Mersey Ferry PS Claughton

[Paul TParticipant @pault84577]

Hi Dave

There was an experimental Mersey Ferry in 1817 called Etna which had a central paddle wheel between two hulls which was influenced by the Demologas design. But the dates given for Etna are 1817 to 1817 so it might not have been very successful.

Paul

[Colin BishopModerator @colinbishop34627]

I think the US Navy had quite a few monitor type vessels with inboard paddles where they were protected from action damage. I'm sure I saw a working model of one many years ago.

Colin

[Paul TParticipant @pault84577]

There were a few steamships around the early 19th century that had twin hulls with a central paddle wheel

This is Princes Charlotte built in 1816 at Pichelsdorf.

Two images of Castalia, September 1874. Launched in that year, for the English Channel Steamship Company, which later became a hospital ship.

Paul

[Paul TParticipant @pault84577]

Another update:

Mr Carsons collection of documents revealed that the board of Birkenhead Improvement Commissioners were worried about the potential damage to paddle wheels both during docking and occasional groundings so they were investigating different designs involving fully enclosed paddle wheels.

The experimental designs involving twin hulls and a central paddle wheel had proved unsuccessful and this type of design didn't offer any protection to the wheel during grounding.

The board were very interested in parts of the American design, namely the water inlet / outlet systems and the interaction with twin paddle wheels whilst enclosed within the hull.

They requested the shipyard to produce outline designs for such a ship which included a basic model.

I can't say for certain that the builders model that Dave photographed is the same model but it demonstrate all of the design details that a potential customer would be interested in.

The documents also contained rough concept sketches of the vessel which I am busy interpreting into meaningful drawings to see if the internal paddle wheel version could have ever been built.

Paul

[Paul TParticipant @pault84577]

What has always intrigued me is why the ferry companies were still using paddle wheels when the screw propeller had been in successful use since 1843.

It transpires that the Mersey at that time resembled a skip rather than a waterway and that floating debris was a common cause of damage to paddle wheels. The most common cause of damage or stoppage was rope and canvas being caught up in the paddle blades.

Whilst rope and canvas was fairly easy to cut free from paddle wheels they were very difficult and expensive to remove from propellers so the ferry operators preferred the risk of occasional broken paddle blades, which can be fixed 'on the water' to having a ship laid up in dry dock.

It was these worries about paddle damage that drove the investigation into fully enclosed propulsion.

One of the boards consultants was a prodigy of Brunel and he suggested using propellers enclosed within circular ducts running the full length of the hull and if this had ever been built it would have been the first ever application of a waterjet. But the board were still worried about rope and sail debris being pulled into the narrow water inlets so they dismissed the propeller idea in favour of the know costs of replacing damaged paddle blades.

Paul

[David WooleyParticipant @davidwooley82563]

One of the concept builders models of 1854 was the Clyde Ferry PS Alliance which was built and did function as a ferry but was this type of propulsion used , if so then perhaps , this method appears to be some sort of compromise ,as Paul has mentioned to reduce paddle damage . rather than try to conceal the paddles for protection a paddle which could move through 180 degrees ,

Dave Wooley

[Colin BishopModerator @colinbishop34627]

In good weather when the ship doesn't roll too much paddlers are remarkably efficient although a bit wanting in the close quarters manouevrability stakes. Before the last war you could do a day trip from Southampton to Cherbourg, stopping off at a couple of Isle of Wight piers en route to pick up and drop off passengers. In wartime they made excellent minesweepers and a number were lost this way.

Colin

[Paul TParticipant @pault84577]

Kevin

Having spent a few hours doing some desk work on this method of propulsion the first and major problem with fully enclosed paddle wheels, just as Colin surmised, is a build up of pressure within the paddle cases which would either induce hydraulic lock or blow the paddle cases to bits. Slots can be introduced into the paddle case sides which would maintain a stable atmospheric pressure both inside and outside the system.

The second problem is the enclosed system itself which theoretically will operate more like a water jet than a traditional exposed paddle wheel, there are allsorts of hydrodynamic engineering problems with a paddle wheel operating within an enclosed system which I am trying to resolve now.

Paul

[Paul TParticipant @pault84577]

Hello Kevin

Another quick update:

The inboard paddle wheels would work quite well in a boat up to 20ft in length but wouldn't have been able to provide sufficient power to move the Claughton.

The problem being that the paddles couldn't rotate fast enough without centripetal force pulling them apart.

If the paddles could be made stronger then the pressure created by the fast spinning blades would blow the paddle casings apart.

The conclusion is that if the inboard paddle version of the Claughton was ever built it wouldn't have worked.

However a 3 or 4ft model version would work very well and be a very challenging project to build.

Paul

[BanjomanParticipant @banjoman]

In othern words, a model that would be what our friends over on the plastic scale side of the model hobby call a "what-if" …

/Mattias

[Paul TParticipant @pault84577]

Hi Mattias

It certainly is a big what if and having read some of the documents I can see why the board were so keen to adopt the technology.

If it had been built it would have qualified as the first ferry powered by water jet.

I am still thinking about working up the sketches into a full set of plans.

Paul

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