Hydraulic rams - autopilot

TiggerToo

TiggerToo

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How do they work?

I mean: if you don't want to engage the autopilot, but hand steer, what happens to the ram?
What sort of things can go wrong?
 
Are you definitely thinking of hydraulic? They do exist, but electric drives are more common and sometimes mistaken for hydraulic.

The Raymarine electric drives have a clutch which is operated by an electromagnet. When 12v is applied to the clutch wires, it engages and locks the drive to the motor. When the voltage is removed (either because the pilot is set to standby or because the power fails) the clutch disengages and the leadscrew can spin freely, allowing the ram to be pushed in and out with very little resistance.

It is normal to attach the ram to its secondary tiller with a pin and R-clip rather than a bolt, so that it can be quickly removed if it somehow jams, but I don't think that's at all common.

Pete
 
I've defo got a hydraulic one; at least I think that's what the little container sitting above is for! Always assumed that some sort of bypass valve opened when disengaged, but this would mean steering getting irretrievably jammed if the thing ever failed to activate. Interested to hear the answer to this question.
 
dom said:
....this would mean steering getting irretrievably jammed if the thing ever failed to activate. Interested to hear the answer to this question.
Click to expand...

that's what I was wondering.

I have the feeling that anything which can go wrong probably will, at some point.
 
Tigger Too, that one is electro-hydraulic with integrated motor to feed the oil to the ram (one side or the other of the piston, depending on desired direction.

I'd like to hear about your need? An autopilot wants to steer the boat by some sort of management, controlling the motor driving the ram.

The common setup when the boat is alresdy equipped with hydraulic steering, is a control panel, a course computer, a compass (electronic) and an electric pump (to drive the existing ram).

The ram does not care if hydraulic oil is delivered from a helm pump turned by hand or the electric pump so integration is straightforward (given an electric pump that has valves, designed for the purpose).

Most pumps come from Octopus, regardsles of label on the tin.

For dimensioning parts you need to know the ram volume because the pump capacity should be large enough to make a full stroke within the number of seconds needed to steer you boat, typically 10-15 seconds for a 60 degree movement.

The course computer and control panel most often support NMEA communication and will talk to other equipment onboard - eg. chartplotter and sounder.
 
All steering rams used with an A/P regardless if they are all electric (Raymarine) ,electric-hydraulic or hydraulic with external pump must have a bypass method or you couldn't use manual steering.
They should be attd to the steering with a quick disconnect clip as mentioned by another post.
Non-release of the bypass is extremely rare but anything is possible-hence the quick disconnect clip.
If your boat already has hydraulic steering,adding an electric-hydraulic pumpset tee-d into existing steering lines & using existing ram is simplest/cheapest. If your boat has mechanical steering,the Raymarine M8113x electric ram is simplest/cheapest. IMHO

Good explanations of A/P operation have been posted,but I recommend you spend some time familiarizing yourself with small boat autopilots-how they work,how to install,how to setup & adjust & what to realistically expect from them.
In my 30+ yrs experience in the marine business, I found A/P's to be the most troublesome item of electronics on boats-mostly because of their "mechanical" nature,but also because they were poorly installed or matched to vessel,poorly adjusted-usually by a poorly educated owner. No offense intended - one cannot expect the avg. boater to be an expert on everything aboard.
The brand of electronics doesn't seem to matter-any good brand will steer your boat equally well & last many years.(Gasp!) IMHO.
It is usually the interface between the drive unit & the boat's steering that is the source of problems for reasons given above & because it is the wear & tear area.

Hope I haven't scared you-autopilots are one of the most useful kit to have aboard & you will wonder how you survived without it.
However,they are not as "plug-n-play" as most other electronics & a good study of them is warranted to get your $$ worth.
Google some owners/install manuals & read up. Don't get hung up in the bells & whistles-most of todays pilots will spew/rcv data to/from any other electronics. The important thing is to have an installation that will steer your boat satisfactorily. You can play with the fancy interfacing after you learn to set up & use the basics of the pilot to hold a course.

Cheers/ Len

Cheers/ Len
 
Len Ingalls said:
All steering rams used with an A/P regardless if they are all electric (Raymarine) ,electric-hydraulic or hydraulic with external pump must have a bypass method or you couldn't use manual steering.
They should be attd to the steering with a quick disconnect clip as mentioned by another post.
Non-release of the bypass is extremely rare but anything is possible-hence the quick disconnect clip.
Click to expand...

Aha, excellent post; I suspect Tigger Too and myself will be searching for ours this w/e :D
 
TiggerToo said:
How do they work?

I mean: if you don't want to engage the autopilot, but hand steer, what happens to the ram?
What sort of things can go wrong?
Click to expand...

Mine has a bypass valve which without any power applied allows normal steering to take place and is hence 'fail safe'. When I purchased the ram it came with a bypass valve that required power to be applied to allow normal steering. Investigation showed that this is common for long distance shorthanded boats where the current draw of the solenoid valve (clutch) needing to be constantly active is a significant drain on the boat electrics so they work the other way round. Hy-Pro make a significant number of units for many autopilot providers and are well worth contacting. Mine is driven by a Raymarine computer, control head etc.

Matching the boat, ram size, pump capacity and autopilot output is key to the setup.

Yoda
 
I fitted a hydraulic autopilot to a tiller steering system. The bypass is a manually operated valve at the helm. It has two advantages. One it won't go wronging can be disengaged without any electronic input and two it doesn't use any additional power to either operate the autpilot or disengage it. It's done quite few thousand miles now.
 
In an emergency you may need to remove the ram, so it makes sense to put a washer and R-pin onto the tiller or quadrant. Whipping the R-pin out means that the rose-joint can be unshipped from the pin and seized/disabled ram is removed from the steering.
 
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