Autopilot to Hydraulic Steering ?

[andreas.mehlin]

If à boat has hydraulic steering but lacks autopilot, What is the easiest way to go to add an autopilot? Now the drive sits on the transom (rudder on transom)

Wheel pilot? Or add something to the hydraulic system that exist today?

Inexpensive is nice

[kaimusailing]

I have a dual wheel hydraulic system, one is out on deck, the other is in the pilothouse. I put a wheel pilot type of autopilot on the one in the pilothouse so that the autopilot is out of the weather. I know many of the posters here have below deck hydraulic autopilots. Especially for the heavier boats. These are more expensive, but if you need high capacity it's a good way to go. Someday I will add a windvane pendulum servo, but I will have to dissengage the hydraulic to use it.

[Jesse]

An autopilot with a hydraulic pump incoporated in your steering system will be strong and reliable and usualy an easy installation.

[andreas.mehlin]

How much are we looking at if going to implement the autopilot to the hydraulic system? Boat weighs 12k lbs

[S/V Alchemy]

You want the 25 cubic inch Teleflex hydraulic ram or something similar. Basically, you combine a control head (I like ComNav's) and a second ram to accompany your original ram or pump, depending on your set up.

My boat is like Kaimusailing's, with an outside "sailing helm" and a "pilothouse helm" driving the same ram. This pushes a welded tab on a transom-hung rudder. When under wind vane, I bypass the hydraulics manually and the tiller does the steering as guided by the windvane.

If the engine's running, the AP is selected. Basically, it's two discrete ways to auto-steer, one needing amps and the other wind and string.

[boden36]

Our autopilot drives the wheel through a chain. (The hydraulic unit on the wheel has a shaft protruding from the rear which is keyed for a sprocket).
All hidden, and less complicated hydraulic circuitry.
Regards,
Richard.

[Jesse]

You will need a control head at each helm station, a heading sensor, a rudder position sensor, an autopilot processor(brain), and an electric/hydraulic pump. These things vary as greatly in price as they do in quality and we are fortunate to have some very good existing threads on this topic that are well worth exploring. Good luck with your project.

[44'cruisingcat]

Cheapest would be a wheel pilot, but it will probably need a rudder position sensor, because with hydraulics the straight ahead position of the wheel can change.

A hydraulic A/P would be better, (more powerful, quicker response) you'd simply plumb the autopilot hydraulic pump in parallel to the existing helm pump. (Assuming the helm pump has anti-feedback valves)

You don't need to add an extra hydraulic cylinder (or ram) if the existing steering works OK. Just the A/P pump, which will drive the existing cylinder. You do need to find the specs on the existing cylinder (ie, it's volume) though, so you can match the A/P pump to it properly.

[Redcoat]

I have a 416 which has two steering stations.The high pump is aft.I have a Cetrek 609 head with a type 1 reversing pump.All I did was tee the lines to the pump. I have wagner b1 steering pumps and when I turn one the other one doesn't turn. So when I apply the autopilot the fluid runs free in the lines which everway my control head tells it to go. I 'm sure there is a more complex answer than that but that is how mine works.

[forsailbyowner]

as for price I paid around $4k for my furuno navpilot and installed it myself. Biggest pain in install was making platforms for the pump and rudder position indicator. Otherwise just the usual wiring fastening routing issues. As stated before td off the existing hydraulics.

[osirissail]

For an existing hydraulic steering system you need a reversing hydraulic pump in parallel with the helm hydraulic pump; a rudder position sensor; a compass sensor; control head and an autopilot computer.

- - The size of the pump and computer is determined by the size boat and existing hydraulic system ram capacity in cc.

- - The installation is quite easy except that you will have to cut into the hydraulic lines from the helm wheel pump. All in all, it is not a difficult D-I-Y job.

- - Prices vary greatly with the reputation and reliability of the system you choose. I personally like and use the Robertson by Simrad with an AP-28 control head and a computer able to handle 10 amps 12VDC. It has worked reliably for over a decade even in some really nasty conditions.

- - You go to the Simrad Robertson website, pick out the components and then price them at various marine electronic outlets/stores.

Drive Unit | SIMRAD RPU160 | Marine Autopilots
Marine Autopilot Computer | SIMRAD AC series
Rudder Feedback Units | SIMRAD Autopilots
Heading Sensors | SIMRAD Autopilots
Marine Autopilot Control Units | SIMRAD AP series | Award Winning

[Jimbo485]

Is it possible to hook up your PC to the hydraulic pump via a parallel port and a transistor (or solid state relay), write a piece of software for the PC, use a puck GPS for direction and connect the rudder position sensor back to the PC as well. And thus do away with the A/P computer and head?

[44'cruisingcat]

You really need to be able to connect a heading sensor - fluxgate compass - too.

And you'd need a good power amplification circuit, as the A/P pump can draw decent current, and it needs 12 volts.

But if you're good enough with software it should be possible.

[osirissail]

Originally Posted by Jimbo485

Is it possible to hook up your PC to the hydraulic pump via a parallel port and a transistor (or solid state relay), write a piece of software for the PC, use a puck GPS for direction and connect the rudder position sensor back to the PC as well. And thus do away with the A/P computer and head?

Yes, there was a thread about that on CF awhile ago. Problem is the "computer" part of an autopilot has a lot more stuff in it than simply a "left/right" command to steering. Feedback loops, sea-state algorithm, and throw limiters, rate sensors and of course, compass input.

You could put all this into your PC but then you would most probably just built a very expensive and not very good autopilot computer compared to ones that have been designed and modified for years to output optimum performance. Or in other words, re-inventing the wheel the expensive way.

[matauwhi]

G'day, mate. Ditto on Osirissail's post. +1 on S/V Alchemy's ComNav recommendation, we have had nothing but success with their units during our time at sea. Depending upon the size of the hydraulic pump you purchase and the sea conditions, the pump can draw around 10 amps an hour, so you have to be mindful how you are going to power it. Have a great XMAS. Cheers.