Kitchen Rudder

[clifonef]

Most recent WB had article on Gertrude, a displacement hull with a kitchen rudder. I can't find any discussion in this forum on the idea.

I have built a boat with the idea that I may want to use this concept, mainly to improve control. With a light boat, a big prop and more power than I should have installed, forward idle is 5 knots, and you need to be holding onto something when you put it in gear.

I have been trying to figure out how to install controls other than the tiller/crank, and I think hydraulic may be the answer. Could one use a hydraulic ram on the tiller connected to another ram on a lever to achieve this (no electric, just hand power)? If more leverage was needed, could make it a screw connected to the control ram.

Re: How to design it adequate for forces involved. My thought is to make up a closed clamshell of the appropriate size, throw it overboard attached to a big, stiff spring (or a scale if one could be found), accelerate to top speed, measure the deflection, and then find out how much weight is required to deflect the spring that amount. This would be the base load, and then of course I would double it.

Re source of small hydraulic items. What would be a good source of smallish used hydraulic parts. Bigger than those on 9" drum brakes, smaller than those on a farm tractor?

Lastly, why no discussion on a kitchen rudder? Too wierd, too complicated (certainly reverse on a transmission is more complicated), or is there something I'm overlooking?

Thanks.

[rbgarr]

Good luck with the project.

[Figmental]

Here is a source for new hydraulic stuff that has the best prices I've found. Why buy used? Surplus Center (http://www.surpluscenter.com/)
A big boy, big toy erector set store. Good luck!
David

[G. Schollmeier]

Many years ago my first post on this forum was about the Kitchen rudder. It is long gone; I haven’t been able to pull it up. You can read a large amount of info on the subject at boatdesign.net, here is the thread. http://www.boatdesign.net/forums/showthread.php?t=418&highlight=Kitchen+rudder
There is a lot of stuff there, including a drawing for a hydraulic setup.

Gary :D

[G. Schollmeier]

I just reread that whole thread for the first time in a while. It seems you already have been there. For myself I can say I have not completed a full size working model, but I am still interested in this rudder.

Gary :D

[Hwyl]

I remember they had one of these at a Naval school, near where I grew up.

From this http://www.hmsconway.org/relics_artifacts.html page, I pasted this:

The pinnace was part of her inventory and was given to Conway.

The pinnace seems to have been one of standard class of Kriegsmarine small support boats. Wartime footage of other raiders including the famous/infamous Atlantis and Pinguin clearly shows sisters to the pinnace being used to ferry men and materials between vessels at sea. Old Conways have reported first hand experience of similar boats given to the Holyhead and Liverpool Pilots. Another sister boat was operated by the German police out of Cuxhaven and an identical boat used to lie on the mud at Portsmouth Hard for years, but is no longer there. If you can provide more information about these boats we would be most interested.

"When the pinnace was delivered to the ship in 46 by sea from Birkenhead she still had her original engine and transmission, timed in both directions over a measured mile between Gallows Point and near the Gazelle her speed was 11.5 knots. She had I think a Mann diesel and conventional transmission, the "gear stick " was rather like and old hand brake lever with a release that locked it in position. There was a plate on the E/R bulkhead which said in German that it had a capacity for 85 persons in fresh water. In 1950 as a callow 3rd mate leaving Hamburg in the Dymas we had to radio ahead to Cuxhaven to request the police to collect some stowaways, the police came out to meet us in the twin of the pinnace! On the pinnace it was possible to see where lifting points were fitted so she could be lifted on davits."

When delivered to Conway she had a conventional rudder. In 1949 or 50 she was fitted with Kitchen Gear, more correctly ''Kitchen's Patent Reversing Rudders'' It was patented in the U.K. and Abroad under British Patent 3249/1914 ( Which may have been reference to the year ) by Gordon H.Fraser 747 The Liver Buildings, Liverpool. The modern steering unit by waterjet is a derivative. This made her very maneuverable. The following is an extract from "Basic Naval Architecture" by Barnaby:The Kitchen rudder consists of two curved blades carried on pivots above and below the propeller. Normally, the blades lie on either side of the propeller, but they can be angled to the race to give steering effect, or they can be closed together behind the propeller to form a sort of hemispherical cup that enables astern way to be obtained without the necessity of reversing the propeller. This may sound like "hoisting yourself up by your shoe- strings", but there is an actual astern thrust of the order of one third of the normal amount. This suffices for ordinary maneuvering as the closed blades provide an efficient brake.” Other settings allowed quick and fancy maneuvers. Cadets who could master this complicated arrangement (many failed miserably) could do anything with the pinnace! “I found that especially when stemming the tide that by using the kitchen gear/rudder the boat would very near go sideways. Great fun and when executed with some panache, then very spectacular coming alongside. When driving one of HM Minesweepers later in my career the previous experience stood me in good stead, Happy days!!”

"The starting routine even more special. There was a long steel lever that had to be cranked back and forth to build up pressure in the firing cylinder, which would then be released by pulling upwards on a short handle at the side of the engine. In cold weather liberal applications of ether spray were also required."