Do you have an Eco-hull?

[RLWP]

All boats performance improves in deep water

 

Richard

[Old Son]

I have what could be termed an Eco Hull with a bulbous shape on the front. My boat was built as a one off by a builder who I was informed built boats on the Thames. I must say the boat performed very well on a fairly rough passage from Limehouse to Teddington recently.

[bargemast]

A very well known boatbuilder named MEL DAVIS built a Narrowboat with a completely different Eco-Hull about 6 years ago the boat was made to the design of the man who wanted his boat to be like that.

 

The boat is named "HARVEST" and it has electric-propulsion, there are some photo's of this hull in Mel Davis gallery

 

http://www.meldavis.com/gallery/index.php?i=086i

 

Peter.

[Coelum Ruat]

I have what could be termed an Eco Hull with a bulbous shape on the front. My boat was built as a one off by a builder who I was informed built boats on the Thames. I must say the boat performed very well on a fairly rough passage from Limehouse to Teddington recently.

 

Interesting! Do you have any scale drawings or plans?

 

A very well known boatbuilder named MEL DAVIS built a Narrowboat with a completely different Eco-Hull about 6 years ago the boat was made to the design of the man who wanted his boat to be like that.

 

The boat is named "HARVEST" and it has electric-propulsion, there are some photo's of this hull in Mel Davis gallery

 

http://www.meldavis.com/gallery/index.php?i=086i

 

Peter.

I will see if I can contact him.

 

Thanks to all who have contributed.

 

Paul

Edited September 23, 2014 by Coelum Ruat

[John C]

Many years ago, (late 80's early 90's?) a guy I worked was researching into hull design for narrow channels, that is narrowboats on canals. I assisted in some measurement of the bow wave. Alvechurch lent us two boats, one with and one without the modified bow. The method of measurement was rather crude but OK for a first look, the "eco" hull gave worse results than the "non-eco" bow. We saw the evidence of improved fuel consumption, why that should be, as far as I can remember, was never discovered.

 

I think the bulbous style of bow is called "Ostec".

 

John

[Old Son]

This is how I bought the boat

 

I don't have measurements, nothing stopping you taking some though!

Many years ago, (late 80's early 90's?) a guy I worked was researching into hull design for narrow channels, that is narrowboats on canals. I assisted in some measurement of the bow wave. Alvechurch lent us two boats, one with and one without the modified bow. The method of measurement was rather crude but OK for a first look, the "eco" hull gave worse results than the "non-eco" bow. We saw the evidence of improved fuel consumption, why that should be, as far as I can remember, was never discovered.

 

I think the bulbous style of bow is called "Ostec".

 

Johnhan

Mine is the same, I seem to make more bow wave than similar length boats travelling at the same speed.

[Coelum Ruat]

This is how I bought the boat

 

I don't have measurements, nothing stopping you taking some though!

 

Mine is the same, I seem to make more bow wave than similar length boats travelling at the same speed.

 

I would value a photo of your stern, if that's ok?

 

Paul

Many years ago, (late 80's early 90's?) a guy I worked was researching into hull design for narrow channels, that is narrowboats on canals. I assisted in some measurement of the bow wave. Alvechurch lent us two boats, one with and one without the modified bow. The method of measurement was rather crude but OK for a first look, the "eco" hull gave worse results than the "non-eco" bow. We saw the evidence of improved fuel consumption, why that should be, as far as I can remember, was never discovered.

 

I think the bulbous style of bow is called "Ostec".

 

John

 

I am very keen to discover any further details of this work. I believe Ostec Ltd was involved in measuring waves, including the pressure wave below the hull as it passed. Have you any names or contacts? PM if necessary.

 

Many thanks

 

Paul

[IanD]

One issue is that few canal boats actually have a speed log, the driver just has to have a feel for the bow wave they are accepting/expecting. If that bow wave happens at a faster speed then they go faster. The aim with the marine bulbous bow is that the underwater bit makes a bow wave 180degrees out of phase with the waterline bow so they fill in, then the boat can ride flat water rather than try to climb it's own bow wave all the time, when these ships do inches to the gallon then a few percent fuel saving as worth big money!

None of the canal "eco-hulls" can work this way, because to work this needs a bulbous submerged "nose" projecting well ahead of the normal bow. It also only gives the maximum benefit at one speed where the dip and peak cancel out, which is fine for container ships and oil tankers and liners which have a fixed cruising speed but not really for narrowboats. And it only works properly in deep water.

 

All the canal versions just seem to be variations on a blunt bow, which works in deep unrestricted water (especially submarines!) but not so well in shallow water because the water has to move out of the way faster in a restricted space.

 

It looks to me that the best solution for relatively shallow canals is one that's been known for a long time, which is long tapered swims at both ends -- this not only reduces the rate that the water has to be pushed aside but also the total amount that has to be shifted by reducing the overall displacement. The steam-powered "Firefly" that we hired in the 80s had huge bow and stern swims -- something like 15' each end on a 57' Hancock & Lane hull IIRC -- and made almost no wash, undoubtedly helped by the tiny (3 shp?) power output, but would still do about 4mph on a deep canal.

[Slim]

I chartered a 38 foot motor/sailer (Elstrom 38?) about 30 years ago that had a bulbous 'nose' protruding from the bow. No one could say why. Sailed it in some extremely heavy weather and it performed beautifully. Often wondered whether it's t*d***r as we named it contributed in any way.

 

 

 

Frank

[MarkHez]

A very well known boatbuilder named MEL DAVIS built a Narrowboat with a completely different Eco-Hull about 6 years ago the boat was made to the design of the man who wanted his boat to be like that.

 

The boat is named "HARVEST" and it has electric-propulsion, there are some photo's of this hull in Mel Davis gallery

 

http://www.meldavis.com/gallery/index.php?i=086i

 

Peter.

Harvest is moored up near my "local" at the moment, it is a wonderful if a bit strange looking boat, took my a while to work out which end was the front and which end the back to start with!

 

He was moored up about 50 yds down from me a few weeks ago, unfortunately I never saw the owner to talk to him about it, even though I had to walk past his boat 4 times a day!

Edited January 26, 2015 by MarkHez

[bargemast]

Harvest is moored up near my "local" at the moment, it is a wonderful if a bit strange looking boat, took my a while to work out which end was the front and which end the back to start with!

 

He was moored up about 50 yds down from me a few weeks ago, unfortunately I never saw the owner to talk to him about it, even though I had to walk past his boat 4 times a day!

 

I've never seen the boat in the flesh, and never met the owner, all I know is that he's a retired gentleman (now 78 years old) that wrote a blog while he was fitting out his boat, and that was interesting reading.

 

Peter.

[rustynewbery]

In June last year I organised a convoy of Russell Newbery powered narrowboats [along with 2 others] across the Mersey from Ellesmere Port to Liverpool. One of the boats was an Alvechurch ECO hull initially fitted with a single cylinder. The owner initially, and wisely, pulled out due to the fact he couldn't get decent headway on the Thames and he moors on the Wey. The upshot was he had a 2 cylinder retrofitted and he made the trip without any drama.

 

Talking to the marine surveyor who did our seaworthy certificates, the concept of such a bulbous front end did more to prevent the smooth flow of water and on the canal system was actually a barrier to headway.

 

Seemed like a good idea at the time, and very "green"

[onionbargee]

I have paper copies of all the original CAD drawings and some of the research findings for the hull shape research BW carried out.

 

The underwater bulb bows on ships has nothing whatsoever in common with it by the way.

[blackrose]

At the speeds most narrowboats travel I can't see an eco-hull making much difference in terms of fuel savings. The faster the boat goes, the "thicker" The water becomes and the greater the resistance. So perhaps on rivers where you can open it up and go faster it would be beneficial.

[cuthound]

If I recall correctly the hull shape was designed in conjunction with a university, and apparently reduces pressure and thus drag, on the bottom of the canal. One of the waterways magazines reported on it years ago and the article detailed the reduced pressure vs a conventional hull.

[Neil2]

Isn't it just common sense that you can't make much difference to what is basically a steel box just by tinkering with the front end.

 

I'm sure you could design a highly efficient boat for canal cruising that would need a fraction of the power most boats have, but as long as we insist on maximising internal space by having a flat floor and slab sides there's not a lot you can do. I'm not even convinced that long swims per se make a big difference, it depends on the overall design of the hull.

[IanD]

Most of the energy needed to propel a narrowboat hull on a relatively narrow/shallow canal is used up first pushing the water out of the way sideways (increasing hull cross-section), then moving it backwards past the hull (constant cross-section), then pulling it back in at the stern (decreasing cross-section). The first case causes a "hill" of water at the bows (otherwise the water won't flow sideways and then accelerate backwards), the second means there has to be a downwards slope to the water running back past the boat to move ot backwards, the third causes a dip of water at the stern (otherwise it won't flow back in again) -- in all cases the net effect is that you're going up a slight hill all the time, with canal water level raised near the bows and dropped near the stern -- this slope can easily be seen on a shallow/narrow canal.

 

Longer swims reduce the bow hill/stern valley by reducing the rate that water has to be accelerated sideways, so the water gradient and drag are less. If they also reduce the total underwater volume -- which they will if the draft is unchanged -- they also reduce the total amount of water which has to be moved backwards, which makes the overall hill you're climbing less steep. Anything else which reduces the rate of change of hull cross-section and the total submerged volume will also help, but as said above this all directly contradicts the desire for a flat floor over the longest possible length because long swims will intrude into the cabin at both bow and stern.

 

This is one good reason for having a mid-living-area layout with the kitchen at the rear (stern swim intrusion can be hidden inside cupboards) and a closed bow end with a lengthways double bed (bow swim intrusion can be largely hidden under the bed), though few boats seem to adopt this layout -- maybe because few hulls have long enough swims for this to be a problem...

[onionbargee]

Glasgow university.

[cuthound]

Thinking about what IanD said about water flow past a narrowboat, I wonder if XR&D's "Slipper" stern improves performance? They certainly steer well in reverse but you lose a lot of useful space in the engine hole because of the sloping floor and lack of conventional swims.

[IanD]

The so-called "slipper" stern will tend to pull more water from under the hull and less in from the sides because that's the way the taper is (horizontal for a conventional swim, vertical for the slipper stern), which I would have thought is not a good thing because it will cause more sitting down at the stern under power, and probably more pickup of debris from the bottom of a shallow canal.

 

(the extended "skeg plate" idea I asked about would do the reverse of this, but nobody replied...)

 

It also has an abrupt transition from the parallel hull to a straight taper, where a normal swim tapers in gradually assuming it's curved. If anything this would cause more drag -- if the "ramp" was curved and the hull cross-section changed the same as a normal swim this wouldn't be the case, but they're not built like this. Maybe it helps steering in reverse, but then many people say a long conventional swim does too.

 

I don't see the point of it; If if did have any big advantage then you'd think more boats would be built like this, but they aren't...

[Wessex]

I am starting to research the Eco hull for an electric narrowboat.  Were you able to gather info/data?  I would be very interested to hear how your project went.

[Muddy Ditch Rich]

X

Edited March 28, 2017 by Muddy Ditch Rich

[Wessex]

Hi, would it be possible for you to let me have a copy please?  Are they CAD files or pdfs?

[Wessex]

Muddy Ditch Rich said:

I have a copy of the original BW plans . They developed it in conjunction with Glasgow university. Then edited it to "X"! Would that be a "No" ?

[Muddy Ditch Rich]

20 hours ago, Muddy Ditch Rich said:

I have a copy of the original BW plans . They developed it in conjunction with Glasgow university.

Sorry, I think I threw it all away.