Twin rudder trouble?
Q
I have been sailing for about 30 years and have been an RYA Yachtmaster Instructor for 15 years. My reason for writing is that during courses I spent a reasonable amount of time teaching the benefits of prop wash and prop walk to aid manoeuvring in close-quarter situations and the use of prop wash to spring the bow off and back to the pontoon under control. I would also come alongside using a bow or midship spring or stern line and use prop wash to hold the boat in place.
During this time I have always sailed or taught on yachts with a single central rudder. I have noticed that a number of mid-range yachts are now coming on the market with twin rudders (see your new boat test in the March 2019 issue).
This led me to think that a lot of what we teach needs to be modified as we will no longer have prop wash passing over the rudder and will need to rely more on momentum to make our turns. I thought this might make for an interesting article in future issues as it is a consideration when buying or chartering.
A
James Stevens replies: Twin rudders are positioned well clear of the propeller so using the wash from a burst ahead cannot be used to turn the boat with the helm hard over until there is forward motion. The downside of this is most noticeable when turning in a confined space when it’s really useful to rotate the boat without going ahead.
Modern twin-rudder boats are light and responsive to small movements of the rudders so even without the prop wash they will turn pretty readily, but without a bow thruster it’s difficult to turn in a boat length. The stern of a twin rudder boat can be sprung off on a headspring but not so effectively as a single rudder because the rudder makes little difference. When springing back into the dock with the prop engaged ahead, the spring has to be secured aft, unlike a single rudder where a line forward and the helm steering away from the dock will bring the stern in.
With twin rudders, because there is no forward motion and no prop wash effect, the rudder makes no difference. It’s much simpler than trying to manoeuvre a longkeeled yacht out of a tight space under power on a windy day, however.