I think that wheel steering
is quite do-able, but the difficulty in fabricating a wheelstand and pedestal
, as well as a wheel
makes a store - bought unit very attractive!
I designed a system for a custom boat that had no underdeck access to the rudder
shaft, and needed the wheel right over the rudder
It came out beautifully, once we calculated the rudder torque. After we calculated the mechanical ratio of the lever system we could then find the rim load on the wheel, and now Moondance has a beeeeyoodiful mechanical steering
, so light that moving the rudder when she's out of the water
makes the wheel spin.
Eat that cold, all you nay-sayers and open-wire and transmission-steering enthusiasts!
But the real witch-doctoring came down below.
I took an Edson
and ran the linkage out to a bellcrank under a custom-fabricated footboard/arch with teak
slats. This means that the helmsman can snug down on the low side, or ride the rail on the high side whilst still having a level floor underfoot.
You can just see the arch behind the mainsheet traveller in this photo
The issue which I overcame was the misalignment of the rudder stock. You can see that the vertical axis of the draglink is rather skewed against the head
of the stock below it: fine for a tiller but impossible for a pedestal.
There are many arguments in both cases, but wheels are comfortable to use, and they give a range of steering positions, but the real advantage of a mechanical system like this is the Ackerman effect which you won't get with straight transmission
in dead-ahead position, the rudder does least work but has greatest effect, so with the levers set to maximum radius, the return for effort is max. As the rudder approaches max deflection, the force it transmits approaches max, but the levers are working at minimum radius at that point. Don't ask me- draw it! At max rudder angle any helm
command produces minimum rudder change, but maximises the force.
Simple, but very effective!