Converting linear tiller autopilot to wheel steering.

[Stormboy]

I am hoping to save a few dollars by converting my linear drive
autopilot to operate wheel steering .
It may or may not be possible ! but on paper it looks like it might work using pivoting and swivelling joiners. My wheel steer is very light and easily driven, just wondering if anyone out there has tried it or have any positive suggestions on the best way forward.
Thanks for your thoughts , drawings or ideas.

[RaymondR]

If you don't mind a bit of agricultural it's not hard to do.

The image shows an electric drive bike, 24V DC motor driving an auto timing belt, driving a Regal cookware frying pan, driving the wheel steering on a 40' steel boat.

The head was from a Raymarine ST4000 wheel pilot. I threw away the original plastic wheel drive part because it used to chew up the flimsy 7mm toothed belts at $40 a time and it also had flimsy little nylon gears in the gearbox.

I only used one auto timing belt in about 12 years because the first one perished in the sun

[Stormboy]

Originally Posted by RaymondR

If you don't mind a bit of agricultural it's not hard to do.

The image shows an electric drive bike, 24V DC motor driving an auto timing belt, driving a Regal cookware frying pan, driving the wheel steering on a 40' steel boat.

The head was from a Raymarine ST4000 wheel pilot. I threw away the original plastic wheel drive part because it used to chew up the flimsy 7mm toothed belts at $40 a time and it also had flimsy little nylon gears in the gearbox.

I only used one auto timing belt in about 12 years because the first one perished in the sun

Thanks for the input, it looks solid enough, but I need to use a
linear drive autopilot, that is typically used with a tiller, and
then convert the linear action into a rotary action to turn the wheel.
Anyway .....thanks for your interest...

[chris95040]

If your steering is very light, maybe it implies a low gear ratio between your wheel and rudder, in other words, a lot of wheel turning for a little rudder motion.

Just using direct linkages as you describe, I imagine you’ll only get, at most, a little under 180 degrees of wheel rotation, or 90 degrees to port, 90 degrees to starboard. Does that equate to enough rudder motion to control the boat? I bet the answers is, ‘sometimes, if the sails are balanced and the sea state isn’t too bad’.

I also think the response will be too slow unless you carefully consider where you attach to the wheel. Ordinarily the unit’s fully extended to fully retracted state is associated with a broad range of rudder angles. You probably don’t want to require the drive to move through its entire linear range to access the limited range of rudder angle you are making available to it.

Can’t you mount it below? Attach a little tiller arm to your rudder post under the cockpit?

[stormalong]

The original Tillermaster, the granddaddy of all tiller autopilots had a wheel adapter available. It was basically just a pin on an arm which you set the Tillermaster drive on. It is easily made. The issues are leverage and movement range. The closer to the wheel center means more range but provides less force. As you move farther from the center the range goes down but the force increases - just like any other lever.

[Pete7]

Storm boy, what make and size of boat do you have?

Do you have access to the top of the rudder shaft from the cockpit?

Pete

[Paul Howard]

I am also interested in this, as I am in the process of converting my 37ft. catamaran from tiller to wheel steering and have a Raymarine 2000 set up that works well on the tiller. The new wheel is 38" diameter and I am thinking of doing something similar to what is suggested by Chris 95040.

The linear drive tiller pilot will not work below deck as it does not have a clutch but must be lifted on or off the pin when engaging or dis-engaging, and is not practical unless you have a hatch over the quadrant or tiller bar on the rudder shaft and can reach it from the cockpit. On my boat that is not practical as the inboard rudders have a cross-over bar and quadrant well enclosed and out of reach.

I have been thinking of all this, too, and will experiment next summer with a set up to try to get the distance of the pin from the wheel hub just right.

[Quadrille in JB]

I had a simrad tiller pilot that I would connect to my emergency tiller with a pin. It worked flawlessly on several crossings. I just had to lift the pin off off the emergency tiller to use the wheel.
This is a very inexpensive AP solution.

[olaf hart]

If you could get your hands on a wind vane autopilot and fit that to the wheel, the tillerpilot would also work fine on that...

[warrior 90]

Originally Posted by RaymondR

If you don't mind a bit of agricultural it's not hard to do.

The image shows an electric drive bike, 24V DC motor driving an auto timing belt, driving a Regal cookware frying pan, driving the wheel steering on a 40' steel boat.

The head was from a Raymarine ST4000 wheel pilot. I threw away the original plastic wheel drive part because it used to chew up the flimsy 7mm toothed belts at $40 a time and it also had flimsy little nylon gears in the gearbox.

I only used one auto timing belt in about 12 years because the first one perished in the sun

I like Your agriculture version. Makes a lot of sense even for deep sea fishing ....spares are easy to come by even so it looks like this set up will last a live time. Will be thinking about a deluxe version.
Yes, You are right...... the Raymarine is a little flimsy and set up for screwing the cruising kiddy with constant spare parts concerns.
How are You doing on the energy side ?
Of course a reliable helms man is a little more hungry but I would like to know about Your experience on average ?
Did You have to make any other modifications on the ST 4000 as far as to the electrics / wires ?
I asume with a 250 watt bicy motor and decent gear ratio this thing will last forever. I like the concept of the wheel drive,
Cheers

[Stormboy]

Originally Posted by stormalong

The original Tillermaster, the granddaddy of all tiller autopilots had a wheel adapter available. It was basically just a pin on an arm which you set the Tillermaster drive on. It is easily made. The issues are leverage and movement range. The closer to the wheel center means more range but provides less force. As you move farther from the center the range goes down but the force increases - just like any other lever.

thanks for that , I googled and found an old ad on Cruising World with a pic of the old Tillermaster wheel adapter, seems pretty simple...
so I will give it a try, luckily my vessel has a long keel and tracks well, and as I only need it for longer ocean voyages it needs to make minor adjustments only, so hopefully this system should work ok.

[stormalong]

Originally Posted by Stormboy

thanks for that , I googled and found an old ad on Cruising World with a pic of the old Tillermaster wheel adapter, seems pretty simple...
so I will give it a try, luckily my vessel has a long keel and tracks well, and as I only need it for longer ocean voyages it needs to make minor adjustments only, so hopefully this system should work ok.

I'd like to see that old ad. can you post a link? Thanks.

[RaymondR]

Originally Posted by warrior 90

I like Your agriculture version. Makes a lot of sense even for deep sea fishing ....spares are easy to come by even so it looks like this set up will last a live time. Will be thinking about a deluxe version.
Yes, You are right...... the Raymarine is a little flimsy and set up for screwing the cruising kiddy with constant spare parts concerns.
How are You doing on the energy side ?
Of course a reliable helms man is a little more hungry but I would like to know about Your experience on average ?
Did You have to make any other modifications on the ST 4000 as far as to the electrics / wires ?
I asume with a 250 watt bicy motor and decent gear ratio this thing will last forever. I like the concept of the wheel drive,
Cheers

I don't know what the power draw was having never bothered to measure it. I just assumed that by running a 24V motor at 12V the wattage would be halved and the current draw less than about 12 amps. Having had to replace one of the MOSFETS in the H bridge output I was aware of the type and the current draw was well within the devices limit.

The system worked very well except that the motor turned out to be poorly sealed and the field magnets on the first motor lifted away from the case. I had purchased two and disassembled the second and re-assembled it with a good quality sealant. The motors included a reduction gear and only cost about $100 so the loss of the first was not a financial disaster.