Originally Posted by colo.sail
I'd love to hear from someone who has done this, using designs found online or of their own making.
My boat is simple - stern mounted rudder
, tiller steer
Well, I did design and build one for our previous boat. After reading some books
and looking at existing designs I decided on an auxiliary rudder/trim tab approach. This boat (an old IOR one-tonner) was wheel
steered, and the weak point of the servo pendulum designs is in the attachment to the wheel
The final design I built was a blade rudder
, properly balanced, with a trim tab on its aft edge. All built from Plywood
, glassed over. Area about 1/3 that of the main rudder. Trim tab was actuated by push-pull cables
driven by an inclined axis wind blade, much like the Auto-Helm design. All pretty simple to build, if you can do the welding and simple machining yourself.
It took some fiddling around to get the rudder balance just right, but once that was done it steered quite well from about 5 knots apparent to storm force. We did 86K miles in that boat, and the vane steered approximately 75% of them. It broke twice -- once a pintle failure due to a corroded weld, once the rudder broke clean off when we had a big knockdown in a storm on the Tasman. In both cases our puny old Autohelm 3000
wheel pilot saved the day and got us in to a place where I could make repairs
IN your case, adding a trim tab to your existing transom hung rudder would be fairly easy, and building the vane part not impossible, depending on your skills and equipment
. Alternatively, I believe that Scanmar Marine
in Sausalito CA still makes the Auto-Helm vanes, and could sell you the upper parts
to drive your trim tab.
boat doesn't have a vane, and I miss it every time we go to sea. We have three separate a/ps and we've managed around 40K miles so far without being forced to hand steer when we didn't want to... and I still miss the vane!