Conversion from tiller to wheel steering

[Barry Smoger]

I am thinking of converting from tiller to wheel.I want to remain consistent with the wooden and vintage nature of the boat. An Edson conversion will not do, therefore. Anyone done this before? Is there a source of parts? (worm and roller?) I can fabricate the wooden aspects needed. Anyone tried to convert using an old steering box mechanism from vintage auto?

[Ian McColgin]

I've helped get rid of steering box units.

Edson steering - especially both the worm and the rack and pinion - have over a century of history each so may be 'authentic.' Certainly more than some hunk of iron from an old Dodge . . .

On Grana I made a cable system. Pretty simple. I have a nice 3' tiller arm under the aft deck.

Just cables from that around a drum on the wheel shaft.

Use the existing tiller and get some idea of steering stresses.

The pullys need to be strongly mounted and of nice diameter so's not to damage the cable.

Since the drum is not in plane with the rest of the rig, I have two pullys at the bottom of the helm box to carry the cables to the shelf&clamp. The run is fairly straight so from there I only needed the two dead abeam of the helm box on the shelf/clamp and two abeam the tiller arm.

If you think of the geometry just a little, you'll realize that it's nice to have the after pullys just a bit abaft the attachment on the tiller arm when it's dead amidships. If it's about half way from there to the fore&aft location of the attachment when the helm is hard over, then there will be the least slack in the system.

I had a bit of bronze prop shaft I threaded to take Goblin's old steering wheel and I turned the drum from some butcherbock I laminated up - about 8" diameter.

You may want to experiment at first. I wanted low stress on the cables - had originally had an edson wheel gizzy for the rudder post head but the lower leverage made for high stress on the cables, and more to the point, on the pullies. Ended up with a nice 1-1/2 turns amidships to lock, or 3 turns lock to lock. If your helm is heavey, make the tiller longer and/or the drum smaller. Just remember how the stresses multiply. The highly stressed edson cable gear you find in a pedestal steerer have a sprocket and chain to translate the rotation of the wheel and all the pullies are very highly loaded.

Depending on your design, you can have the rig variously exposed and can use fibre rather than wire.

A big transom hung outboard rudder might benefit from an external quadrent and run the steering lines out and behind.

There's no reason anything except the actually tiller head and pully sheeves need to be metal.

G'luck

[ 09-11-2002, 12:15 PM: Message edited by: Ian McColgin ]

[Adam C]

Try these guys for hardware - real vintage stuff

http://www.lunenburgfoundry.com/steering.html

[Thaddeus J. Van Gilder]

I sailed on a 1883 barquentine with the original edson worm gear..

what , doyou think their stuff is modern?

I have a new bronze edson pump that could be 100 years old...you just can't tell.

[Barry Smoger]

Thanks for the comments. No intention of disparaging Edson...I am referring to their current product line. Is there, within their offerings, a source of appropriate parts or mechanisms for a vintage boat?

[JimConlin]

Edson offers a shaft-sprocket assembly which you can bolt into a box of your devising. With it the rest of the Edson cable-steering system components can be used.