Copper tubing steering system replacement

[Skip Sunnell]

For various reasons over the years (1979 vintage CHB trawler) the copper tubing has been "patched" in my hydraulic steering system. There has been a plethora of leaks which have required a constant monitoring of the oil level in the upper helm hydraulic pump. When oil in the system gets low, the upper helm ceases to respond. Because of the numerous fittings in the system I'm considering replacing all copper with flexible hydraulic hoses to eliminate fittings that have been tightened so many times I am concerned about their integrity. Vibration, I assume, is the culprit that is causing the problems, and it seems to me, looking at the overall problem, that running new copper tubing might really be a very difficult thing to do.

 

[SoWhat]

It depends. If you have a straight shot from the bridge to the ER, then it might be doable. If they drilled 5/16 holes for 5/16 tubing, then it will be a project to run 3/8 hyd lines. Access is usually very tight.

I replaced all my cu fuel lines with hose. Very satisfied with outcome. (and no leaks)

 

[Lepke]

My hydraulic steering is from the early 1970s and 3/4 copper pipe. My plan is to replace it with hose. I don't see a problem. Probably the cheapest hose is buying a roll on ebay. You can get field fittings that go together with a couple wrenches.

 

[O C Diver]

I'm doing it now. Not replacing copper but up grading hose size. My Hynautic helm specs 1/2" up to 40' and 5/8" beyond. The village idiots that built my boat plumbed it in 3/8". Found some 1/2" thermoplastic hydraulic line and stainless steel jic fittings on line for around $350 for 40' lengths. Helm pump and cylinder will be back from overhaul tomorrow. Add $120 worth of fittings to clean up the plumbing and $85 for 2 gallons of aircraft hydraulic oil. All told, the rebuild should be $1,100. Steering effort should be about half of what it was.

Might want to think about rebuilding your helm pump and cylinder while undertaking the lines project. If they haven't been done, 40+ years equals living on borrowed time.

Ted

 

[Xsbank]

Make sure your hydraulic oils are compatible with the seals you used in the rebuild? “Aircraft hyd oil” (mil 5606?) has specific requirements for aircraft, not boats.

Pictures would be very nice...?

 

[Mako]

I understand there's a huge convenience factor for replacing with rubber hose, but it seem to me that copper tubing, especially if up-sized an extra 1/8", would present less frictional losses. That would allow moving the attachment point on the rudder arm, and thus reducing your turns lock-to-lock by a certain amount.



Or is this rather insignificant in most person's minds?

 

[rslifkin]

I understand there's a huge convenience factor for replacing with rubber hose, but it seem to me that copper tubing, especially if up-sized an extra 1/8", would present less frictional losses. That would allow moving the attachment point on the rudder arm, and thus reducing your turns lock-to-lock by a certain amount.



Or is this rather insignificant in most person's minds?

It probably varies depending on the boat. Some could do with less friction in the steering or faster steering, others are already pretty good.

 

[O C Diver]

I understand there's a huge convenience factor for replacing with rubber hose, but it seem to me that copper tubing, especially if up-sized an extra 1/8", would present less frictional losses. That would allow moving the attachment point on the rudder arm, and thus reducing your turns lock-to-lock by a certain amount.



Or is this rather insignificant in most person's minds?

From a sizing standpoint, copper tubing is measured OD (outside diameter) where as hydraulic hose is measured ID (inside diameter). Depending on wall thickness, 5/8" copper has an ID of close to 1/2". The hose fittings tube is a little smaller for maybe 2".

As a side note, Hynautic doesn't recommend going to 3/4" (my original plan) as it's just about impossible to purge the line of small bubbles with a manual helm. Moving the bubbles requires some velocity. The larger the tube size, the more likely it is for the fluid to go around the bubble.

Ted

 

[O C Diver]

Make sure your hydraulic oils are compatible with the seals you used in the rebuild? “Aircraft hyd oil” (mil 5606?) has specific requirements for aircraft, not boats.

Pictures would be very nice...?

That's what the factory authorized rebuilder recommended and what has been in the system for 18 years.

If you have seen any of my refit threads, you should know I become obsessed. There will be a thread, with pictures, and more information than any sane person would want to know.

Ted

 

[Xsbank]

Bring it on, OC! We can take it.

 

[boomerang]

I replaced the 3/8" copper lines in our boat with 3/8" seastar nylon tubing. I used the same seastar hydraulic fluid to refill the lines and the only plumbing changes I made were the tee junction where the lower helm and the bridge join was moved aft about 10 feet and an autopilot pump. Prior to changing the tubing, the system was super smooth. So smooth that I could spin the larger diameter lower helm wheel and it would continue to spin on it's own like a flywheel. Now ,with the nylon tubing, the system acts like a typical hydraulic steering steering setup. The wheel at either helm readily turns the rudder port or starboard but you have to grind away at the helm with a lot more effort than with the copper tubing lines. Could it be the addition of the pilot pump or the relocation of the upper/lower helm junction causing the helm to be stiffer? Possibly but I'm really thinking it's got to do with the internal friction of the different tubing.
Just my thoughts on the subject.

 

[psneeld]

Boom.. could the inside diameters be even a tad different?

Cant imagine the cause is internal friction copper versus plastic..

Or maybe as you mentioned...the other changes in the system.

 

[ghost]

Sounds like a restriction, could well be the ID. I replaced my copper return line (the only one that was low enough to get wet and corrode) with nickel copper tubing. Only downside is cost, but as a project overall not terribly material. The real cost is the time to cut enough access panels to do it. Nicke copper won’t corrode, at least in my lifetime. They typically don’t like hose for long runs as it is not as rigid, you don’t want your hydraulic lines acting like rubber bands. I’m sure the nylon works well for rigidity.

 

[Nomad Willy]

I understand there's a huge convenience factor for replacing with rubber hose, but it seem to me that copper tubing, especially if up-sized an extra 1/8", would present less frictional losses. That would allow moving the attachment point on the rudder arm, and thus reducing your turns lock-to-lock by a certain amount.



Or is this rather insignificant in most person's minds?

I had those thoughts when I first bought Willy .. 30’ Willard. It had the push-pull single cable steering that I had in my first trawler .. 25’ Albin. The Willard had 5.5 turns L to Lock. It was dreadfully slow and somewhat loose.

So I installed a hydraulic system.
But I was into the notion that larger fluid lines would lower friction and insure light steering .. and I liked light steering. So I spec’ed a Capilano pump and appropriate slave cylinder. Most 40’ boats probably have the same size units. Then I choose much larger orange hydraulic fluid hose that was typical hose on backhoes and much other small heavy duty hydraulically controlled equipment. Huge compared to the typical shinny black hose usually used.

Some of my anticipated light steering got scuttled by installing the end of the cylinder rod to the hole on the rudder horn closest to the rudder shaft. That gave me the 3 turns L to L that I wanted.

But I didn’t experience the light steering I was anticipating.
I think most of the heaviness that prevailed was due to the fast steering and decreased mechanical advantage. But I suspect most of the stiffness was/is due to the hydraulic seal friction. And in order to “fix” it would require new and smaller hydraulic cylinders.
We had the boat in Alaska by then and after many many hours at the helm I’ve come to fully accept my imperfect steering. And I love the way it stays on the course last set faithfully. In calm seas I can (w a bit of very slight movements) back and forth to let it stay fixed for 2 or more minutes at a time. This and having a 1st mate meant I didn’t really miss the auto-pilot that blessed the Albin.

But the friction is in the seals .. l think.

 

[boomerang]

Boom.. could the inside diameters be even a tad different?

Cant imagine the cause is internal friction copper versus plastic..

Or maybe as you mentioned...the other changes in the system.

You got me thinking. The SeaStar nylon tube is labeled 3/8 but that must be the OD. The nylon tubing wall thickness is most certainly thicker than copper tubing so it stands to reason the nylon ID is less than the copper I removed. Again, it isn't a huge deal because the benefits of the nylon outweigh the benefits of the copper tube in my case but that sure is something the OP needs to take into consideration when replacing the steering lines.

 

[Mako]

Some of my anticipated light steering got scuttled by installing the end of the cylinder rod to the hole on the rudder horn closest to the rudder shaft. That gave me the 3 turns L to L that I wanted.

Eric, it would be an interesting experiment if you tried using the previous attachment point in the rudder arm. Go back to, say, 5 turns lock to lock. And then you can judge if it is resistance or just the added pressure of 3 turns.

 

[Keysdisease]

One thing that's different between the smaller boats plastic tubing systems and the larger boats copper tube systems is how the tubing will expand under pressure.
Under the kinds of pressure these hand operated systems make, there's not a lot of pressure, but copper doesn't budge at those pressures and plastic will swell even if just a very small amount. When you add up the full length of tubing and have it swell just a tiny bit, it adds up, and results in a "mushy" feel at the helm.
If you check the specs of plastic tubing systems they will see that if the total run is more than XX ft copper should be used.

That's why

 

[O C Diver]

One thing that's different between the smaller boats plastic tubing systems and the larger boats copper tube systems is how the tubing will expand under pressure.
Under the kinds of pressure these hand operated systems make, there's not a lot of pressure, but copper doesn't budge at those pressures and plastic will swell even if just a very small amount. When you add up the full length of tubing and have it swell just a tiny bit, it adds up, and results in a "mushy" feel at the helm.
If you check the specs of plastic tubing systems they will see that if the total run is more than XX ft copper should be used.

That's why

That depends on the system. Some systems use thermoplastic hydraulic line. The system pressure is maybe up to 500 psi where the line operating pressures are in the thousands of psi.

Ted

 

[Nomad Willy]

Eric, it would be an interesting experiment if you tried using the previous attachment point in the rudder arm. Go back to, say, 5 turns lock to lock. And then you can judge if it is resistance or just the added pressure of 3 turns.

Mako,
Even if it did lower the steering effort I would .. no way consider going back to 5 or 6-1 steering. It’s not that hard ... just an observation that it was/is higher or more resistance w the new system. 6-1 would be fine most of the time but when it comes time for close maneuvering 6-1 is unthinkable.
I did think and hope it would be one fingertip control like a 55 Buick but I turn lock to lock w one finger at 3-1 as it is. Just a little hard on the finger at times. Never go away w any sensation of my finger hurting.
However I’m sure the friction is from the oil seals.

 

[Mako]

After all these years helming various boats with L-to-L from 2 turns to over a dozen, I have to conclude the same as you.

I think 3 turns is ideal and would prefer not to exceed 5. Tough to do with manual hydraulic however on 50’+ boats unless the wheel is 3 ft in diameter or more, for leverage.

 

[sean9c]

You can't really generalize about plastic tubing. Some of the tubing sold for marine steering systems is just unreinforced nylon, so it's likely to expand some under pressure. Thermoplastic hydraulic tubing comes in a bunch of different flavors, all with reinforcement mesh in the construction, but some have fiber mesh, some have steel mesh, some have both, so they're all going to react to pressure differently. It all depends on the application and what you're looking for. One of the reasons thermoplastic tubing is used is that it is more flexible than hydraulic hose. You can probably make an assumption that the more flexible it is the less reinforcing it has and because of that might move more under pressure. If it was me I'd look for tubing that had the largest bend radius that would work for my application, thinking that the more rigid the more reinforcement. I'd also think about if I wanted my tube to have steel mesh in it. While the mesh is incapsulated in the construction it is steel and it is around salt water.
Seems to me the logic system would be use rigid metal tube where you can and thermoplastic tubing where you have to.

 

[syjos]

I replaced the 1/2" copper tubing on Sandpiper with 5/8" copper refrigeration tubing right after purchase in 2000. I was replacing the Benmar autopilot with a Robertson/Simrad AP and an Accu Steer variable displacement pump. The larger capacity pump required the 5/8" upgrade. The boat has one Capilano variable displacement helm pump and two rams on one rudder.

I removed all the straps securing the tubing to the stringer and in the wire chase going up to the pilothouse helm. Flared the end of the new tube, connected it to the end of the old tube and slowly pulled the new tube through the boat. One person pulled and another slowly unrolled the tubing from the coil. Most of the run was straight except for the 90° bend at the bottom of the chase going up to the pilothouse. I used a copper tubing spring bender and slowly bent, pulled and straightened the tubing around the 90° bend without kinking the tubing.

I was able to install a continuous length of tubing from the helm in the pilothouse to the hydraulic pump located near the rear of the engine room and from there to the rudder. All the connections are flared. Only hoses are at the ram.

Took two people about 6 hours.

 

[O C Diver]

You can't really generalize about plastic tubing. Some of the tubing sold for marine steering systems is just unreinforced nylon, so it's likely to expand some under pressure. Thermoplastic hydraulic tubing comes in a bunch of different flavors, all with reinforcement mesh in the construction, but some have fiber mesh, some have steel mesh, some have both, so they're all going to react to pressure differently. It all depends on the application and what you're looking for. One of the reasons thermoplastic tubing is used is that it is more flexible than hydraulic hose. You can probably make an assumption that the more flexible it is the less reinforcing it has and because of that might move more under pressure. If it was me I'd look for tubing that had the largest bend radius that would work for my application, thinking that the more rigid the more reinforcement. I'd also think about if I wanted my tube to have steel mesh in it. While the mesh is incapsulated in the construction it is steel and it is around salt water.
Seems to me the logic system would be use rigid metal tube where you can and thermoplastic tubing where you have to.

While looking for the largest bend radius to indicate expansion potential seems logical, there are far to many variables in hydraulic hose to make that realistic. As a simple example, consider the outer cover. All the pressure retention is in the woven braids under the cover. A thick hard rubber cover will have much more bend resistance than a simple urethane cover. The rudder thickness could be chosen for abrasion resistance. Hose are also made differently with different bend radii to prevent the tube core from kinking.

Having flexed several different hoses in my search for a replacement, you can find 2 different hoses that seemed identical, but one had more than twice the working pressure of the other. Really doubt the 2 hoses would have similar expansion characteristics with radically different operating pressures.

Ted

 

[sean9c]

I suspect that you're correct and looking at tube with higher operating pressure is also a good idea. I've also found that you can buy thermoplastic tube with steel braid as well as fiber, also with both fiber and steel, so lots of options.
More research is needed, alway fun.

While looking for the largest bend radius to indicate expansion potential seems logical, there are far to many variables in hydraulic hose to make that realistic. As a simple example, consider the outer cover. All the pressure retention is in the woven braids under the cover. A thick hard rubber cover will have much more bend resistance than a simple urethane cover. The rudder thickness could be chosen for abrasion resistance. Hose are also made differently with different bend radii to prevent the tube core from kinking.

Having flexed several different hoses in my search for a replacement, you can find 2 different hoses that seemed identical, but one had more than twice the working pressure of the other. Really doubt the 2 hoses would have similar expansion characteristics with radically different operating pressures.

Ted

 

[Ron Stevenson]

Thank you for posting, I hope to replace tubing sometime in the future, in my37' '79 North Sea Trawler (CHB hull). In the mean time, my Wagner ram had been leaking. Wagner originally in Vancouver BC, sold out. I finally found Florida Rigging & Hydraulics 561 863-7444 to be very helpful to get a rebuild kit. $70. After receiving it, and working in our Yacht club workshop, one of our members (retired from boat repair, who commissioned these boats in the 70-80's) was rebuilding his Wagner ram. He used Orings from the local hardware specialty store (free, too small of $ to write up) and seals from the local hydraulic repair/rebuilder- less than $8. That, a I confirmed with him that the hydraulic fluid mentioned elsewhere on TF at $16 a gallon at the big box home improvement store in the lawnmower section is the same. The old fluid was BLACK in the ram. i was surprised at the corrosion and grains of something in there. I honed it, new seals, followed Wagner PDF bleeding procedure that I found on TF, and went cruising for three weeks! I had to loosen hoses at the ram to gradually work out the air, one hose, then the other. Wait 24 hours, do it again. Thank you Trawler Forum!

 

[ben2go]

For various reasons over the years (1979 vintage CHB trawler) the copper tubing has been "patched" in my hydraulic steering system. There has been a plethora of leaks which have required a constant monitoring of the oil level in the upper helm hydraulic pump. When oil in the system gets low, the upper helm ceases to respond. Because of the numerous fittings in the system I'm considering replacing all copper with flexible hydraulic hoses to eliminate fittings that have been tightened so many times I am concerned about their integrity. Vibration, I assume, is the culprit that is causing the problems, and it seems to me, looking at the overall problem, that running new copper tubing might really be a very difficult thing to do.

If your system doesn't have power steering and is a low pressure system, use nylon. If it is a high pressure power steering system, use re-enforced hydraulic hose. A heavy equipment center can get the hose cheaper than a marine supply house. You just need to know the hose spec and fittings for your system.

 

[mvweebles]

Like Eric on nomad willy, I replaced cable steering on my Willard 30, but that was 25 years ago. I used hynautics high pressure nylon hose and fittings. Worked fine but would be expensive these days.

I am redoing steering on my Willard 36. I have a bunch of nylon hose I found at a bargain store, but if I were to go from scratch, I'd do double flare copper. Cheaper and works fine. Can be fixed anywhere on the planet

 

[AdkChris]

I replaced my copper return line (the only one that was low enough to get wet and corrode) with nickel copper tubing.

Having replaced a lot of transmission cooling lines with copper or steel lines back in the day. I can say Copper-Nickel is a dream to work with. At least as flexible as soft copper. I have yet to manage to kink this stuff and I was a lot less careful than I used to be with with copper or steel lines. First place I looked was $37 for 25'

https://www.amazon.com/Copper-Nicke...ocphy=9003589&hvtargid=pla-455725438014&psc=1

 

[sean9c]

Before you pick a tubing material you might want to do some research on your specific system and understand its pressure. Kobelt says my manual pump system can generate 1000# psi of system pressure. Hate to find out the hard way you've chosen the wrong material.

 

[Lepke]

Plastic tubing can crack in really cold weather and if run near heat sources, can soften and reduce bursting pressure.