National Maritime Museum floats mystery boat

Can you help us identify this very strange boat? It has 2 odd paddle wheels and one idea is that it was a canal dredger!

Boat model in National Maritime MuseumThe National Maritime Museum have asked if we can help them identify a boat model they have in their collection. They have classed it as ‘an experimental paddle vessel’, but wondered if the purpose of the boat might have been to dredge canals and move silt around. It doesn’t look like any type of dredger we have seen, but then it doesn’t look like the ‘paddles’ could be for propulsion either!

The model is thought to be Victorian, an iron and wood prototype about 700mm long and not intended to be operable, not least because the hull would obviously not be watertight. You can see a description and full size photos of it in the NMM online catalogue.

The boat has two paddle wheel assemblies but these sit inside the hull, not outside it. The bottom of the model’s hull is open, so it is possible that the intention was for the boat to operate semi-flooded, possibly kept afloat by bouyancy in the two raised ends. Alternatively this could simply be a ‘cut away’ model to show the operating mechanisms and a completed craft would have a watertight ‘floor’ above the paddles.

Boat model in National Maritime MuseumHowever the questions don’t end there! Even if the boat could be persuaded to float, how would the paddle wheels operate? The model has a central mast to which are attached two hand cranks, connected through a small gear to a larger gear and then by connecting rods to two vertical levers. The levers are hinged at the top and get pushed out and back by the connecting rods. So when the cranks are turned the levers slowly push the paddle wheels fore and aft along rails in the bottom of the boat. The paddle wheels are not directly rotated by this lever movement, but they do have geared outer rims which could create rotation if the rails were also geared.

So turning the hand cranks would produce a backwards and forwards motion of the paddle wheels, possibly also rotating them. But what sort of movement of the vessel would that produce? There doesn’t seem to be any mechanism for ‘feathering’ the paddles when moving ‘back’ so could the boat do any more than just bob up and down?

And finally, there’s the rotating mast! You can probably see in the top photo that the hand cranks also drive another large gear which engages with a crown gear to turn a vertical rod. This rod forms a kind of mast for the vessel and at the top appears to be shaped to take some sort of fixture. There looks to be another lever which could be used to manually disengage the crown wheel to stop the rotation.

So we need ideas!

  • Could the paddles be intended for propulsion? Why slide them fore and aft rather than simply rotating them? And how would they produce any synchonised forward movement?
  • Could it really be some sort of canal dredger? The paddles might stir up soft silt, but they wouldn’t move it anywhere!
  • Or might it be a vessel intended to operate in marshy waters, so it would use the paddles to crawl across the top of mud, which might explain their sliding motion.
  • But then there’s the rotating mast, why is that needed?
  • The vessel’s shape looks a little like a lightship. Could the motion of the waves and tides turn the paddles which rotate the mast which would have had a (missing) light on the top. Those hand cranks could be a bit of a red herring!
  • Also there’s a history of experiments with sailing vessels with masts, or turbines on the masts, rotated by the wind which then turned paddles or propellers to propel the boat, directly into the wind if needed.

The Museum is asking for our help, please make suggestions either below in our Comments box or on their Online Collections page where you can also see more detailed images.

Our thanks to the National Maritime Museum for this information, permission to reproduce their photographs and for making us think!

All materials and images © Canal Junction Ltd. Dalton House, 35 Chester St, Wrexham LL13 8AH. No unauthorised reproduction.

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