How can I install a wheel in place of a tiller on my Tanzer 28?
Dan Dickison responds:
Thanks for your question. The good news is that your boat has an outboard hung rudder, so all the parts are more accessible than if you had a boat with a skeg-hung rudder. The bad news is that this is a pretty involved project, not impossible, but frought with details.
First, you'll need to make sure that there's sufficient clearance below your cockpit sole for the kind of steering system you intend to install. Because you have an outboard-hung rudder, you won't require much clearance down there, just enough for two small sheaves that will route the steering cables up to the axle on your wheel.
Steering systems can be engineered in a number of different ways, with hydraulics, cables, worm gear, and so on. For a boat the size of yours, the simplest approach would be a cable and chain-driven system. With this kind of system, the ends of the cables terminate on the rudder head, probably aided by a small quadrant on either side or a bar that pierces the rudder head. (The idea here is to gain enough leverage so as to be able to turn the rudder regardless of the amount of force exerted by the water.) Coming off the rudder head, the cables will lead forward and enter the hull through the transom—you'll have a couple of engineering options here—then continue forward until they run over the aforementioned sheaves and upward to the shaft that is attached to the steering wheel.
In most cases the cables are linked by a length of chain that travels over a sprocket which is affixed to that shaft. Everything above the cockpit sole is usually housed in a steering pedestal. Of course you'll have to make sure you've got room for the pedestal in your cockpit, and those considerations will also govern the diameter of the wheel you install.
Now, all of this might sound a little difficult to envision, and it probaby is, but don't worry. Get a copy of Nigel Calder's book The Boat Owners' Mechanical and Electrical Manual and you can begin to see what I'm talking about. He offers a fairly comprehensive overview of steering systems and their maintenance, along with a few useful diagrams. The other thing you can do is to check out Tom Wood's article called Steering System Spring Checkup, for additional information.
After you've looked at these two resources, you should better understand what you'll be working with and what modifications you'll need to make to your boat. One caveat here. Since I can only answer your question from my scant memory of the Tanzer 28 and the few drawings I have available, I recommend that you seek the advice of someone who has tackled this project before regarding the best approach for routing the cables through the transom. That's really the most daunting aspect of the modifications you're contemplating.