Rotary Autopilots, Need Advice!

[EvermanJ]

Are there any rotary (chain driven) auto pilots that do not require a costly core pack? is it possible to just get the drive unit and a head?

my rinky-dink st4000 head unit just fried, and am now stuck on the north end of Tehuantepec one month before hurricane season. i have a sailboat that weighs 13 tons. the boat was originally rigged for a rotary because there is a gear in my linkage where one used to be. im in bit of a bind if anyone has any help. my only other option is to get another wheel pilot, but, as i already know, i need something stronger.

[44'cruisingcat]

Check e-bay. you can certainly buy Raymarine control head units seperately. I've seen plenty of hydraulic drives available, wasn't looking for a rotary drive, but expect you'd find them.

[EvermanJ]

ive been looking on ebay and the only rotary drives i can find are the raymarine, which is nice except i think they need the core pack to work which is an extra 2k. can you confirm wheather or not these drives rquire the core pack? id like just the drive unit and head.

[atoll]

i have a 1/2 hp chain drive unit that im able to run with my st 3000.

but and that is a BIG BUT the motor has solenoid switches to run off 24 volts and high ampage,also to reverse pos to neg and vice versa,so as to reverse the motor.

the st 3000,does this automatically by reversing pos to neg,but at 12 volts and at a low current,so with the aid of 4 diodes i am able to use this to control the 24v solenoids,and thus control the big auto pilot.

but normally we are just using it as a heading unit for the belt driven st 3000 auto pilot,which steers our 63ft yacht in seas up to about 1.5 m down wind and with no problem at all up wind in all conditions.

a friend of mine has sailed his 36 ft,then 55ft and up untill recently his 71 ft catamaran with out any auto pilot,just by getting on course and ajusting the sails to balance the tiller which has an elastic and block and tackle on the wind ward side which as soon as the sails flap pulls the tiller over and powers up the sails again.

might be cheaper to find some crew.....best of luck

[ShaunJ]

CPT Autopilot Inc.
I believe this is the best wheel autopilot in the market today. These are installed on some very big and heavy boats. They are worth a look if you can't find what you are looking for.

[atoll]

Originally Posted by EvermanJ

ive been looking on ebay and the only rotary drives i can find are the raymarine, which is nice except i think they need the core pack to work which is an extra 2k. can you confirm wheather or not these drives rquire the core pack? id like just the drive unit and head.

for the drive unit to work you will need a head unit,core pack,gyro compas and rudder transducer.

un less you use the system i explained before,ie st 3000/4000 control unit with diodes and solenoids

[atoll]

hi basically you need 4 diodes and 4 12v solenoids.

from the st 4000 to the old motor the 2 wires to the drive unit are pos/ neg in on direction, then neg /pos in the opposite direction.

each wire you need a 2 diodes,one allowing pos to pass and one allowing neg to pass.

now you have 4 wires,that will alternate between pos /neg turning right and neg/ pos turning left.

these now act as relays to the 12 volt solenoids.
solenoid 1 and3 are pos and solenoid 2and 4 are negative thus reversing the current direct from the batteries.

will draw a circuit diagram hopefully that makes sense.

[atoll]

slight correction to the wiring from diode to solenoid 2+3,incorrec in first photo,this one is correct,top right is the drive unit

[olaf hart]

Originally Posted by atoll

slight correction to the wiring from diode to solenoid 2+3,incorrec in first photo,this one is correct,top right is the drive unit

Great stuff, but I find it difficult to understand the second wiring diagram.
The leads from the control unit seem to go to the solenoids, but not the terminals.
The first one was easier in a schematic form, any chance of posting a modified schematic diagram?

[atoll]

the square boxes and round boxes denote the switched pos/neg feed from the diodes and control unit in the 1st diagram .
view the second diagram starting from where the heading unit feeds in to the 4 diodes and terminates.

the correction was for the middel two diodes to the solenoid 2 and 3 wiring should have shown + from one diode and neg from the other in stead drew + and + to the diode which would not have created a circuit.

this system basically replaces a core unit for switched two terminal auto pilots,the only downside is it does not have a rudder sense/transducer,so could cause damage with big powerful units when they reach full lock,would reccomend fitting a breaker in case of overload on the battery side.

[44'cruisingcat]

Originally Posted by EvermanJ

ive been looking on ebay and the only rotary drives i can find are the raymarine, which is nice except i think they need the core pack to work which is an extra 2k. can you confirm wheather or not these drives rquire the core pack? id like just the drive unit and head.

Sorry, I was under the impression your head unit had failed, and assumed you still had a working corepack.

[atoll]

a picture is worth a 1000 words,the diodes i used were 8 amp,but don't need to be this powerful,as very little current needed to activate the solenoid.

the solenoids are similar to this one,rated at 150 amps.

in your case instead of solenoids you could use 4x 30 amp relays,cheaper,quiter and sufficient for a motor of up to 300watts.

pm me again if you have queries
brg atoll

[atoll]

Originally Posted by olaf hart

Great stuff, but I find it difficult to understand the second wiring diagram.
The leads from the control unit seem to go to the solenoids, but not the terminals.
The first one was easier in a schematic form, any chance of posting a modified schematic diagram?

hope this helps

[olaf hart]

Thanks for that

[henryk]

This is a great stuff. I just bought a new autopilot direct from the factory in England, Hy Pro Hydraulics. A self contain hydraulic unit with 675 kilo trust for much less than i would have to pay for Raymarine linear drive type 2. It was $1500 delivered to Grenada. A friend of mine built me a control unit similar to your diagram. We use standard automotive relays with the diodes.I have a smart. Until today i have a smart pilot x-5, a wheel unit that i hated so much that almost never used it. So we decided to connect the relay box to the existing course computer and using existing 6002 display. Everything was OK, but the thing wouldn't work. After spending many hours trying to figure out what's wrong, we found that there is only 6 volts going to the drive unit, but 12V coming in to the core pack. We checked the specks an it says 12 volt everywhere, in and out. Is it that the core pack is malfunctioning or it's sending only 6 volts to the original wheel drive Any feedback would be highly appreciated.
Henryk