Mr Hotchkiss' hydraulically powered river launches....

[davidwheeler]

In 1921, just a few years before his Cone invention burst upon the world of marine propulsion, Mr Hotchkiss, through the company incorporated for that very purpose, produced a new system of propulsion by water jet, which he named the Hotchkiss Hydraulic Propeller.

 

Technical details of this system, if you are interested, are to be found in Engineering Jan 4 1924 pages 13 and 16, but a short description, taken from Motor Boat's report of the 1922 White City boat and leisure show, will perhaps be enough.

 

Some Hydraulic Propellers were fitted to a few small vessels, and several were sent abroad, but its success was not immediate. Mr Hotchkiss then designed and had built a series of shallow draft river launches with the system, which he claimed were suitable for rivers such as the Thames and the Severn and others. These launches did achieve some sales and I have included details of a few of them below, taken from the Motor Boat. The illustrations and descriptions speak for themselves, but it is worth mentioning  in particular the launch 'Torfrida'. The reports state that this was built to the order of Mr George Cadbury Junior of Birmingham. Mr Cadbury was a firm supporter of canals and inland waterways. He was the co-author of the Pitman's Transport Library's book on the subject of canal transport. But I have found no mention of the boat's use by Mr Cadbury, or how and if at all he used it on the Upper Severn. So we cannot gauge how successful the boat was, or how any of the Hotchkiss launches were used, and for how long and of what became of any of them.

 

Despite the support from such an eminent gentleman of the time, the Hydraulic Propeller was not a success. Not because it didn't fulfill its claims, there is no evidence of that, but because of its complexity and its cost. The company failed after a very few years, and Mr Hotchkiss struggled to settle its debts. As he acknowledged, without sufficient orders, the production costs were too high and without sufficient numbers, could not be brought down to a competitive level.

 

He had better luck with his Cones.

[David Mack]

Elegant craft, but the articles don't really describe what the hydraulic propellers actually are (and how they differ from the later cones).

 

Back in the early to mid 70s there was a company Tough Boats which built small steel boats at the Oldbury Pumphouse on the Titford Canal. Options included 'water jet propulsion' said to be ideal for shallow and weedy waterways, but I never saw one and I don't know if any were actually built or how they performed.

[IanD]

1 hour ago, David Mack said:

Elegant craft, but the articles don't really describe what the hydraulic propellers actually are (and how they differ from the later cones).

 

Back in the early to mid 70s there was a company Tough Boats which built small steel boats at the Oldbury Pumphouse on the Titford Canal. Options included 'water jet propulsion' said to be ideal for shallow and weedy waterways, but I never saw one and I don't know if any were actually built or how they performed.

Water jet propulsion works well for high-speed boats, which is why the fast catamaran ferries use it -- anyone who travelled over to France on one (Condor?) probably remembers the huge rooster-tails at the stern when zipping along at 40+kts or so -- or 50kts in the newest fastest boats.

 

https://www.wartsila.com/media/news/23-07-2013-the-world's-fastest-high-speed-ferry-is-powered-by-wartsila-axial-waterjets

 

They don't work for slow-speed boats because to get maximum thrust you want a high-speed jet of water, IIRC ideally ejected backwards at double the boat speed through the water for best efficiency. So throwing relatively small quantities of water backwards at 80-100kts works well for these, but is inefficient for slow-speed boats (<25kts or so) where propellers are better.

 

https://www.dmsonline.us/waterjets-when-to-use-pros-and-cons/

Edited September 5 by IanD