Attached are some pictures of bent wing plates on my 32ft Sunsation with full hydraulic steering. The problem is caused by the steering rams not being on the same pivot plane as the drives which causes the rams to want to shorten when the drives are being raised. When there are no steering inputs the rams gets over pressurized and cause the wing plates to bend. Sunsation has a fix but it is somewhat complicated with check valves return lines and all sorts of stuff. It is also for a stock internal steering system. My system has been modified to use both power steering pumps. The dual pump valve is by Latham. The exterior cylinders are by Warlock and the hydraulic helm is from IMCO. Are there any hydraulic experts out there that have a simple solution?
Bent wing plates
Dadinator
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Attached are some pictures of bent wing plates on my 32ft Sunsation with full hydraulic steering. The problem is caused by the steering rams not being on the same pivot plane as the drives which causes the rams to want to shorten when the drives are being raised. When there are no steering inputs the rams gets over pressurized and cause the wing plates to bend. Sunsation has a fix but it is somewhat complicated with check valves return lines and all sorts of stuff. It is also for a stock internal steering system. My system has been modified to use both power steering pumps. The dual pump valve is by Latham. The exterior cylinders are by Warlock and the hydraulic helm is from IMCO. Are there any hydraulic experts out there that have a simple solution?
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Why not use a rod end joint in ss.
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Mark,
The problem isn't with the pivot ends. What's happening is that excess pressure is getting built up in the cylinders when the drives are trimmed all the way up.
Since the pivot point of the rams is located further back, that the actual pivot point of the drive itself, the wing plate is trying to compress the rams as it is being tilted up.
In the crude picture below, the green dot represents the pivot point of the outdrive. The Red line is the steering ram. Try to picture the outdrive tilting upwards and see how the steering ram would be getting compressed. Since the excess pressure has no place to go (locked into the rams... I suppose that says something about the sealing quality of warlock rams!) the force is applied to the wing plate... which in turn, bends.
The problem isn't with the pivot ends. What's happening is that excess pressure is getting built up in the cylinders when the drives are trimmed all the way up.
Since the pivot point of the rams is located further back, that the actual pivot point of the drive itself, the wing plate is trying to compress the rams as it is being tilted up.
In the crude picture below, the green dot represents the pivot point of the outdrive. The Red line is the steering ram. Try to picture the outdrive tilting upwards and see how the steering ram would be getting compressed. Since the excess pressure has no place to go (locked into the rams... I suppose that says something about the sealing quality of warlock rams!) the force is applied to the wing plate... which in turn, bends.
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bayley your pictures never cease to amaze me! seriously that picture helps explain things. however, for proper installation, the pivot point of the outdrive and the steering ram (at the transom) should be on more of a horzontal plane. i believe you have just drawn it that way for clarity, i hope.
i had a nearby machine shop weld & polish some ss plate together to make sort of a stand off box for my ram/transom mounting. i did this about a year ago so i don't remember the exact diminutions but i do remember i needed to do something anyway to get the thru/hull mounting bolts away from the center stringer. i am sorry i don't have any pictures of it off hand or i would post them.
i had a nearby machine shop weld & polish some ss plate together to make sort of a stand off box for my ram/transom mounting. i did this about a year ago so i don't remember the exact diminutions but i do remember i needed to do something anyway to get the thru/hull mounting bolts away from the center stringer. i am sorry i don't have any pictures of it off hand or i would post them.
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Before I got to the bottom of this thread this morning, I was thinking the same thing. Lower your steering rams on the transom. It will at the very least lessen the pressure on the system when drives are raised. If they are lowered to much, the drives will try to pull on the cylinders. there has to be a happy medium some where on the transom. Some what of a cheaper fix too!laster said:
Oh, B can you clean that illustration up at bit, its a good thing I know your boat, because I can't understand what that crude drawing is supposed to be :laugher: :winker: .
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Looking at that first pic, it looks asthough when the drives are up, the steer rams are at a diferent angle than the drive plate which isn't helping anything. If you do lower the rams, I would try to instal a nondiretional bearing in the plate to alow for the diferent angle as the drive raises. But for that you will have to install another tie bar on top of the rams too. Know what I mean? In fact that would fix the plate isue without lowering the rams, but you would still have hyd pressure.
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This is what I mean by a nondirectional bearing. So you see what I mean by needing another tie bar if you put two of these on you plates.
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Bayley your pic helped. I see the problem. The best solution would be a dump vavle thats turned on by the trailer trim button, but that would be a pain in the a__.Lowering the rams would be a big deal and it would just change the direction the wing plates get bent. I would just get some thicker wing plates made. It's the simplest thing to try,but that may just send the load to something else and break or bend it. The rams will get easer to compress with age just because of normal wear so maybe nothing else will break.I'm no expert so this is just my opinion.
Mark
Mark
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If the rams get easier to compress, there is a problem. I don't beleive that to be a comforting thought. Have you taked with Sunsation Bayley?
I talked with Barry about this the day after the Sunsation Rally. He faxed over some hydraulic schematics, but they really didn't make that much sense. Also, his theory on why the wing plates are bending wasn't exactly accurate (to give him credit, I didn't know at the time either). He believed it was more due to one ram still a little bit of extra extension travel left, while the opposing ram was fully compressed. His schematic of hydraulic check valves was for this type of problem. It would probably help the actual problem out as well, but Barry's design was for a single pump setup. Our setup is using both pumps off each engine.
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If I'm understanding you correctly, Bayley, if this was a single engine application, and the steering wheel was held tight, the boat (or bote) would start to turn as trim was changed. This probably happens all the time without anyone noticing. Obviously, twins are another story. I wonder how long this was going on before it was noticed. This can't be the first time that the pivot point of rams were not vertically in line with the drive pivot point.
Come to think of it, I wonder if that would even solve it. If the steering ram were vertically in line with the drive pivot, it still would likely not be in the same plane relative to the transom. Not only that, for a given ram extension, the drive would have to travel in a sideways arc while trimming, unless the steering ram were at the same pivot point as the drive....What gives?
Visualize as if you were on the sunpad, looking down at the situation. Regardless of the vertical location of the steering ram, try to convince yourself that the rams either have to become longer or shorter as the drives trim up or down and stay parallel. There must be something else missing in the way of valving. It's the difference between the rams that gives a net steering input, so if they both get shorter, or longer and the trim is changed, no net directional change has occured.
I'll take my ritalin now.
Come to think of it, I wonder if that would even solve it. If the steering ram were vertically in line with the drive pivot, it still would likely not be in the same plane relative to the transom. Not only that, for a given ram extension, the drive would have to travel in a sideways arc while trimming, unless the steering ram were at the same pivot point as the drive....What gives?
Visualize as if you were on the sunpad, looking down at the situation. Regardless of the vertical location of the steering ram, try to convince yourself that the rams either have to become longer or shorter as the drives trim up or down and stay parallel. There must be something else missing in the way of valving. It's the difference between the rams that gives a net steering input, so if they both get shorter, or longer and the trim is changed, no net directional change has occured.
I'll take my ritalin now.
Brad,
I too am surprised that I haven't heard more about this from other people.
I think the reason why I never saw this before, was because I recently added the tie bar to the wing plate. Before, I used to have the tie bar "saddle mounted" on the trim cylinder mounts. I did notice that the tie bar would get all cok-eyed when I would trim the drives up to the trailer position. I simply shrugged this off as a bad design. Little did I know what was really going on.
I agree that simply moving the ram location further down the transom wouldn't totally eliminate this problem. Sure, it might relieve some pressure by geometrically reducing the delta length of the steering rams, but there would still be an angular change as the drives tilted upwards. I like Dean's idea of having a "stand off" box made up to actually move the pivot point outwards to better line up with the pivot point of the drive itself.
After looking around at some of the other steering kits out there, it seems IMCO has the best geometrically designed system. Their rams tie into the back of the drives on the same plane as the pivot point of the drive. Also, their extension boxes locate the fixed end of the ram further outwards putting it near the pivot point of the drive. If the two mounting points and pivot point of the drive are all in the same plane, then the angle or length of the steering ram shouldn't make any difference.
If anybody has some good photos of other hydraulic steering setups, please post them here so I can see what others are doing. I'm heading over to the barn tonight to do some motor work. I might have to take some more photos of the steering system so I can explore my options.
-Bayley
I too am surprised that I haven't heard more about this from other people.
I think the reason why I never saw this before, was because I recently added the tie bar to the wing plate. Before, I used to have the tie bar "saddle mounted" on the trim cylinder mounts. I did notice that the tie bar would get all cok-eyed when I would trim the drives up to the trailer position. I simply shrugged this off as a bad design. Little did I know what was really going on.
I agree that simply moving the ram location further down the transom wouldn't totally eliminate this problem. Sure, it might relieve some pressure by geometrically reducing the delta length of the steering rams, but there would still be an angular change as the drives tilted upwards. I like Dean's idea of having a "stand off" box made up to actually move the pivot point outwards to better line up with the pivot point of the drive itself.
After looking around at some of the other steering kits out there, it seems IMCO has the best geometrically designed system. Their rams tie into the back of the drives on the same plane as the pivot point of the drive. Also, their extension boxes locate the fixed end of the ram further outwards putting it near the pivot point of the drive. If the two mounting points and pivot point of the drive are all in the same plane, then the angle or length of the steering ram shouldn't make any difference.
If anybody has some good photos of other hydraulic steering setups, please post them here so I can see what others are doing. I'm heading over to the barn tonight to do some motor work. I might have to take some more photos of the steering system so I can explore my options.
-Bayley
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9,049 Posts
Bayley,If you look at pic #10 of my Dominator that Tom
posted in the open forum,you can see the extension
box I had made for the steering rams.I had to extend the mounting points 8 inches to accomadate the Stern
Jacks.
posted in the open forum,you can see the extension
box I had made for the steering rams.I had to extend the mounting points 8 inches to accomadate the Stern
Jacks.
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Has any one tried turning the wheel after the drives have been raised? The reason I ask is because mine (Imco) when I raise the drive after I shut off the engine, and leave the helm, some times I hit the wheel at bit with my leg or arm. And what happens is the wheel will jerk, kinda snap one way a bit. Does this happen to anyone else?
I wonder if that is pressure built up from raising the drive, and turning the wheel at bit, releases it?
Little test Bayley, try turning the wheel back and forth as you raise the drives. With the engine shut off, of course.That sure release the pressure as it builds when your drives raise. Shouldn't it?
I wonder if that is pressure built up from raising the drive, and turning the wheel at bit, releases it?
Little test Bayley, try turning the wheel back and forth as you raise the drives. With the engine shut off, of course.That sure release the pressure as it builds when your drives raise. Shouldn't it?
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It looks like the rams are mounted high on the transom. If you turn the brackets over and reuse the bottom holes and only have to fill the two top holes you will lower the mounts by 2-3 inches and solve your problem.
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