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Steering Failure after Sailing

4K views 27 replies 9 participants last post by  LittleWingCA 
#1 ·
Hi Everyone:

I had an interesting event occur last Sunday while out sailing my Pacific Seacraft Orion 27 in San Diego harbor. We had very good wind, and were able to get up to 5.5 knots sustained speed most of the day. There were a lot of boats out, so we did get tossed around some by wakes, etc. but nothing I would consider abnormal, or unexpected of being out on the water. While motoring back into the marina, my hydraulic steering system failed, and for a few brief minutes was left drifting into the marina until I was able to rig the emergency tiller and regain control. Very scary at first, since we were about 4 boat lengths away from either running into other tied up boats, or hitting the waste pump out dock, depending on the direction of the rudder when the steering failed. I used the motor and a combination of forward and reverse to avoid hitting anything while my wife dug out the emergency tiller and then I got it installed on the rudder post. Luckily disaster was averted, but now I need to figure out why the steering failed and what to do about it.

Some History:

Last year about May, I had a local Marine Service company replace my worn out 27 year old rack and cable steering system with a new semi custom hydraulic system. Since my steering pedistal is mounted on my hinged engine access cover, a normal wire cable system can't be fitted, since when opening up the engine cover, the entire pedistal rotates with the hinged cover, and the hydraulic system looked like the way to go. I also couldn't find a replacement rack and cable system on the market heavy duty enough for my boat.

I had heavy duty Marine grade parts, pumps, hoses, etc. sized for the boat, and some custom mounting hardware made up, and powder coated to resist corrosion. All worked well for a little over a year. After getting back to the slip safely, I opened up the engine cover and saw that the connection from the hydraulic ram to the swivel fitting on the tiller arm were separated. This is a threaded connection. Not sure yet if they became unscrewed, stripped out, or if the swivel fitting simply broke / sheered.

The guy who designed the system is a 20+ year experienced Mechanical Engineer who has been doing Marine work for a very long time. He came highly recommended, and did a awesome design job. What I need to figure out is if this is just a random component failure (infant mortality) or a bad design or part selection issue. Not sure how to determine if the forces on the rudder during normal sailing were more than the fitting could handle, or if alignment might be to blame, etc.

Any thoughts on where to start the investigation, or what questions to ask the Engineer after he comes and takes a look at the problem? I am a Electrical Engineer by trade, but this mechanical linkage / force, strain stuff is a little out of my area of expertise, but I understand how to troubleshoot when I have a little background information. I would appreciate any feedback or suggestions on how to make sure this doesn't happen again, especially when offshore, and how I can guarantee a sturdy steering system.
 
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#2 ·
You ask ;
"Any thoughts on where to start the investigation, or what questions to ask the Engineer after he comes and takes a look at the problem?
I would think you would want to start;
"the connection from the hydraulic ram to the swivel fitting on the tiller arm were separated."

I am having a hard time picturing "the connection". Is it a threaded nipple that is screwed into the hydraulic swivel?
Did it break at the threads?
Could you post a picture?
 
#3 ·
well, sounds to me like you already know what the problem is - your ram got disconnected from the tiller arm.
On my boat this connection is a fork on a ram that fits over tiller arm, and is connected with a beefy clevis-type pin (about 1/2" diameter, I reckon).

Actual hydraulic steering failures would probably be slower to develop (unless a hose or connector fails catastrophically and all the fluid leaks out). Otherwise, slow leaks would make system feel spongy and unresponsive for a while before it gives up completely.
 
#4 ·
well, sounds to me like you already know what the problem is - your ram got disconnected from the tiller arm.
On my boat this connection is a fork on a ram that fits over tiller arm, and is connected with a beefy clevis-type pin (about 1/2" diameter, I reckon).

Actual hydraulic steering failures would probably be slower to develop (unless a hose or connector fails catastrophically and all the fluid leaks out). Otherwise, slow leaks would make system feel spongy and unresponsive for a while before it gives up completely.
After reading the original post again, I saw that he wasn't talking about a hose connection or a hydraulic fitting at all. :(

I think you response is right on. If you know what failed it should be pretty easy to correct the problem.
I think that there are times where the numbers on something might work on paper but not so well in the real world. If something fails, beef it up.
 
#5 ·
The hydraulic system itself is fine. The ram still moves linearly when the wheel is turned. The break occured at the fitting between the hydraulic ram and the tiller arm. The problem is why?

My rudder post is angled slightly aft (off vertical) as it runs from the cockpit through the engine compartment through the hull. The tiller arm attached to the rudder post therefore swings in a semi circle (as is normal), but at a slightly elevated angle to a horizontal plane due to the tilt of the rudder post. On the end of the tiller arm is a ball, like that on a trailer hitch. The hydraulic ram has a threaded end that received the swivel fitting that attaches to the ball on the tiller arm. This allowed the linear motion of the hydraulic ram to actuate the tiller arm. The ram cylinder itself is mounted on a dual axis fitting so it can move up and down and left to right as it actuates the tiller arm to match the swing of the tiller arm along its angled arc.

The swivel fitting is still attached to the ball on the tiller arm, so the failure occured at the threaded connection to the hydraulic ram. The problem is why? If I just need to "beef" up the swivel fitting, the question will be, by how much and how do I know when enough is enough without waiting for it to break again to find out if it was enough? Any thoughts?
 
#6 ·
If I just need to "beef" up the swivel fitting, the question will be, by how much and how do I know when enough is enough without waiting for it to break again to find out if it was enough? Any thoughts?
Beef it up just about half again as much as you think you need to and keep the emergency tiller handy. :)

Seriously, how can anyone speculate without at least seeing what you are talking about.
Post some pictures and we would have an easier time of it.

But bottom line, wouldn't the guy who designed and built this system be in the best position to troubleshoot the problem and correct it?
 
#7 ·
Knothead:

I will get some pictures so you can see what I am referring to.

I have already called the guy who designed the system to have him come and check it out, but since it has already failed after roughly one year, there is some doubt about whether he knows enough to fix it properly this time. Hence why I am posting this issue to see if others have had similiar experiences and to see what they did to resolve it. Maybe I will get lucky and find another Maritime Engineer on the forum who might have some suggestions. Let me see if I can post some photos.
 
#9 ·
In every hydraulic steering set up I have seen the end of the cylinder is a clevis (fork) that goes over the steering arm with a bolt or pin through it. The other end is usually solidly mounted with another clevis that allows for vertical movement. If the ball joint you mention is what I envision I would change to a much more substantail connection to the arm.

John
 
#10 · (Edited)
Brak:

I pulled the invoice for the job now that I am home. The hydraulic pump is a Kobelt 7003 series driving a Marol MSC-28 series linear cylinder with a 82 SER - FEM JIC Swivel attached to the end of the ram.

Jrd22:

The swivel was done because my tiller arm already had the ball fitting on it from my old rack and cable system. The failure is at the ram and swivel connection. The swivel is still attached to the tiller arm, so it looks like the threaded interface between the swivel and ram is what failed. I will have to check and see if the swivel still freely moves on the ball. We have been sailing every weekend for the last 6 weeks, with no trouble until now.

It looks like the swivel is the weak link in the system. The only problem I see with not using a swivel is the non horizontal angle of the tiller arm. A Clevis / Fork might only work if the plain of the tiller arm and hydraulic ram are the same. My setup has the ram capable of 2 axis' of freedom to account for the angled travel of the tiller arm.
 
#12 ·
So the female threaded swivel fitting came away from the ram actuating arm?

Loctite maybe. If it was fit dry, then the fitting could come off with a years worth of back and forth. The only trouble I'm having in visualizing that is how exactly the fittings are that one would be allowed to turn 360 degrees without binding on another fitting.

Perhaps the hydraulic ram arm is able to spin freely in the ram body. Can you grab the ram arm and spin it with little resistance? If that is so, then there is where the free spin culprit might be. Otherwise I don't know how a threaded fitting could come unthreaded in a fairly static setup. If the ram arm can spin in the body then you may need loctite or a similar thread locker to keep the whole unit together.

Maybe a mechanical solution is called for. If the hydraulic arm and swivel are beefy enough, maybe you can drill through both and put a keeper bolt through. If not, maybe two shallow taps 90 degrees apart to put set bolts in (like your prop shaft and coupling have).

Of course, that is if I'm envisioning this all correctly, if not:confused: :confused: :confused:
 
#13 ·
Sapperwhite:

Yes, the Swivel fitting separated from the ram actuating arm.

The tiller arm on the rudder post can't travel 360 degrees. Maybe between 90 and 120 degrees max to get full rudder swing. Since the swing of the tiller arm is angled relative to the horizon, the hydraulic clyinder ram must be able to move up and down slightly, as well as left and right slightly to prevent any binding as the tiller arm moves.

I didn't notice any loctite on the threads, and I will have to check to see if the actuating arm of the hydraulic cylinder can rotate in the cylinder or not. If it can, this might explain how it unscrewed itself over time. If that is the case, some loctite and a hole / cotter pin modification might do the trick.

If the female socket on the swivel is broken, sheered, or stripped out, then I have a bigger issue which is probably either design or alignment related some how.
 
#15 · (Edited)
I know exactly what the steering gear area looks like. I've spent quite a bit of time upside down through the cockpit running new plumbing, wiring, engine work, steering gear work, new waterlock, etc. etc. I know what you mean about the angle. My Orion was built with wheel steering, did you convert from tiller to wheel?

Here is a pic of my steering quadrant (Orion wheel cable steering) . Nevermind those rusty hose clamps....old pic.

 
#16 ·
Sapperwhite:

My Orion 27 supposedly came from the factory with wheel steering using a rack/pinion and cable connection from the wheel to the tiller arm originally. This was due to the pedestal being mounted to the engine cover on the part that opens up. The previous owner damaged the cable one day when it touched his exhaust elbow before he added a heat blanket. By the time I purchased the boat, water and corrosion were creaping into the cable and making steering very stiff. I had the rack/pinion and cable system replaced with a hydraulic system.
 
#17 ·
The ball joint usually canot be seperated. It has a bolt to attach it to whatever and a female end to accept the threaded end of the ram's shaft.

The ram has a round piston and round shaft and no way to index it. The shaft near the threads usually has flats ground to allow you to fit a wrench to hold the shaft from turning .

If the ball joint came unscrewed from the shaft I am going to guess it is because the JAM NUT was not installed.

Even if the shaft unscrewed from the ball joint the jam nut should still be on the shaft in the short time you described between failer and inspection.

Just install a jam nut on the shaft screw the shaft back into the ball joint, check operation, Hold the ball joint and tighten the jam nut up aginst the ball joint.

Done

You can take a bit of Testors paint and put a drop on the top of the three parts in a line to make a quick check to see if all is well.

Rick
 
#18 ·
If the ball joint came unscrewed from the shaft I am going to guess it is because the JAM NUT was not installed.

Rick
My guess is Rick hit this exactly. Pictures will tell the final story but matches my experience on industrial hydraulics.
 
#19 · (Edited)
I remember seeing a large nut still on the ram actuating arm. This must be the Jam nut. Maybe it was never tightened up against the ball joint. I guess I will need a lock washer as well. The opposite side of the ram has flattened surfaces to attach a wrench, so I guess the ram actuating arm is designed to be able to rotate in the cylinder body, which could explain how it unscrewed over time.

Sounds like a little loctite, lock washer, and screwing it back together along with tightening up the Jam Nut may be the fix. I should also probably cut an inspection port hole, with water tight cover, in the cockpit floor to be able to keep an eye on this connection over time without having to lift the engine cover. I like the idea of a line of paint to see if things are moving.

I will post pictures this weekend when I get a chance to get back to the boat.
 
#21 ·
I should also probably cut an inspection port hole, with water tight cover, in the cockpit floor to be able to keep an eye on this connection over time without having to lift the engine cover. I like the idea of a line of paint to see if things are moving.

I will post pictures this weekend when I get a chance to get back to the boat.
If you want ideas about quadrant/steering gear inspection ports, take a look at "Green In Between" photo album on the Orion Yahoo group, they have some nice ones.

I sometimes use a sharpie to mark a line across the fitting and the "fitted" to see if the bolt/screw/fitting is backing out over time.
 
#20 ·
I have never had to use a lock washer but if it will make you feel better than that's fine.

I would not install an inspection port. Just check it before you go out the next couple of times and then when ever you open the cover for engine maintainance.

Rick
 
#22 ·
While motoring back into the marina, my hydraulic steering system failed, and for a few brief minutes was left drifting into the marina until I was able to rig the emergency tiller and regain control. Very scary at first, since we were about 4 boat lengths away from either running into other tied up boats, or hitting the waste pump out dock, depending on the direction of the rudder when the steering failed. I used the motor and a combination of forward and reverse to avoid hitting anything while my wife dug out the emergency tiller and then I got it installed on the rudder post. Luckily disaster was averted
I know nothing of the fix, however I would like to completment you on the seamanship.
 
#23 ·
Photo Update

Finally got some pictures to share on the steering failure. It appears the failure was caused by the hydraulic ram simply unscrewing itself from the swivel fitting. After re-aligning the ram and swivel, I was able to just rotate the ram and screw the system back together. This time I added the loctite blue thread sealer which I hope will keep the connection together. I also added other pictures of the hydraulic setup since some of you asked. The chain is attached to the wheel, and works the hydraulic pump which powers the ram / cylinder. Very simple, doesn't require any power, and hopefully will stay together this time.
 

Attachments

#26 ·
Finally got some pictures to share on the steering failure. It appears the failure was caused by the hydraulic ram simply unscrewing itself from the swivel fitting. After re-aligning the ram and swivel, I was able to just rotate the ram and screw the system back together. This time I added the loctite blue thread sealer which I hope will keep the connection together. I also added other pictures of the hydraulic setup since some of you asked. The chain is attached to the wheel, and works the hydraulic pump which powers the ram / cylinder. Very simple, doesn't require any power, and hopefully will stay together this time.
If it were mine, I would drill through and pin the thing. Locktight is good stuff, I use it all the time. But what you have, I would pin as well.
 
#24 ·
Thanks for the update. Did you tighten the jam nut as well???
 
#27 ·
yep, I second knothead on that one. however, I think it needs to be drilled professionally to avoid reducing strength of material too much.

Interestingly, my steering ram arm does not rotate (and does not move externally when ram is empty, or at least not by hand).
 
#28 ·
Brak:

I have a bypass valve in the system which allows the wheel to be "disconnected" from the system and the ram can then move freely with the hydraulic fluid just moving from one side of the ram to the other without going through the pump. This was added to allow the use of an emergency tiller if the pump, drive chain, or wheel failed. The ram itself can rotate 360 degrees at any position setting, which I assume is proper since it needs to thread into the swivel fitting. The lock nut is supposed to prevent it from unscrewing itself, but I guess the original installation either wasn't done correctly, or it worked loose over time.

The Engineer who designed the system finally called me back after 2 weeks and went down to the boat to inspect the setup, and my fix, and checked to make sure the lock nut was properly tightened. He was very surprised as well that it unscrewed itself, and apparently this was the first time one of his hydraulic installations did that. I will ask him about adding a pin to prevent it from backing out in the future.
 
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