Hydraulic Steering Questions

[Matt sachs]

I'm to the point I need to install the helm pumps and lines for my steering system. The problem is I really dont know anything about this. Im looking for a good read on the topic and any advice you might have. I have a 50 ft full keel steel Roberts. There will be a helm in the wheel house and the cockpit and I want an auto pilot.
I dont want to build the system and find out later I didnt use the best of everything. Any good books come to mind? Or maybe a manufacturer that offers this type advice.

[forsailbyowner]

Teleflex Technical Reference Manual: Table of Contents

[Matt sachs]

Thanks, Ill take a look.

[xymotic]

I can't really help much but the manufacturer of my steering ram is Wagner and I can't imagine a stouter or more reliable unit

My system "seemed" really complex it has a wheel and a tiller and autopilot

But in reality it is just a closed loop of normal copper pipe like you would find in any plumbing install and a Y valve to disconnect the tiller for manual use

I intend to redo it with tubing & better fittings but the setup is simply a loop - in and out - easy!

[Andrew Troup]

Whatever you do, don't go for more than the minimum recommended mechanical advantage for the manual steering.

IOW: don't fit a bigger diameter cylinder (or go for one of longer stroke on a longer tiller arm) to 'make things easier' for the mechanicals, OR for the helmperson.

And it doesn't work to 'compensate' by fitting a small diameter wheel ... (although it's fine when motoring)

I've sailed on several boats with this misguided approach, and in one case it made the boat so difficult to steer we almost had to abort making a tricky landfall with offshore dangers in bad weather, which would have been straightforward with 'normal' steering.

Which would have meant adding several days to beat back to the island once the weather moderated, in the Southern Ocean against a strong west wind drift.

It's nightmarish trying to steer an undergeared big boat under sail, and you won't get tactile feedback, even from a system which in theory would provide it.

If you hate hand-steering with a passion at the best of times, I suppose it might be acceptable.

[Matt sachs]

Ah-ha. I guess I need to find out what mechanical advantage I need....a starting point. Thanks!

[Andrew Troup]

Originally Posted by Matt sachs

Ah-ha. I guess I need to find out what mechanical advantage I need....a starting point. Thanks!

If you want to enjoy hand steering under sail, I would recommend fitting a wheel the same diameter and the same mechanical advantage as would be recommended for a racer-cruiser of similar displacement using cable steering.

If you're concerned about the risk of heavy steering -- especially for people who are not powerfully built -- this can largely be addressed by fitting check valves (which will prevent them having to exert force to hold the wheel in a fixed position), but make sure that these can be taken out of circuit, by bypassing them with a "feedback" valve, and make sure this (and ALL the hoses and elbows) are the largest and shortest and contain the minimum number of tight turns* you can reasonably fit, to cut down fluid friction.

You may also want to fit a bypass from one side of the cylinder to the other AT the cylinder, for use with an autopilot or windvane steerer. This is often actuated by a solenoid valve, but make SURE you can manually override it if (some would say when) the marine atmosphere causes the solenoid coil to swell up and jam on the armature.

If not, you'll need some quick-disconnect to physically uncouple the cylinder.

One other thing to consider for sailing: a rudder angle indicator, easily seen, ideally without shifting your head. The position of the 'king spoke' is always a movable feast for hydraulic steering.

* avoid 'compact' elbows, in favour of 'swept bends'

[Matt sachs]

2 more questions, how many turns lock to lock at the helm? And how many degrees should the rudder rotate? Im looking at a ballanced piston with 11 inches of travel. This will give me 150 degrees of rotation if I go with a 5.5 inch arm on the rudder post. Is this a reasonale starting point?

[Fiveslide]

Good thread. Having simply used hydraulic steering and never worked on it, I will keep up and learn what I can.

150 degrees of rotation? Meaning 75 to port and 75 to starboard?

That seems like a lot to me.

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[Matt sachs]

Just found an article that said 45 degrees port and starboard is all I need. Wow, thats a long way from 150. This would simplify every thing because it will reduce stress on the mechanicals due to better angles.

So this is what I have so far.
2 helms 4.5 turns lock to lock.
1/2 inch copper tubing with no elbows, just sweeps.
12 volt Auto pilot
2 inch balanced cylinder with 11 inches of travel
max travel +/-45 degrees from center
Angle indicators at each helm

But now I have another question. Do you like feed back or no?

[Matt sachs]

I am going to use 1/2 inch copper K tubing. The working pressure is 1,534psi , burst 9,000+.

[msponer]

Hi,
We have a dual helm hydraulic system on a 48' boat.

I am having a second autopilot plumbed in at the moment, and the hydraulic folks here have suggested adding a hydraulic fluid reservoir that's visible from the pilothouse helm. So that if there's a leak we can see the level going down, and hopefully fix it before we unexpectedly lose steering.

They also recommended a pressure relief valve, to protect the fittings and seals on the cylinder in case the rudder hits something hard and gets back driven. In our case I passed since it's ~$600 and we have an oddly designed rudder that's well protected. But it might be something to consider for a less protected rudder. Though I imagine you don't need this for the kind of system Andrew is talking about.

You can have a valve that makes bleeding air out of the system very easy. Just open the valve and turn the wheels one way.

We have Capilano helm pumps, that allow you to adjust how many turns it takes to go from lock to lock. In practice we keep it at the lowest setting.

Our Raymarine autopilot control head has a rudder angle display in it. It is hard to drive without knowing where the rudder is.

Not having tactile feedback from the rudder takes getting used to, since it's now visual with the rudder angle, but as an aside, I also like how the rudder just stays where I put it. So I can just walk away from the helm to grind a winch or even go get a drink, and the boat stays on course. With my previous mechanical steered boat I always had to engage the autopilot or lock the wheel if I let go. A small difference, but at least it's not all negative to lose feel from the helm.

I am now wondering what kind of spares we need to bring for the system. To work around a leaking pump while mid-ocean, or whatever else can go wrong. I am bringing lots of fluid and caps to be able to cap off any section. Is there anything else? Copper tube with the flare tool and nuts?

Matt

[Andrew Troup]

Matt (msponer)

As well as taking a flaring tool and some fittings (ideally at least one of each fitting used, complete, not just the nuts) it would be a good idea also to have at least one pair of in-line unions, either with a flare both ends or better still a ferrule (olive) type not requiring flaring (eg Swagelok style), enabling you to cut out a damaged section of tubing part way along a long run (chafed or cracked) and splice in a replacement.

ON EDIT:

With several helm stations you effectively have spare pumps aboard, and could switch them to put the good one where you want it. I don't see any need to take a spare cylinder, but would take a complete set of spare seals for it.

and Matt (OP):

2 turns hard-over to hard-over would be more than plenty with a decent diameter wheel; with 4.5 turns it will be like steering a battleship, and you can forget about any possibility of feedback or feel, regardless of how you set up the hydraulics (eg with a feedback valve)

What type of rudder do you have: is there any area ahead of the pivot?

ON EDIT:
As Matt says, losing feedback does have a considerable benefit, but remember you can have your cake and eat it, if you design the system right, and include a valve so you can revert to a self-holding helm whenever you wish.

You may adjust to steering by brainpower rather than feel, but you might want to consider the situation of taking skilled crew with you and finding they cannot handle the boat in demanding conditions.

I was once on a trip where, broad reaching in a lusty gale, only one person of the six onboard could keep within 15 degrees of the course required to avoid getting blown past our destination. Unfortunately that person (who was not the owner/skipper!) was also the navigator, and there were a couple of tricky navigation problems involved in how to shape that course, past an unseen danger.

[Fiveslide]

Keeping the same travel in the hydraulic ram and number of revolutions of the wheel you're going to extend your tiller length to roughly 8" to reduce the total degrees of rotation to 90+-?

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[Matt sachs]

Thanks to everybody! This is just what I needed. Lots of good stuff here.