Hydraulic Steering - Cupro Nickel

[tayana55]

Usually copper refrigeration pipe is used, however cupro nickel appears to be stronger and does not corrode in a salt water environment.
Anybody had any experience with cupro nickel pipe for hydraulic steering?

[tayana55]

Originally Posted by tayana55

Usually copper refrigeration pipe is used, however cupro nickel appears to be stronger and does not corrode in a salt water environment.
Anybody had any experience with cupro nickel pipe for hydraulic steering?

I see no interest at the moment, cupro nickel is and has been used widely in the automotive industry for brake pipes. It is subject to winter road salting and gritting in colder countries and is highly resistant to corrosion.

Here's a link for future interest.
Cupro Nickle Tubes - Cupro Nickel Tubes and Heat Exchangers Cupro Nickel Tubes

[mikereed100]

I looked at this when putting together my hydraulic system and ended up using nylon tubing. The burst strength, if I recall, is 2200 psi vs 800 psi for copper. Also, much easier to install, especially long runs with bends.

[tayana55]

Originally Posted by mikereed100

I looked at this when putting together my hydraulic system and ended up using nylon tubing. The burst strength, if I recall, is 2200 psi vs 800 psi for copper. Also, much easier to install, especially long runs with bends.

I thought 800 psi was working pressure for 1/2" copper, cupro nickel has higher working pressure for the same size tube.
What size nylon did you use and what was the run length ?
From helm to cylinder on my boat is around 30 feet including bends, which brand of tube did you use and what does it perform like under heavy weather ?

[twistedtree]

I though the reason for using rigid piping rather than nylon or other types of hoses was to keep the steering from being spongy. All these materials bulge under pressure, i.e. when you are steering, but rigid piping bulges much less than hoses. We aren't talking about a lot of bulging, but when you have many 10s of feet it starts to add up. That's my understanding of why hoses aren't used throughout even though it would be much easier and probably cheaper.

[tayana55]

Originally Posted by twistedtree

I though the reason for using rigid piping rather than nylon or other types of hoses was to keep the steering from being spongy. All these materials bulge under pressure, i.e. when you are steering, but rigid piping bulges much less than hoses. We aren't talking about a lot of bulging, but when you have many 10s of feet it starts to add up. That's my understanding of why hoses aren't used throughout even though it would be much easier and probably cheaper.

That's correct and the reason I'm looking at Cupro Nickel.
There's also the problem that nylon and rubber hoses bulge more in warmer climates because they are more pliable at higher temperatures. Another issue is that if you are using an autopilot it has to compensate / over compensate to a spongy system, less precise steering and wasteful of energy making unnecessary adjustments.
I suppose it depends on the boat and the type of sailing, if you're just sailing the coast, or if you have short hydraulic runs, the specs are less demanding.

[mikereed100]

Originally Posted by tayana55

I thought 800 psi was working pressure for 1/2" copper, cupro nickel has higher working pressure for the same size tube.
What size nylon did you use and what was the run length ?
From helm to cylinder on my boat is around 30 feet including bends, which brand of tube did you use and what does it perform like under heavy weather ?

I used 3/8" tubing from Parker Hannifin. I believe the total run on my boat is close to 90' (catamaran with hydraulic tie-bar and autopilot). If I recall, the manufacturer of my system, Ultraflex, recommended nylon for runs of up to 100'. If there is any squish in the helm it is not noticeable. We have run in force 9 conditions under autopilot with no issues. I imagine any softness in the helm due to the tubing expanding under pressure is more theoretical than practical. Most of the time the tubing is not seeing anywhere near the pressures for which it is rated.

Nylon tubing has several important advantages. It is cheap and light enough that I carry an extra 50' roll in case of emergency. It is very easy to work with and does not require tubing benders and flaring tools. Installation is very easy, even if you have lots of sharp bends as I did. I installed ours in an afternoon. I inspect it regularly and have found no signs of chafe or wear, but if a section did chafe through I could repair it in minutes with fittings that I got at the local hardware store.

[tayana55]

Originally Posted by mikereed100

I used 3/8" tubing from Parker Hannifin. I believe the longest run is over 40'. If there is any squish in the helm it is not noticeable. We have run in force 9 conditions under autopilot with no issues. I imagine any softness in the helm due to the tubing expanding under pressure is more theoretical than practical. Most of the time the tubing is not seeing anywhere near the pressures for which it is rated.

Thanks for the feedback, its very useful to me. I'll investigate further, rigid tubing is a nightmare to install, especially in the larger sizes.