Recommendations for new steering lines for Hynautic Steering System

[albinalaska]

Good day,

I am wondering what opinions are out there regarding replacing our 40+ year old 3/8" copper hydraulic line. There are numerous posts on this forum regarding this subject so it's not my intention to oversaturate with duplicate posting, but I've rummaged through here and have not come up with the desired info.

Reading the manual for our Hynautic Steering System outlines that copper tubing with .032" wall thickness may be used or high-pressure soft hose equivalent to Aeroquip 2651 or SAE100R with 1000psi working pressure may be used as well.

STAINLESS:
grainger offers 50' runs of 3/8" stainless coils with .0319 nominal thickness for around $260 out of Seattle. Benefits would be the corrosive resistant properties of the 304 or 316. Psi shows about 2500 max which is well beyond what we would need but also the stainless would look really clean, which if you've seen any of my previous work on our refit, is important to us.

COPPER:
grainger also offers copper in 60' runs for around $170 but the max psi is around 700-900 on anything I've been able to find. The current system is copper and, as mentioned earlier is 40+ years old so if it's held until now, perhaps 700-900psi is acceptable. But I'm not confident in that for sure.

HIGH-PRESSURE HOSE:
I don't have an option for this route because I've heard numerous stories about issues with stiff steering or other issues related to the expansion of the hose under pressure. My general understanding is that hose is great for the short runs, like on smaller vessels for example, but anything for a 40' dual helm vessel should be rigid. Though I have also read numerous posts on this very forum where hose was used on vessels in the same size-class as ours without apparent issues.


The price differences are marginal enough, comparatively, that we want to go with the better option. Any insight or assistance would be very helpful! Part of me wonders if we can accomplish the same thing with $50 stainless or $40 copper from amazon, and perhaps my lack of experience in replacing this system is causing me to overthink what might be a simpler process.

Any feedback welcome!



Kyle

 

[ConejoBlu]

If it were my boat I would not use the copper. I would suggest using the stainless steel for the long runs and then transition to the flex at the connection point to the system components that have difficult access or need to be easily removed to service other parts of your boat.

 

[Duvie]

McMaster car has 60 and 100 foot coils of .035 wall copper tube rated at 1000 psi. I would go copper. Your current set up has lasted 40 years and stainless has issues with stress and corrosion in certain conditions. Plus I imagine the copper is easier to handle. On my current boat, I used Parker hose for ease of installation. I have had no issue with it but my vessel is single station and 27 foot.

 

[Keysdisease]

McMaster car has 60 and 100 foot coils of .035 wall copper tube rated at 1000 psi. I would go copper. Your current set up has lasted 40 years

What Duvie says, or copper tubing with .032" wall thickness per manufacturer

 

[O C Diver]

In 2021 I rebuilt the helm pump, steer cylinder, and replaced the lines on my Hynautic system. In my situation, the helm pump and cylinder were the larger size and installed with substandard size lines, which made the system much harder to steer. After consulting with a factory authorized rebuilder, I increased the line size. I'm not suggesting you increase your line size. However, finding hydraulic lines without steel wire in them was quite easy. They're a poly tube with a fabric strength braid (like Kevlar) and an outer cover. The fittings were swaged on at the vendor. I chose stainless steel, but brass and steel were available. I also found online brass fittings to use with the 37 degree JIC fittings.

As I bought the lines on line and changed the routing of the lines, it was important to get the length correct as the fittings would be attached at the vendor. I chose to use a 50' extension cord, but a 1/2" braided nylon line would work just as well. Obviously, just mark the length and measure with a tape measure.

For me, I didn't want any splices, didn't want to fight working tubing around bends, and wanted the easy flexibility that my previous lines had.

Everything worked out perfectly, made the helm easier to steer, and likely will be the last set for the life of the boat.

Ted

 

[Fish53]

I’ve used copper with my Capilano for forty plus years without any problems.

 

[albinalaska]

very helpful information! thank you for the input and suggestions! really appreciate the insight!

 

[Portage_Bay]

I rebuilt the Hynautic steering on my previous boat. Both helm pumps, ram, autopilot pump and all new lines. I chose high pressure two wire hydraulic hoses for the high pressure side. The decision to use hose was because of the difficulty of running hard lines and securing them. Copper needed to be secured to keep it from vibrating and work hardening. That and multiple 90 degree bends during installation would have started the process of work hardening. Those same bends made me decide not to use stainless. The system preformed well with none of the stated issues of using hose. In fact because the entire system had been rebuilt performance was vastly better than prior to the rebuild.

 

[heysteve]

Just curious, but do old copper lines actually age out or are they replaced as preventative maintenance? They're malleable enough that I wouldn't think stress fractures wouldn´t be a problem. I see surface corrosion on our 40 year old lines but it's not something I've investigated in detail.

 

[Portage_Bay]

In addition to corrosion copper does get brittle with age. Work hardening. Take a new piece of copper tubing and start bending and straightening it. It will harden very soon. Vibration does the same thing. I have seen a few failures. The ones I remember were right at the flare nut end. Probably due to the lines not being well secured. I think the most common reason to replace old copper lines is when work is due on system components. Then the old copper just won't seal properly when retightend. Or if compression fittings were used, which they should not be, the sleeve won't seal. Overtightening it has indented the line, now the line has to be cut short. And you're working with old brittle copper that won't flare and seal correctly.

 

[Fish53]

In addition to corrosion copper does get brittle with age. Work hardening. Take a new piece of copper tubing and start bending and straightening it. It will harden very soon. Vibration does the same thing. I have seen a few failures. The ones I remember were right at the flare nut end. Probably due to the lines not being well secured. I think the most common reason to replace old copper lines is when work is due on system components. Then the old copper just won't seal properly when retightend. Or if compression fittings were used, which they should not be, the sleeve won't seal. Overtightening it has indented the line, now the line has to be cut short. And you're working with old brittle copper that won't flare and seal correctly.

I used to reuse copper head gaskets by annealing them with a torch, although obviously impractical for tubing.

 

[albinalaska]

Just curious, but do old copper lines actually age out or are they replaced as preventative maintenance? They're malleable enough that I wouldn't think stress fractures wouldn´t be a problem. I see surface corrosion on our 40 year old lines but it's not something I've investigated in detail.

This is technically preventative maintenance as I'm not currently experiencing any issues, or at least I wasn't when we hauled the boat out. I did observed the tubing to be pinched in a couple places for reasons not documented by the previous owner, so it seems prudent to just replace them while everything else is removed from our boat and there is better access now than we can hope for in the future.

 

[albinalaska]

In 2021 I rebuilt the helm pump, steer cylinder, and replaced the lines on my Hynautic system. In my situation, the helm pump and cylinder were the larger size and installed with substandard size lines, which made the system much harder to steer. After consulting with a factory authorized rebuilder, I increased the line size. I'm not suggesting you increase your line size. However, finding hydraulic lines without steel wire in them was quite easy. They're a poly tube with a fabric strength braid (like Kevlar) and an outer cover. The fittings were swaged on at the vendor. I chose stainless steel, but brass and steel were available. I also found online brass fittings to use with the 37 degree JIC fittings.

As I bought the lines on line and changed the routing of the lines, it was important to get the length correct as the fittings would be attached at the vendor. I chose to use a 50' extension cord, but a 1/2" braided nylon line would work just as well. Obviously, just mark the length and measure with a tape measure.

For me, I didn't want any splices, didn't want to fight working tubing around bends, and wanted the easy flexibility that my previous lines had.

Everything worked out perfectly, made the helm easier to steer, and likely will be the last set for the life of the boat.

Ted

Really helpful. What kind of steering system do you have? Our Hynautic manual shows all fittings to the helm, cylinder and autopilot are 1/4" FNPT. Did your unit call for JIC or is this common practice for hydraulic systems?

 

[Bmarler]

Jic is strong, and much nicer to work with. Swivel ends are common too, as are adapters to fpt.

 

[Portage_Bay]

I used to reuse copper head gaskets by annealing them with a torch, although obviously impractical for tubing.

I have annealed copper lines on systems less critical than steering. Anneal, double flare. Pretty good success rate.

 

[O C Diver]

Really helpful. What kind of steering system do you have? Our Hynautic manual shows all fittings to the helm, cylinder and autopilot are 1/4" FPT. Did your unit call for JIC or is this common practice for hydraulic systems?

My helm and cylinder are Hynautic. The helm was a high volume pump that requires 1/2" lines, but the boat builder used 3/8".

At about 20 years old I decided that I needed to rebuild my helm after my buddy's much older helm developed a major leak on the helm shaft. After looking at the schematic, I decided it would be better to let somebody who does it everyday rebuild it. From the distributor, I found a factory authorized rebuilder in NC. After a discussion with him about it being hard to steer, he convinced me to go from 3/8 to 1/2" hose. Both the helm and the cylinder were 1/4" MPT. He drilled and tapped them to 3/8" MPT. 3/8" MPT gives you about a 1/2" hole. The whole bill including drilling and tapping, and the rebuild kits was about $600. Far less than I expected.

I used higher pressure brass fittings. The nipple from the cylinder to the tee was 3/8" to 1/2". The tee and helm hoses were then all 1/2".

My buddy's steering shaft leaking.

My cylinder and plumbing rebuilt.

The difference in hose sizes.

Ted

 

[albinalaska]

My helm and cylinder are Hynautic. The helm was a high volume pump that requires 1/2" lines, but the boat builder used 3/8".

At about 20 years old I decided that I needed to rebuild my helm after my buddy's much older helm developed a major leak on the helm shaft. After looking at the schematic, I decided it would be better to let somebody who does it everyday rebuild it. From the distributor, I found a factory authorized rebuilder in NC. After a discussion with him about it being hard to steer, he convinced me to go from 3/8 to 1/2" hose. Both the helm and the cylinder were 1/4" MPT. He drilled and tapped them to 3/8" MPT. 3/8" MPT gives you about a 1/2" hole. The whole bill including drilling and tapping, and the rebuild kits was about $600. Far less than I expected.

I used higher pressure brass fittings. The nipple from the cylinder to the tee was 3/8" to 1/2". The tee and helm hoses were then all 1/2".

My buddy's steering shaft leaking.
View attachment 168637


My cylinder and plumbing rebuilt.
View attachment 168638


The difference in hose sizes.
View attachment 168639

Ted

Really appreciate the information, Ted! Is that his autopilot shown in the lazarette as well?

 

[O C Diver]

Really appreciate the information, Ted! Is that his autopilot shown in the lazarette as well?

Yes, that's the autopilot pump. If I had done the installation, it would have been mounted on a bracket, on the transom, near the ceiling of the lazarette.

Ted

 

[dqking]

McMaster car has 60 and 100 foot coils of .035 wall copper tube rated at 1000 psi. I would go copper. Your current set up has lasted 40 years and stainless has issues with stress and corrosion in certain conditions. Plus I imagine the copper is easier to handle. On my current boat, I used Parker hose for ease of installation. I have had no issue with it but my vessel is single station and 27 foot.

Plus where the copper connects to other items, there are some kind of fittings. It's lasted for decades so there isn't a dissimilar metal corrosion issue at those connections. Stick with copper for compatitbility.

 

[SeaGator]

You have been fed bad information. I replaced my copper lines three years ago with Parker Racor Marine steering hose. Couldn't be happier. This is on our 1988 Taiwanese trawler with two helms and a 40'+ run to the steering ram and auto pilot at the stern. It is just flexible enough to make the run through hard to reach areas I could never get to with copper or SS. I strongly suggest to read up on the Parker Racor product before you write it off as it is the best option. Ask yourself why no boat manufacturer uses rigid lines anymore. It is not cheap, but your best option. SS is not a good option for sealing fittings as it is not soft enough and copper corrodes.

You will need to have the Parker shop swage the fittings on each end when purchasing for the best results and they do that while you wait and in most cases you can watch them do it. Then it's just a matter of screwing in the new lines and filling and bleeding. Quite simple.

 

[Choices]

If you have ever terminated stainless lines you will know they are hard to get not to weep. Copper is much easier to work with. I have used plastic lines that are used for truck brake and air lines. Super easy to route, wipes clean, no prs issues. Can't remember mfg but look around.

 

[Wtrguy]

Some years ago the potable water industry moved to low lead brass for public health reasons. IMO, low lead brass is far more prone to splitting or cracking under pressure & while tightening, and is a substandard material for high pressure operations.
My question is, when replacing brass fittings on high pressure hydraulic lines, do you source "leaded brass" fittings?

 

[albinalaska]

You have been fed bad information. I replaced my copper lines three years ago with Parker Racor Marine steering hose. Couldn't be happier. This is on our 1988 Taiwanese trawler with two helms and a 40'+ run to the steering ram and auto pilot at the stern. It is just flexible enough to make the run through hard to reach areas I could never get to with copper or SS. I strongly suggest to read up on the Parker Racor product before you write it off as it is the best option. Ask yourself why no boat manufacturer uses rigid lines anymore. It is not cheap, but your best option. SS is not a good option for sealing fittings as it is not soft enough and copper corrodes.

You will need to have the Parker shop swage the fittings on each end when purchasing for the best results and they do that while you wait and in most cases you can watch them do it. Then it's just a matter of screwing in the new lines and filling and bleeding. Quite simple.

Thanks for the info SeaGator. Would you mind sharing the model of hose that you found to work with your steering setup?

 

[SeaGator]

Thanks for the info SeaGator. Would you mind sharing the model of hose that you found to work with your steering setup?

I will post some pictures of it. You can read the print on the hose/tubing. This Parker Racor product is specifically designed for the one application and has an extremely high burst rate.

 

[SeaGator]

I think it's rated at 1,000 psi.

 

[rslifkin]

I used that same Parker hose when I installed an autopilot this year. Easy enough to work with and has done the job just fine so far. It comes in 5/16" and 3/8" ID with a selection of available fittings. Some of the fittings are also available in a field attachable version that can be installed with basic hand tools. I used the field attach fittings on my install with no issues (the 5/16" MSH-5 hose and the seastar tube connector fittings).