Hydraulic steering

[douglas_family]

We had been looking at fitting an autohelm to our existing mechanical steering but there is limited space arround the top of the rudders (located in the back steps) and a local 'expert' said we might have trouble fitting the hydraulic rams in place.

The current cables are not great showing signs of corrosion and the steering is very stiff and the auto pilot system was going to be expensive.

So we've asked him to quote for changing over to hydraulic steering while integrating a new auto helm. He's being slow to get back to us as he is awaiting advice from Vetus about the pump set up for a catamaran. (prehaps not such an expert)

Does anyone have any idea how much this should cost for supply, is the Vetus system any good. I've come across Hydrive on the net and there blurb sounds convincing (could just be good marketing though) anyone have any experience of this?

Thanks

John

 

[michael_w]

I'd never have hydraulic steering. It is utterly lifeless with no feedback from the rudder. My chum owned a Catana 43. Lovely boat but difficult to get the best out of her owning to the hydraulic steering.

If you do fit it, a rudder angle indicator is useful.

 

[douglas_family]

The Hydrive claims to provide feedback to the helm! We haven't got much feedback now because the steering is so stiff and we ca't possibly do without an autohelm. So it may be the best solution for us.

 

[hightech]

Depending on the layout of your hulls around the rudder area, it should not be too difficult to install hydraulics. It may be that if space is short that you could fit two single ended rams, one on each rudder, and cross pipe them accordingly. Try to use sould piping for the majority of the pie runs and only go to flexi where there is movement required.
You will need substantial GRP or other pads building up for mounting the outboard end of the ram(s) and suitably mounted tiller bars of the correct length.

The autopilot pump is a minor addition to the system and can be put almost anywhere in the pipe runs, just make sure there are check valves in the helm pump (usually standard now).

 

[willie4646]

Hi John, I replaced my wire and pulley steering system on my Oceanic Catamaran last year with a hydraulic system, it felt strange to steer at first but you soon get used to it, it works great on autopilot. Should have done it years ago. As an engineer I was able to construct the system myself, using different manufacturers of the components so I can't advise on what's the best. I went for the Raymarine autopilot system because it was reasonably priced and seemed popular, the system consists of course computer, fluxgate compass, and rudder angle indicator, the latter being a must as the hydraulic system has helm creep making it difficult to ascertain rudder alignment when at the mooring.
Willie

 

[snowleopard]

The complexity of fitting hydraulic steering to a cat depends on one vital factor - do you have a mechanical link between the two tillers?. If you do then it's a simple matter to fit one ram to either one of the rudders or to the tie bar. If not, and you need to have a separate ram on each tiller it becomes a bit complex.

The problem is that if you fit two rams in series there will be a small amount of leakage past the pistons and the rudders will get out of sync. You have to have a mechanism to re-align the two rams fairly simply (it may need doing once a month or more so you don't want to be messing about with bleed nipples & bottles of oil). There is also the problem of how to bleed the middle section of pipe that joins the two rams.

The system we have is that the two pipes to each ram pass through a high-pressure connecting valve. When the steering is put hard over to one side, one ram will be at full extension and the other will not because it's got out of sync. When you force the wheel beyond the full-lock position, the extra pressure opens the connecting valve and allows oil to pass in or out of the middle pipe until both rams are at full extension.

And just to make it more complicated, this mechanism means that you have to use copper pipe rather than plastic (you use a short length of flexible pipe to connect the rams so they can move).

Get a professional to design the system for you!

 

[wotayottie]

I used a Vetus pump to replace the original teleflex (?) on my Prout. The pump was fine and worked well but gave no feedback at all because it was fitted with anti feedback valves as standard. As I understand it, these are needed for mobos who dont want feedback from heavily lopaded small rudders.

No feedback was both an advantage and a disadvantage. Made sailing hard on the wind difficult and not a lot of fun. On the other hand tacking was easy - turn the wheel and let go of it whilst the boat is going through the wind and you are operating the sheet winches. Once on course again, back to wheel, centre it and off you go.

On balance I would prefer a rod linkage system with feedback.

 

[Bodach na mara]

I fitted a Vetus system about 8 years ago because the existing cable system was very stiff. I agree that there is not much (but NOT no) feedback from the rudder, but there was absolutely none with the stiff cable system. The changeover cost about £600 (at a guess, I can't remember exactly) and I did the work myself. I have never regretted it. The steering is now finger light, where before you really had tu push hard on the wheel to move it, and it would stay there against any feedback hat the rudder could produce.

I have had only two niggles. It loses a little fluid from the ram and there is no "header tank" to provide a reserve of fluid. Also there seems to be one of the five driving cylinders in the pump that "takes a holiday" from time to time. This means that the wheel turns about 60 degrees without anything happening. It does not cause any problem when hand steering but the Autohelm does not like it! It is not as if you are on a road or anything. I say this because a friend that I discussed this with told me of his time in the Cadet Corps driving armoured personel carriers. They had hydraulic steering with the same problem and this made driving them in convoy down the A74 at 50 mph great fun. He says!

 

[wotayottie]

Certainly had neither the free play problem you descibe, nor the leakage issue to any degree. I used to have a very small leak between the two sides of the ram which meant that I could still very slowly turn the wheel when I got to full lock, but that was only an academic issue and only came about when I changed from normal hydraulic fluid to sae 10 fluid to lighten up the steering a bit.

There was a header tank in the pump itself. And I agree with you there was a tiny bit of feel to the helm but as you describe you could turn the wheel onto full lock and leave it there with the boat motoring round in circles if you were so minded. It was a useful facility when single handed.

 

[colinmi]

Hi John

I replaced the wire and pulley system, in my Grand Banks, with a full Vetus system last year. Main reason I changed was the wires were fitted to an old auto pilot which was no longer working and I wanted to have the full functionality of a modern auto pilot.

We have two manual steering pumps..one at each steering position and a 12volt pump that is driven by the auto pilot. The auto pilot indicates both rudder position and course deviation. There are also a couple of manual valves which "short out" the hydraulic circuit and allow a manual tiller to be used, at the rear of the boat, in the event of some sort of system failure. Likely schmatics for suitable systems are well detailed on the Vetus site, as are costs.

Our system is installed with nylon tubing and simple compression type fittings. Installation is straight forard for anyone with decent DIY skills.

The system works well, both under auto pilot and when steering manually. Our system does indeed have a header tank, also supplied by vetus.

I have to say it was a pig of a job to bleed it properly, but apart from that, quite happy with everything.

Merry Christmas

Colin