site the past few months harvesting information because I am embarking on a project of designing a new 62ft Live Aboard Narrow Boat.

    Apart from my intended construction start date which is Spring 2015 anything can change. I do have a lot of ideas myself but I am open to suggestions that either confirm or criticise the very best way of doing things based upon what I appreciate for some members is years of experience.
    Many of you may have been following my other forums on the subjects of ‘Plate Thickness’ and ‘Bilge & Ballast’ and now it’s time to gather thoughts regarding the best shape for a Narrow Boat to be below the waterline whilst still having to work within the confines of the ‘Box Cross Section’.

    To kick thing off I’ll start with the mention that I have come across rumours of a development known as an ‘Eco Bow’ that was supposedly developed by “a Scottish University” and built by Alvechurch Narrowboats but even their own website is very sketchy for detail.

    A trawl though Google searching under ‘Eco Bow’ came up with a blog dated 2 years ago from another person with a boat called Gecko who had come across one of these Eco Bow Boats and took the photos of which you can see below. The boat was obviously a new build back then prior to fit-out and windows,I don’t know where the photos were taken but it mentioned in the article that the boat was on route to Yelvertoft Marina for completion.

    It just so happens that I live just 5 miles away from Yelvertoft so last weekend I took a drive out to see of the off chance if the boat was there. It turned out that I was lucky because it was and I was even more luckier because the owner, a Mr Len White was very approachable and willing to share ideas on construction. Len has now become my new best friend and has arranged that the next time I visit if I take a pen drive with me he’ll give me almost 2000 photos of the boat under construction which was undertaken working off old photos.

    I’ll be paying my next visit this coming weekend to find out more and report back. It turns out the Eco Bow was developed back in the early 70s in by an English University and funded by the British Inland Waterways as it was back then. Apprarently it was not widely publicised because the authorities thought the boat would go too fast!

    The first photo is of the bow arrangement the water is just clear enough to make out the shape BTW and the anodes, there is a bow thruster tube fitted but no thruster as it has turned out unnecessary as the boat handles very responsively.

    The second photo is of the stern showing the design of the swim as seen from the inside of the engine bay. I’ve looked at scores of narrow boats but I have never seen one where the shape of the swim changes from convex to concave before the propeller but it obviously works because photo 3 shows the boat in action and what Len says is the typical wash given out at 4 mph cruising speed.

    This is a 70ft boat that one would normally expect to see a 45 to 50 hp engine and yet this eco boat only has a 35 hp engine and on a river is capable of making nearly twice that speed. It has a shallow 22in draft and the cabin sides and roof are built from 3mm plate to give a low centre of gravity. The boat was certainly stable as when Len and I stood on the gunwale it hardly moved where as a very nice looking traditional boat moored alongside experienced a definite list performing the same exercise because it was said to be too top heavy

    In contrast I have also added a photo that although may not be quite a typical example does go to a long way to demonstrate what sort of wash can be expected from more traditional and cheaper bow designs.
    All in all I believe the Eco Bow is well worth a closer inspection and I’d be grateful to hear others views on the subject.

    < Photo Credit: Gecko's Progress >

    Attached Files:

    Last edited by a moderator: Apr 23, 2017
  2. SukiSolo
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    SukiSolo Senior Member

    I could have guaranteed that the old traditional hulls were not too efficient.
    Anyway, here's what I dragged up about the Eco Hull boat but trying to get lines drawings etc might be fun.

    Quote from the following link

    Alvechurch Boat Centre Eco-Hulls Case Study
    Around ten years ago, the Alvechurch Boat Centre, one of the leading English Hire Boat operators,
    undertook some research in conjunction with British Waterways and the University of Glasgow to
    investigate the development of an eco-hull design for the replacement of their hire boat fleet.
    Following this research, some 14 craft were constructed and entered into service. The costs in fabricating
    the hulls, which included the provision of a bulbous underwater bow and changes to the stern to allow the
    propeller to get a more efficient “ grip” of the water, resulted in an additional average cost of £1,000 per
    Research carried out on these craft demonstrated that the eco-hull design resulted in a 15 -30% reduction
    in bow wave, a 5-10% reduction in the stern wave and up to 40% less pressure disturbance on the canal
    bed - thereby also diminishing the environmental impacts on plant, fish and animal life within the canal
    Given the above results, it was anticipated that there would be an annual saving in fuel costs which would,
    in turn, justify the extra investment over the operating life of the hull. However, the craft were in fact
    driven faster - so the breaking wash was the same as before, and fuel consumption increased
    As a consequence when the craft were due to be replaced again, tradition hulls were fabricated. Eco hulls
    are still available and are constructed by the Alvechurch Boat Builders but only as one-off orders.

    Quite amusing to think they were driven faster in a 4Kn limit! Did the old ones just put up that wash at 2Kn?

    There will be as good or better solution, but there may well be a small fabrication cost penalty.
  3. richardw66
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    richardw66 Junior Member

    Suki Solo,

    Thanks for that, it is interesting in the report that the information source is Alvecchurch boats and mentions Glasgow University thereby giving them credit but on there own website they are described as a Scottish University.

    Len White who owns the boat did tell me who did the research but it went in nod ear and out of the other but I'm sure he might have said Newcastle University but definitely back in the 70s where they fitted different shaped forms and sensors under the waterline to the front of a canal boat and tested it out on the river, possibly the Tyne. The description he made gave me the impression it was a trial and error suck it a see kind of thing rather than a scale model in a testing tank experiment. Perhaps that was the original experimentation that predates the Glasgow university and Alvechurch stuff years later and all they did was resurrect the idea. I'll find out for sure this coming weekend and report back.

    You've got to admit it is pretty strange there is very little detail information out there on the web like as if it almost never existed.

    The Eco bow feature on Len's boat is vertical and made from a cut-down piece of CHS off a motorway overhead gantry sign. In fact the whole boat is made from whatever was available including 'second grade' plates that were not quite uniform in thickness and a bargain price as 2 years ago the 10 tonnes of steel used was just £6k.
  4. richardw66
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    richardw66 Junior Member

    Oh yes the speed is measured in miles per hour (mph), not kilometres (kph). The inland waterways speed limit is 4 mph which is a brisk walking pace and equal to 6.43kph. I'm not quite sure what the river speed limit is but 7.5mph would equate to 12kph so not as slow as you thought.
  5. richardw66
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    richardw66 Junior Member

    Suki Solo,

    Damn! I know what you're going to say because it's just occurred to me; kts = knots, so you're right!

    I thought it was a mis print or typo error. It's just strange to use knots for measuring speed on internal waterways but suppose its nautical.

    If I remember back to my powerboat training; doesn't one knot equate to one second of a degree of movement of the earths angle? Or something like that.
  6. Stumble
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    Stumble Senior Member

    1kn is one nautical mile per hour. It used to be one minute of one degree latitude. But has been somewhat lengthened (by about a meter) for standardization purposes.
  7. DCockey
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    DCockey Senior Member

  8. SukiSolo
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    SukiSolo Senior Member

    I probably got so used to the speed limits on the Lower Tidal Thames which are/were in knots not mph....:)

    Above Wandsworth railway (tube) bridge 7Kn and below 10Kn. When I sailed at Putney, Ranelagh SC we had a partial exemption for our safety boats. The use of Knots was on the riverbank signeage at locks on the Thames and other points on the waterway. I averaged 9kn round the course on one occassion in my own singlehander....above the Wandsworth limit. Never got stopped by the PLA (Port of London Authority) or river Police though. One ridiculous gust on another occassion had the boat going at 17kn+....maybe even touched 20 briefly.

    The inland waterways are a bit different so mph makes more sense for them, especially as the original boats were human or horse powered. Thanks David.
  9. Simonosteopath
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    Simonosteopath Junior Member

    Hello all,
    My Name is Simon Poulter and I have been reading with great interest, and adding a little here and there to other threads started by Richard.
    My original background is in electronic and mechanical engineering. I am currently in the medical profession.
    I am also gathering information with regard to having a 67(ish)foot narrowboat built for live aboard for me, my wife and one-year-old. We plan to do a lot of continuous cruising to begin with and then maybe settle at a semi-permanent mooring later on.

    Hi Richard. The eco bow was something I also came across whilst looking at different hull designs about a year ago. 'S' shaped aft swims also make a lot of sense. Like yourself, I was sure more could be done to improve the efficiency of traditional hulls. At the same time though, I find the overall shape of the traditional canal boat above the waterline, the narrowboat, very appealing. I will therefore be trying to incorporate as much as possible of whatever technological improvements can be made, in terms of efficiency and comfort, without ending up with something that is no-longer recognisable as a narrowboat.
    I hope to make good use of PV solar panels when moored and use clever plumbing so that engine cooling can be diverted to heat the cabin through a wet underfloor central heating system, and have the boiler part of the system controllable via my mobile phone.
    I really like Richard's progression with his section drawings, especially in terms of what may be done to maximise space, for example: Using a wider side panel that may be folded to form part of the roof, thereby making the cabin sides more vertical and not having to waste metal by using a larger roof panel that would need cutting down.

    I have a little inland sailing experience, both sail and motor power, but I know I will pick up a lot of wisdom here!

  10. aspirant
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    aspirant New Member

    Eco Hull

    Hi Richard,

    perhaps you are still following this thread.
    I also tried to find information to this "Eco Bow" I heard about. An orbituary led me to Archie Ferguson. According to this orbituary, he and his colleague R.C. McGregor did the research "at a Scottish university" mentioned by Alvechurch.
    They published (at least) one paper:

    TOPICS IN ENGINEERING - Seminar, Marine engineering: design and operation of ships and offshore structures

    On the limitation of erosion of the canal and river banks by inland waterways vessels

    1994, pages 253-260; ISBN: 1853122483

    Right now, I am hunting for a copy of this paper. If you are still interessted, I could send it to you.
  11. DCockey
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    DCockey Senior Member

    Based on the ISBN the paper is in:
    NEVA: 1st: Design and Operation of Ships and Offshore Structures - Proceedings of the 1st International Conference (Topics in Engineering)
    by Murthy, T.K.S.; Brebbia, C. A.
    Publisher:WIT Press, 1993 is a good way to find a copy. Go to the website and put the ISBN in the ISBN field and click on Search.
  12. nbGecko
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    nbGecko New Member

    Any progress to report on your Eco boat?
  13. Dan Holdsworth
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    Dan Holdsworth New Member

    Looking at this thread, it seems to me that a little thinking outside the normal conventions might be in order.

    So, if you look at the current traditional design of canal boats, the boat propulsion system is completely conventional yet the boat is always operating in shallow water. Similarly the hull is always going to be in shallow water, frequently in narrow waterways. The major drag forces are going to be induced by having to push water out of the way of the craft, and in doing so a turbulent flow will be created in which the propeller will have to operate somehow; the propeller is also going to be operating in a fairly dirty and debris-prone environment.

    So, working from this, how's about we try and solve most of these problems in one go?

    Redesign the hull so that the bottom isn't quite flat, but has two "pontoons" projecting downwards with a hollow section along the mid-line of the boat. Put ballast into these two outer sections for stability. Mount a Voith Schneider propeller at the FRONT of the hull where it is running in non-turbulent flow, projecting water down under the boat along this hollow section. This has the other effect of forcing water that would create a bow wave to run under the boat to the rear. The VS prop might as well be driven by hydraulics, since sooner or later it will get fouled in something, and to clear it the easiest way is to rotate the entire unit up and out of the water; hydraulics can be used for that as well as for propulsion.

    The control point for the boat can be anywhere; you might as well have dual controls both at the front of the boat under cover for use in inclement weather, and at the back in a more normal steering position. Mount a lateral thruster at the back to improve control, and also put the engine at the back as well with wide-bore hydraulic lines leading both forward to the main prop and back to the rear thruster. If controlling the boat from the front position, rear view mirrors may be needed, but the experience will be a much quieter one for the operator.

    Now, the question is, does this sound like complete insanity or not?
  14. wet feet
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    wet feet Senior Member

    Not the best idea considering the amount of debris in a lot of canals.The complication and expense of a Voith Schneider drive are a significant obstacle and it isn't a particularly easy task to build a weed hatch over one to allow the fouling to be cleared.The cost of the propulsion system alone might well exceed the cost of building a conventional hull with an engine and sterngear.However,if you want to build one and report back I'm sure any information would be eagerly received.

  15. thjakits
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    thjakits New Member

    I would think a Voith Schneider would be quite a expensive drive!
    Maybe a Schottel drive or pod drive with a Prop protector (the Ring around the prop ina a Schottel drive will also work as a protector....)

    I find the idea to put the propulsion at the bow quite intriguing - especially considering the often observed effects of constricted water-ways....
    I will need to let this dwell for a while....

    The tunnel under the boat - you are looking for more overall draft with that - which is not a good thing....

    HOW about drop down side plates for a few feet back from the bow - maybe 10-12 feet back, 4 inches down, which will channel the water under the boat and backwards and then let it slip out the side, where it will be restricted anyways (we are talking the extreme narrow and/or shallow situations here...), the side plates should be just hanging there by their own weight in guides - this way they can bump up if the run into the ground....

    HOWEVER - how would you shape the bow to accomodate the drive (whatever propulsion system you use...) - WITHOUT going BELOW the bottom of the boat?!
    YOu would still need some shape that pushes the water underneath and to the sides - while hanging the drive in front of everything - aesthetics might suffer!!

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