Do my eyes deceive me?

johnma said:

there is one high pressure hose end used in this application it is the bottom left fitting on the valve block. If you look closely you can see it is a lighter color than the rest and it is round where it goes over the hose rather than having wrench flats. that is because it is crimped on rather than screwed on. Some of the other screwed on fittings are hydraulic and some are pneumatic. The hydraulic ones will have a slightly longer body. Hydraulic fitting flares are on a 37 degree angle and pneumatic are on a 45 degree angle so they match the mating fitting. the two types are not interchangeable.
The elbow on the left port of the cylinder is rated for 200 psi air.
I'm the senior engineer for the mid Atlantic and New England Eaton Hydraulic distributor.
John

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Wow - thanks for that explanation. I can clearly see the difference in the high pressure fitting but I'm having trouble distinguishing between the screw-on air and hydraulic fittings - can you point that out for me? I can see two different styles of - I'll call them nuts - on the T fitting at the inboard end of the cylinder. Is that T a different spec than the L coming out of the top of the cylinder?

One other thing I noticed - the cylinder end of the hose going to the shadow drive appears deformed right next to that fitting going in to the T. That is exactly the kind of vulnerability I was envisioning.

I think some people on this forum could down load the sea star/ hynautic catalog and refine their opinion...

All of the fittings appear to be correct and are in the catalog. I would guess that the piece of tygon tubing is there as an anti-chafe that has slipped down the hose a bit. It is probably supposed to be adjacent to the ram mount. Long loops of hose (within reason) make for longer life.

if you look at the far left hand hose that has the wire tied to it you can follow that hose down to the the black valve. the hose end is clearly much lighter in color than all of the others, and as I said earlier it is a crimped fitting that is assembled in a machine. All of the other hose ends are two piece and are hex shaped where they go onto the hose. When assembling the collar onto the hose you use this hex shape for your wrench and it is a left hand thread. once it is on tight to the hose you take the the hose end itself and screw it into the hose. It has a right hand thread. the collar for high pressure (2000 psi) hose is longer than these.
next, look at the elbow on the left side port on the cylinder. They have an elbow, plus a tee plus a fitting screwed into each port on the tee that the hoses screw onto, If you compare that to the elbow on the right side port you can clearly see that it is not the same set up. the right side tee would be original and the left side set up uses 4 fittings to do what they did with 1 on the right side.
lastly, if you look at the far left side hose with the crimped fitting you can see that it goes into an elbow and then right into another elbow where it screws into the valve.
No manufacturer in there right mind would use this wide variation of fittings. The elbows are brass and are used for air brake systems on trucks. Should not be used for hydraulics.
John

Brass flare fitting and SAE (45 degree) flares easily capable of taking pressure generated by that system. Commonly, but not always, brass fittings are SAE flares, steel are JIC (37 degree) which does make one wonder about that one steel hose fitting attached to the brass fitting on the pump.
Funky looking plumbing job, I better go look at mine again. Hopefully it's better looking.

my biggest concern is the low pressure fittings and tee, not as much the hose ends. The tee on the cylinder is npt. they do not make those in sae oring. the adaptors are bottomed out in the tee. no threads are visible. as we all know, npt is tapered and a fitting should turn in 1-1/2 to 3 turns by hand before tightening with a wrench. These are all the way in. this is a definite failure point and definitely not original.

Not to belabour a point, but seastar, capilano, teleflex and hynautics use a hodgepodge of NPT, tube, 37 JIC and 45 flare fittings. They recently added O ring boss fittings into the mix. Silly enough, the helm pumps and rams only recently went to ORB; it must have been a bugger getting the desired orientation with NPT fittings. One page of any of their catalogs show the mixture of fittings going on. It is probably due to the organic growth of home businesses which have merged and split off many times, while trying to maintain legacy parts for previously built systems.

If these fittings are made to a standard, such as SAE J514 or ASME 31.3, they will easily handle the 1000 psi rating of the system, as the IDs are so small, usually 1/4" and 3/8". I'm sure the operation pressure is much, much lower.

That said, it is really hard to armchair quarterback a photograph. I have been burnt a few times by asking to troubleshoot from a photo. Field visits reveal so much more information...

Northern Spy said:

If these fittings are made to a standard, such as SAE J514 or ASME 31.3, they will easily handle the 1000 psi rating of the system, as the IDs are so small, usually 1/4" and 3/8". I'm sure the operation pressure is much, much lower.

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Are you implying that a smaller area somehow changes the pressure (expressed as force over area)?

And what makes you believe that pressure does not go to 1000 psi? That's the pressure specified by SeaStar for bleeding their system - it's not possible to commission a system that won't hold that pressure. Are you thinking that because most of the time the system isn't pressurized that somehow an average pressure becomes relevant?

Also, note that 1000psi is "minimum operating pressure" for Capilano/Teleflex/SeaStar hydraulic hose. The "burst pressure" is 5000psi.

Most hydraulic hose and fittings are rated for higher pressure in the smaller sizes

On another note, is the ram mounted on a piece of star board? If so that is not strong enough.

Thank you all for your thoughts on this installation. I was originally concerned about the overall layout and lack of tidiness - plus whacky tubing and the obvious vulnerability - but I've learned a fair amount about fittings along the way. I also received a PM from an professional installer agreeing about the sloppiness and pointing out the lack of critical isolation valves. It's a bit more than a thought exercise for me because I'm going to be tearing into my own hydraulic in the next off season.


Keith

Tingum said:

On another note, is the ram mounted on a piece of star board? If so that is not strong enough.

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Yeah it looks like 1/2" with a few 1/4" screws/bolts. That stuff deforms over time but it appears it was a standard GB practice.


Keith

The stress put on it is directional.....ever hit the edge of a pane of glass? Pretty dang strong.

Run the numbers on strength and what is required and yep....probably worked fine for years because it is strong enough.

refugio said:

Are you implying that a smaller area somehow changes the pressure (expressed as force over area)?

And what makes you believe that pressure does not go to 1000 psi? That's the pressure specified by SeaStar for bleeding their system - it's not possible to commission a system that won't hold that pressure. Are you thinking that because most of the time the system isn't pressurized that somehow an average pressure becomes relevant?

Also, note that 1000psi is "minimum operating pressure" for Capilano/Teleflex/SeaStar hydraulic hose. The "burst pressure" is 5000psi.

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Fittings typically don't have proportionally thinner wall as the diameter decreases. So as the mean diameter decreases, so does the hoop stress generated by internal pressure. You will often see small diameter fittings with a much higher rating than larger diameter fittings.

Yes you can generate high pressure by cranking the helm into the rudder stops, but normal operating pressure of the helm is a fraction of the tested pressure. Most systems have have reliefs at 900-1000 psi to prevent seal damage.

SAE 100R hose was the typical hose used before vendors came up with specialized hose.

I too like isolation valves, but they can be a curse, as they are often just another leak point later. I would want a cylinder bypass valve for bleeding, and emergency rudder control though.

I know nothing about starboard. Never used the stuff.

psneeld said:

The stress put on it is directional.....ever hit the edge of a pane of glass? Pretty dang strong.

Run the numbers on strength and what is required and yep....probably worked fine for years because it is strong enough.

Click to expand...

I don't think you're getting it, the whole system is about to explode any minute now.