High-speed rudder design

[Morgig]

I have been looking for papers or information on the design of high-speed rudders, particularly wedge type rudders, without much success. I have done a general search of the internet and the SNAME web site; however most of what I’ve found is on ship or sailing yacht rudders. Does any one have any useful links or papers on this subject?

The other subject that I am also currently looking at, is the design of propeller tunnels, particularly inflow at the fwd end. Again if any one has any links, papers or useful comment I would be grateful.

Morgig

[SailDesign]

Morgig - try to fiond a copy of Peter du Cane's book on High Speed Power craft. Plenty of rudder design stuff in there, and you're in the right country to (maybe) find one in a library.
Steve

[Morgig]

Thanks Steve, yes Du Cane's boat is a great source of imformation on high-speed craft in general, I have access to a copy at work. However I was looking for any other sources of information. I'm sure that out there there is some interesting research done on the subject of high speed rudders, done in the past 40 years since Du Cane's book was published. There seems to be lots of information available on ships, yachts etc, but seems to be a bit of a hole when it comes to the design rudders for high-speed craft.

You are lucky to day. Do a web search of ACBS . The " Antique & Classic Boat Society ". look for a Chapter in your area to contact owners. The racing hydros are ALL using wedge rudders with ram water pick up cooling tubes built in. They Do it at +140 mph and turn sharp. Not too much theory as they really are masters at that type of racing. They are very open about the knowledge. If you meet Clams, post me.

[Vincent G]

You can refer to 'Rudder Design for High-Performance Boats' by Dnald L. Blount & Dudley Dawson - published in Professional BoatBuilder Aug/Sep 2002.
This article contains references to other articles.

Best regards

VG

Morgig. What speed range, low to hi are you looking for? Turning? Size range of boats?

[Morgig]

Richard
This is a general enquiry about high-speed rudder design, however I would say that anything operating at 30/35 knots plus would be interesting, with hull lengths ranging from 7 to 25m. Not sure what you mean by "turning?" please clarify.

It sounds like you are into cruisers that need tunneled propellers. I view them as a partial admission of powerboat companies that tugboats know more about prop efficency they they do. Long over due. A tunneled prop, is in my opinion, operating as a 1/2 completed KORT NOZZLE. Somebody may even invent the fact, that Torque is what moves cruisers. Tugs have more efficent use of their engines power than any yacht ever will. Have to- they operate as a business. If you want modern advice contact Kort Nozzle manufacturers. Real eye openers. They include a compatable rudder set up.

[Morgig]

I work mostly in the commercial sector and a lot of our higher speed boats are water jets for a combination of reasons. However sometime our clients want prop driven high-speed low draught vessels and cavitations at the fwd end of the tunnel can become a problem. I am therefore always on the lookout for any new work/ideas in this area

Looking at a tunnel as ½ a Kort Nozzle is an interesting idea and we see where that leads me.

One of the ideas I was interested in was warping the tunnel fwd of the prop so that it intercepts that hull to form straight edge, similar to a waterjet tunnel. I believe the RNLI have been work on this and I am interested to see if any one else has done any work in this area