wheel needs 18turns from lock to lock???

[vas]

If you are able to turn it further with constant pressure, afraid the pump or ram are worn out or you have a leak.

thanks David,

trying to get to the bottom of this.
Now that there's no leaks (a minor one on the f/b pump sorted yesterday at the expence of a nice sunburn...) I'm curious!
As you say, if there's no leak, then there has to be a ram issue with fluid slipping from the compression part to the other side, ie piston seals gone.

I'd probably dismiss the case of both helm pumps being worn out (on a med boat I'd expect the lower helm to be used rarely, and it does exactly the same on both stations!)

What still confuses me is that moving the wheel is not smooth it's slightly notchy and I don't get any air/bubbles on the f/b pump.

I'll have a go at removing and plugging the A/P pump and check again. If all's the same, I'll swap rams with the small one and see what happens.

I'll also check if with the ram disconnected the rudders move nice and free (hope so as I cannot waste a couple of days on rebuilding these as well now!)

cheers

V.

 

[PCUK]

Knotchy means air in the system!

 

[david_bagshaw]

unfortunately notchy could be a damaged pump , or ram.

dont forget the lower rudder bearing if fitted is water lubed, so oil it if on shore, before condemning anything.

our steering is particularly sensitive to oil viscosity, and feels much better in the summer, & when the engine room is warm.

 

[vas]

thanks guys,


disconnected the ram from the rudders, rudders arm moves smoothly (er almost as I've removed the trim tabs ram and the tab is resting on the rudders )

further, both wheels move slightly smoother now.
Of course, they can still turn over the end at a rate of one turn per 20secs (yeah, I'm sad I measured it...) Both lower and f/b btw.
So system is definitely problematic and i'd bet my money on the ram.

Also check the schematic of the whole thing, the dotted line is the vent line starting from the lazarette at the a/p pump and going up to the f/b through a t on the lower helm.
check also the small box under the lower helm with a fly type screw on it.
Now, on undoing this screw (even half a turn) both stations are dead. I mean you can turn the wheel to your hearts content, it does bugger all on the ram. So I assume it mixes the two flows and kills them in one go??
Out of curiosity, wtf point in it????

Following a bit of paint stripping in the base where rams/rudders/a/p mount, I found under a good 4-5 coats the holes and stamp of the base for the other ram I restored, bingo!

That brings us back to the point that this small ram (with an estimated 3 turns from end to end) was indeed original equipment (and I presume with the original a/p - assuming there was one!)

Judging from the coats of paint, I'd say around 20+ yrs ago, when they changed the electronics to the state of the art Cetrek (ok, I'm told it was back in the nineties...) they probably used a large a/p pump that fcked up the setup. So in the typical fashion of the PO, he swapped the ram with a larger one...

BTW, checked the photos I took of the other Mystere down here, and indeed the ram looks smaller than the monster I have currently installed. Mind it's a completely different setup with ram and a/p being on the port side, mine's on stbrd.

hope it makes sense, will need a few racor connectors and will test on Monday.

cheers

V.

 

[Otter]

FWIW the Kipper uses ATF the same as in your system and the yard who fixed the system said that was the usual stuff.

 

[david_bagshaw]

would your release screw be so when a emergency tiller is fitted,onto the rudder stock you can steer the boat, and not try to turn the wheels as well.

 

[vas]

FWIW the Kipper uses ATF the same as in your system and the yard who fixed the system said that was the usual stuff.

good to know, I'll have to get another bottle or two. I'll check to see if there's different viscosity ones (I doubt!)

would your release screw be so when a emergency tiller is fitted,onto the rudder stock you can steer the boat, and not try to turn the wheels as well.

ah, makes sense. I'm planning to drill a hole in the aft deck (when I restore it that is) and keep an emergency tiller in the lazarette


Out of curiosity, if indeed my problem is the LARGE A/P pump and if it turns out that it's not adjustable, can I just get another adjustable pump and use it with my Cetrek for the time being and until I decide to update all the A/P stuff to something else (most likely Garmin gear?)
I'd have thought the A/P pump is just that, three cables and two pipes (plus the vent one)

Or can I get a flow reducer for the pump I wonder!

anyway, tomorrow I should know if it works with the old pump without being extremely heavy steering and without leaks.

looks like it's getting close to sorting this one out as well...

cheers

V.

 

[david_bagshaw]

In theory some excess pump volume could be released by some extra control valves. An untidy, more complex and risk of failures and probably cheaper and definitely better to have the correct sized total setup.

 

[vas]

success!

er, almost, well, got the old ram in place, original holes, screws everything.
Wheel is reasonably light (anyway, same feel as the 18turn version) BUT lock to lock is 3.5 turns!!!

so, yes, that's the one.

the small catch is that there's a tiny leak in the ram faceplates holding the whole thing together, tightened it too much, ripped a thread on one of the 4 long bolts keeping it together, today got all the bits I needed to redo it, did it, leak stopped, after cleaning carefully all the mating surfaces (MIND THERE'S NO GASKET/seal!) but I stupidly reassembled the other side wrongly, so got to open it up a third time and fix it tomorrow.

So next issue to solve is the A/P pump, it is a big thing, will have a look around for specs and see what I'll do. From checking in the control box nearby, it's just a red and a black thickish cables into the motor, so I guess it's just reversing polarity and driving the pump in or out, correct? Also means it should be easy to find another smaller pump for me if I cannot change/strangle flow. It's this:

Anyone familiar with Fracmo?

Managed to undo both the large and the small screw on each side of the pump body, just oil started seeping out from the small one, got scared and didn't remove the large one completely.
Bought two plugs for the T junction and planning to disconnect the pump, bring it home and check it out at leisure.

cheers

V.

 

[vas]

being the original poster I guess I'm allowed to revive a 2.5yo thread

after the gbox failure on Sat and the return trip of 25nm on confused seas with only the stbrd engine running and rudder basically 90-95% to stbrd to keep a straight line, I'm back to the ram/pump/pipework topic as on certain occasions even when both engines worked properly steering was becoming horribly heavy and wouldn't respond well due to (I believe) lack of appropriate rudder movement.
Did the tests again, yes I can reach the end of the travel and keep on turning the wheel (with moderate force but nothing excessive)
Favourable solution is to assume it's the ram (cheap to try and rebuilt it again!), nasty solution is having to remove both station pumps and rebuilt them (slightly messy) and everything in between.
Trying to eliminate the ram case, I'm planning to fit two stop valves on the main copper pipes coming down (just before the flex hose feeding the ram) This way I can do alterations back there without having to empty all the fluid.
Furthermore I can also test if the fault is at the ram, as if the same behaviour continues with the two valves closed, it cannot be (or wont be only) the ram!

Any objections on having (I guess I'll find proper spec) valves on the main pressure lines?


If it's not the ram, I'll try and remove the f/b pump and take it apart, but I'm worried it may be the flywheel box not blocking properly the routes and mixing up and down oil reducing the pressure to the ram...

Thinking of going one step at a time here as I've also got a gbox issue to sort

cheers

V.

 

[rgarside]

Some useful information here:-
http://www.phoenixhydraulics.co.uk/Products/Marine-Hydraulic-Steering

 

[vas]

Some useful information here:-
http://www.phoenixhydraulics.co.uk/Products/Marine-Hydraulic-Steering

thanks!


quite a lot of things in this site.
Plan is to manage and reuse/refurbish and have the system running with minimum new expenses, but not always the case

cheers

V.

 

[vas]

and a year and a half later, or 4.5 years after the first post on this thread, I have a working hydraulic steering system
talking about speed here... well impressed I must say!

So, the old rebuilt ram was used over the last two years, originally without an a/p and since Sept last year with a brand new garmin a/p. Meant new flex hoses and taking apart and refitting the lot.
However, both years steering was sloppy, boat would keep track (generally) but after a while it would tend to steer to port and I'd have to counteract again and again.

Wasn't happy, but had all sort of other issues to fix and projects to complete...
Anyway during Oct (iirc) I tried to have another look at the steering ram as I spent an hour going in circles trying to "train" the a/p unsuccessfully. What I realised is that I could (with some force, but not anything excessive) move the bar connecting the two rudders (and the ram of course!) This play was substantial as in about 30-40% of the whole travel
Something obviously wrong there and further I had a small leak on the stbrd side faceplate of the ram. So took it apart, got it to the machinist who concluded that the new end seals weren't up to the job. Trying to find stronger ones proved difficult with the only ones found being larger (outer diameter). Decided to machine the bronze end plinths of the thing and fit these larger seals.
Vangelis put it back together and sweared it's never going to leak again. Slightly worried that the ram was rather stiff and was difficult to shift about, got it in place in Nov.

Cut a long story short, after a month of back problems and 2-3 weeks with polar conditions, I only today got the courage to go to the boat and do some work as it was sunny with temps up to 15C.
Tightened all up, filled with ATF and started turning the wheels port stbrd for half and hour moving from lower to upper and vice versa, filling oil and having a few bubbles now and again (visible on the upper wheel filling point)

Checked again the bar between the rudders and unsurprisingly had a substantial play again
Rather disappointed was about to take it apart and find a solution on the piston seals (assuming that oil was passing from the one chamber to the other)

As a last test I turned on the a/p engaged it and used the arrows to move the rudder port and stbrd in a similar fashion.
Checked the level and had dropped substantially and the lower helm wheel stiffened and became more responsive with fewer notches.
Kept another half hour going all three steering points port to stbrd checking and filling oil until I run out of time!
Checked again the bar, no play
Cannot believe that actually bleeding a 43ft f/b mobo hydraulics takes almost 2h, ffs!!!
BTW, Vangelis was right, no leaks either!

So morale of the story if steering feels notchy and/or ram has some play (or a lot!) before writing off the system as problematic, please spent an hour or so playing with all wheels and a/p to clear up the air off the system. That is if you have a smallish ram without bleeding nipples, otherwise, just bleed the thing first!
BTW, now system went down from 3.5 turns end to end to 3 turns (3.05 to be more accurate) which is actually close to my calculations at the time.

cheers

V.

 

[rbcoomer]

Wow! 10/10 for persistence! :encouragement:

 

[BartW]

Vas, I admire your perseverance !

 

[vas]

Wow! 10/10 for persistence! :encouragement:

Vas, I admire your perseverance !

comeon guys, I was so happy after endless hours of thinking and trying to figure out wtf is wrong with this system and anyway I'm too tightfisted to spend money on a third ram, so I had to fix it! BTW, total cost was around 15euro for the seals and another 20 to Vangelis to machine it.

Persistence and perseverance my arse!
I should have you steering MiToS without a/p, badly fouled hull doing 8kn for 5 hours and then I'd see if you'd like the steering sorted or not

Main reason for my last post on this thread was to stress the importance of bleeding the bleeding system as any normal person would expect that after half an hour faffing with both wheels system should be OK, but it wasn't! Needed messing with the a/p going port and wheel to stbrd (and vice versa) to fizz all the air out.

Anyway, few more jobs to do, so will try and post on the main thread this w/e

cheers

V.

 

[rafiki_]

Good result Vas, and wise words.

 

[Phildorset]

great account of a problem sussed out and solved, thanks for sharing - it's certainly helped my understanding of how my two helm set up (probably) works.

 

[vas]

glad to be of any help and return whatever I can to the forum.

What I'm actually now realising is that if someone has a hydraulic dual helm system with any problem like that, he's not going to find this thread by searching on the forum...

Maybe a change of title is in order.

cheers

V.