A voice crying in the wilderness?

Saturday June 14, 2014 Written by Ken Kingsbury Published in Weekend
Treddlecat inventor Ken Kingsbury has plans to take his treddlecat concept to the open ocean with a larger passenger vessel. 14060901 Treddlecat inventor Ken Kingsbury has plans to take his treddlecat concept to the open ocean with a larger passenger vessel. 14060901

The technology employed by Treddlecats - a common sight in Muri lagoon - could soon be ploughing through the high seas.

That's if Ken Kingsbury can realise the bold plans he has to take his invention to a grander scale. Kingsbury wants to take the propulsion technology used by Treddlecats and develop an “ocean powered” vessel that could potentially be used to ferry passengers back and forth to the outer islands. Here, Kingsbury describes the challenges he’s up against, and what it will take to realise his vision.

Throughout the history of mankind water has been a natural barrier. If it was too deep to wade through or too wide or fast to swim across it meant that a boat of some sort was needed.

At first the only way to propel a boat would have been to push the water the other way with hands or later with paddles of some sort.

Later still it would have been found that the wind could be harnessed with animal skins or woven cloth held out to catch it. This would have been the origin of sailing.

When confronted with a stretch of water where the other side was out of sight the brave sailors accepted the idea that the necessary propulsion would have to be sails and/or paddles (oars).

As the boats became bigger they were called ships and oars were only used for the small boats they carried for convenience.

Both the sails and the sailors became more sophisticated to the point that these vessels could travel in the opposite direction to the wind while still using it.

Over the thousands of years covered by the process so far the sophistication reached the point that in the recent racing for the Americas Cup a 25 kt wind one way could be made to propel the boats at 30kts in the opposite direction.

But it was an extremely elaborate sailboat and almost unbelievably expensive to make.

Let’s go back to the point when the first sailors considered crossing an ocean.

If they’d had a team with half the knowledge and innovation capacity of the team who produced the latest racing yachts they might have realized that the energy stored from the wind in the waves could more easily be extracted and be a more reliable and cost effective way of propelling a ship.

Everyone experienced at sea is aware of the mighty power of waves but let’s consider the following two comparisons


1. Water is about 200 times heavier than air so it’s likely that the equipment to extract some of this energy will be much smaller than a spread of sails.

2.  Waves, especially ocean ones, do not change so unpredictably or so much in amplitude whereas winds are fickle by nature and can rapidly become destructive without warning. When they are light even the most elaborate spread of sails is not enough. At the opposite extreme the smallest and strongest sails can be ripped away in a second.


As a small boy I made model sailboats and dreamt of making my living with bigger ones.

A career in aviation coupled with a passion for sailing taught me a lot of useful understanding about fluid dynamics.

Throughout this half century I have been absorbing peripheral knowledge and innovating ways of using it. Further understanding came through my struggles to make the many different devices I dreamt up. Satisfaction came through being able to use them.

For example I sprayed thousands of hectares of crops in NZ and UK using spray gear I designed and made myself mounted on the helicopters I used to fly. Later I designed a windsurfer which won the UK open windsurfing champs in 2000, so my guesswork couldn’t have been that far out.

Over the last few years I realised that I could be in a unique position to solve one of the most pressing problems of our age. How to power ships without burning any more of the liquid fossil fuel that will all be needed for aviation, (everything else can be run on alternative energy).

While developing the innovative toys I have made called Treddlecats it suddenly occurred to me that this was the perfect layout for a wave powered ship.



Large catamarans are prone to breaking up at sea because the two hulls are always trying to move in different ways. Eventually the structure gets fatigued and fails.

All that is needed is to design the structure so that the hulls can move differentially and then reduce their movement by extracting the destructive energy that would otherwise break the uniting structure.

The treddlecat even has the ideal propulsion system to use this energy. The laterally swinging foils are much more efficient than water screws and much simpler to make and maintain. They also don’t need any rotating components or seals.

But here comes the biggest advantage apart from using no fuel.

The passengers could travel in a central carriage similar to an airliners fuselage which could be held steady by the computer controlling the energy extracting machinery, effectively isolating it from the two pitching hulls.

Over the last few years I have built up a fairly complete picture of this new ship and have some ball park figures of how it could perform if properly designed and constructed.

The first working version could be 24 metres long with a keel spacing of 12 metres and should be able to cruise in ideal conditions (2 metre swells) at 12 kts. It should be able to carry 60 passengers and a ten ton container on each hull (the extra weight would generate more power).

Don’t ask me how much it would cost to make – that’s a bit like asking how much it would cost to make the first aeroplane in year 1900. Apparently the Wright brothers were advised by their bank manager to stick to making bicycles.

What a good job they didn’t take his advice!


I would be delighted to discuss this project with anyone who could help lower the incredulity barrier that has so far kept the investors away.

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