The Kitchen Rudder

Kendall Carter

I am very old! Back when I was a midshipman at the Britannia Royal Naval College in Dartmouth, Devon in the UK, we had to learn how to drive boats. We learned all the basic techniques for handling power boats, as are admirably shown now in the Australian Boating Manual Chapters 8 and 24 and had to get our “tickets” on various types of power boats. One of these was the 32 ft cutter. These wooden clinker built ships’ boats were fitted to the larger Royal Navy (and Royal Australian Navy) warships from the second world war right up to the 1970s.

Most ships boats now are ridgid inflateables, and often twin screwed. The 32 ft cutters however were displacement craft, single screwed and propelled using a unique method known as the Kitchen Rudder. Though no longer used in modern boats I thought it might be interesting to explain how it worked. You never know, you might come across one some day. It took a bit of practice to get it right.

The Kitchen rudder system was patented by J.G.A. Kitchen in 1914 in collaboration with Isaac Storey.

Though often described as “Admiral” Kitchen, I can find no record of him as a Royal Navy Admiral. What we can say is that John George Aulsebrook Kitchen (1869 – 1940) (nicknamed Jack) was a remarkable British engineer, who lodged 175 Provisional Patent Applications, of which 118 were carried through to completion. He applied with Storey for UK Patent No. 3,249 on 7 February 1914 for a reversing rudder which was accepted on 4 February 1915. The idea was that the  unidirectional propeller rotated within the rudders, thus containing the slipstream. Boats could be reversed, brought to a sudden stop and have extreme manoeuvrability without needing to use a reversing gearbox.

It worked like this. There were two semi-circular “clamshell” plates fitted around the propellor which was always rotating ahead. Here is the diagram from an older Royal Navy Admiralty Manual of Seamanship.

The manual states that ‘Kitchen’ Rudder Boats “are the most maneuverable of all single-screw boats, and are more maneuverable than many twin screwed boats.”

The rudder consisted of two curved metal plates mounted so they encircle the propellor. (see diagram above). The movement of the tiller to port or starboard turns both plates to starboard or port respectively, in the same way as an ordinary rudder. In addition however, the plates can be closed together behind the propellor or opened out on each side of the propellor. This was done by a shaft which revolves inside the rudder post and was controlled by a wheel and worm gearing on the tiller.

Using another diagram from the old Admiralty Manual, we can see how it works here:

If the plates are nearly closed behind the propellor, the ahead thrust is neutralized by the backwash of the slipstream against the plates. Thus the boat is stopped though the propellor is still turning. If the plates are then fully closed, the backwash of the propellor slipstream against them overcomes the ahead thrust of the propellor and the boat is propelled astern.

By opening and closing the rudder plates the boat can be made to move ahead or astern at full, half, or slow speed or brought to a stop without the need for a reverse gear.

The boat is steered by the tiller as if fitted with a normal rudder, but when the tiller is moved the rudder effect is far greater and more effective at all speeds and the boat will therefore answer the helm readily at any speed including when stopped and when going astern. The manual stated that when turning at rest, the rudder exerts its greatest effect when the plates are fully closed, the tiller being worked as if the boat were going astern.

The speed of the boat (ahead or astern) was controlled either by the combined use of the tiller wheel and engine throttle, or by the tiller wheel alone with the engine running at constant speed ahead. When lying alongside stopped, the engine was usually throttled down to idling speed.

The Australian Historic Ships Volunteers (AHRV) have restored a cutter from HMAS Sydney at the Armfield Slipway in Goolwa, South Australia. The full details taken from the ARHV website are here:

“HMAS SYDNEY (III) Ship's Cutter

Vessel numberHV000648

Vessel Registration NumberVI 120 S

Date1940s

DimensionsVessel Dimensions: 9.75 m × 9.75 m × 2.74 m × 0.67 m (32 ft × 32 ft × 9 ft × 2.2 ft)

The clinker construction ship’s cutter may have been built at the same time as the ship it served with, the aircraft carrier HMAS SYDNEY. This warship was built in the late 1940s in the UK, initially for the Royal Navy but during constriction the ship was redirected to the RAN to fulfil one of two orders for RAN aircraft carriers. Navy documents have the cutter attached to HMAS SYDNEY in 1971 with the number 321458. At one stage its colour scheme was black topsides and white underneath.

The ship’s cutter served a multitude of small workboat and transport requirements for the aircraft carrier, almost exclusively in port. It was an open boat, and powered by a Dorman diesel engine. Instead of a rudder the steering system employed was the Kitchen method which redirected the flow off the propeller to steer to port or starboard, and also enabled the boat to move astern.

The Kitchen rudder (full name - Kitchen’s Patent Reversing Rudders), is a patented directional control system that suits slow speed craft. It was the invention of John Kitchen of Lancashire, England in the early 1900s. Instead of being a single ’vane’ rudder, it is a two part bucket configuration placed directly aft of the propeller that controls the direction of the thrust, and allows the engine to maintain constant revolutions and constant drive shaft rotation direction, while altering the direction of the thrust off the propeller.

The system consists of a pair of partial or half cones (‘buckets’) mounted on a pivot either side of the propeller with the long axis of the cone running fore and aft when the helm is midships. They are pivoted about a vertical axis and by manipulating how much each side is opened the vessel can change direction, and when completely closed the system is then directing the thrust forwards and pushing the vessel astern.

It required training to get used to, as the helmsman often had to look down at the controls to note the setting of the twin ‘buckets’ and adjust them as required, taking their eyes off where they were heading, and for some this was disconcerting.

The cutter was taken from the ship at an unknown date and transferred to the RAN Reserve cadets in Adelaide and used by them for many years. It was then bought by the Milang Historic Steam and Shipping Museum in 1993, and later handed over to the Armfield Slipway in Goolwa as a restoration project. It was relaunched recently and is in use at Goolwa SA.”

That is the only example I can find but I am sure there must be others still going.

The Kitchen rudder was a remarkable invention and was used in the navies of Britain, Australia, Canada and the USA for many years. I eventually managed get the hang of it.  Once you had mastered it you could manoeuvre the boat just about anywhere.

About the author:

Kendall Carter specialises in navigation, pilotage, and ship handling, and later served as Chief Instructor at the Royal Navy Navigation School. He commanded two warships, navigated the aircraft carrier HMS Ark Royal, and held key operational roles with NATO in Italy and the United States. Formerly the Queen’s Harbour Master for Portsmouth, he went on to hold senior maritime positions with the Royal Australian Navy and Transport for NSW. He is now a maritime consultant and a Fellow of the Nautical Institute.