wheel needs 18turns from lock to lock???

vas

vas

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as per the title, finaly fixed a leak in steering wheel fluid at the lower helm and for the first time did a full lock to lock (er, a few times to make sure everything is fine...)

Both f/b and lower helm wheel needs 18 turns from lock to lock.
Q, isn't this EXCESSIVE???

I know not much need for using the wheel but I'd expect something in the 5-10turns range not almost 20!
I have a feeling that the pump moving the rudders was replaced at some time (and I make that out of spotting an old pump in the lazarrette...), so maybe they made a mess and installed a larger one. Have to check if I can repair the old one and fit it again, hoping that the A/P will work with it

Ideas?

cheers

V.

PS. MystereMarcus and Pete, if you have any photo of the rudder assembly levers and pump I'd very much appreciate it.
 
Check the capacity of the pump (volume of fluid pumped per wheel revolution) against the volume of the cylinder.

Simple calculation to tell the ratio.
 
thanks for the replies guys, so yet another problem to sort :D

stefan_r: my A/P is a CETREK old jobbie must be 20yo. The control box is 618. In short, I've got no clue if its the one or the other type. Yes there was a serious leak which I sorted and filled up the f/b steering pump with 200-300ml.
Tried turning the wheel, lock to lock a few times, added another 20-30ml and that was it.
Mind the A/P is disconnected at the moment, I could plug it in again and try to steer from it to see if the f/b pump level drops any more.
With the leak I could "feel" when it needed more liquid as the f/b steering was getting dead light and was doing bugger all. Now as you turn the wheel (either one) I cannot hear funny noises and the rudders move nice and smoothly (albeit too slow...)

Spi_D: yes it's probably an easy calculation, but you need to take the damn thing apart to do it, don't you? I'm thinking that the previous owner fitted a larger in volume and piston size most importantly pump as the one that is fitted now is way larger and thicker than the old one I found in the lazarette.

I'll wait for MystereMarcus or Pete's photos and info before I go about ripping things apart, but will try the A/P trick to make sure no airlock is in the system.
I guess all air comes out at the highest point, or should I also bleed at the pump end (by the rudders)?

cheers

V.
 
You'd normally find make & model on a label on the device. Sometimes even a hint on specs, but else that must be googled.

I wouldn't be prepared to dismantle just for that info
 
Before getting too worried , be certain all air is bled out.

run the auto pilot, to steer right, and while doing so steer left this will circulate the air to the upper steering position, assuming it is higher than the auto p. repeatedly top up. then blead the ram on the rudder.


on my steering an indicator of air in the system is that steering wheel bounces back a bit when turned rapidly.

ps I only have a single station, so you need to do the circulate trick more times.
 
Last edited:
Vas,

Mine only has 4 turns lock to lock so your 18 sounds way too much.

I've not really had cause to examine the steering too closely as it's never been any trouble, however I have had that notchy feel to the steering which is cured by adding more oil to the system. This is a bit of a pain because you have to fill it from behind the pump at the back of the wheel (only ever done from the f/b).

Basically the pump drives the ram mounted in the lazarette which moves the starboard rudder, and the port rudder is connected by a steel bar, all pretty basic. I can only bleed the system of air by disconnecting the pipe from the ram and turning one of the wheels.

I'll protograph it for you when I'm next on the boat, but thats my basic understanding of it so suspect you have a leak somewhere perhaps?
 
Vas, I also need to do quite a few turns from lock to lock,
don't remember how many,
perhaps this is typical for older systems on older boats,
will check it when I'm at the boat next week.
 
My 30 year old Princess/Vetus set up needs quite a few turns lock to lock but I've not worried about it as the steering seems fine whilst operational. The flybridge helm pump is very notchy which I would like people to comment on if its not hijacking the OPs thread.
 
Variable displacement pump ....like this one ...

1250_dim.gif


from .... http://www.teleflexmarine.com/products/hydraulic-new/inboard-new/capilano-new/

...think your will be similar to mine ... hydraulic, but not "power assisted" ...
 
thanks for all the comments!

now, did the trick of having the A/P steering one way and me steering the other on either f/b or lower helm. Result was (well when I was on the f/b) that about 30 odd bubbles came up (you can actually see down the liquid level with the filling hole open, quite handy!) and level dropped a bit (50cc max to top up)
Felt more or less the same and with A/P off, measured again and it's still 18turns lock to lock on either helm positions.

Next went down at the lazarette and noticed that the ram currently installed is a BIG bugger with outside dia of over 60mm whereas the one I found lying around is 25mm max... OK, could be that the piston size is smallish and there isn't much volume required to fill it up, but I honestly doubt it.
FWIW, A/P pump is just next to the ram.

Current layout:
steeringram_1.jpg


the label on the current ram (Sleipner Motor AS, Norway, Art.Numb. 71140).
Apparently from the No site I get Sylinder 155 Kgm med ansatsnippler.
Styresylindre for ror og vannjet. The 155Kgm is torque?
Anyone care to comment on that? Note if you change the lang on the site to EN, you go straight to the thrusters site...
steeringram_2.jpg


And this is the old tiny one:
steeringram_3.jpg

The two things that I haven't done (will do tomorrow) is bleed the ram (there were two nipples one on each side but I didn't have a 7 or 8mm key with me to do it), and check for a screw as per Alf's suggestion under the helm mechanism.

For sure the ram looks large, I doubt there's going to be much of an issue with air at the ram side, so took the old one home to dismantle and have a nose around. Looks like it's got some teflon like material at the boxy ends and there is either no thread on the holes or the thread is ripped off. Will investigate further with my glasses on and lots of light :rolleyes:

Extra thought that may affect Bart as well. I noticed on the delivery trip that even pushing the A/P settings to almost max it wasn't following a straight line easily. I remember Bart has had similar problems. So Q for whoever can comment:
Could it be that replacing the ram with a larger one (hence needing to shift LOTS of liquid to move the rudders about) plays havoc with the A/P following course capabilities?

Cheers

V.
 
Divemaster1 said:
Variable displacement pump ....like this one ...

1250_dim.gif


from .... http://www.teleflexmarine.com/products/hydraulic-new/inboard-new/capilano-new/

...think your will be similar to mine ... hydraulic, but not "power assisted" ...
Click to expand...
sorry you posted whilst I was typing.

Yes, they are hydraulic but cannot see how it would be power assisted.
However my helm pumps don't look like yours, will check for the screw tomorrow.

One thing I forgot to mention is that as Glyn-2008 mentioned both my pumps are feeling a bit notchy sort of like somithing holding it a bit every 10-15degrees turning, especially feels on fast wheel turning (which can only be the case with my 18turns...)


cheers

V.
 
vas said:
Could it be that replacing the ram with a larger one (hence needing to shift LOTS of liquid to move the rudders about) plays havoc with the A/P following course capabilities?

Cheers

V.
Click to expand...

When originally put together, the helm pumps and cylinders will be matched, as would the autopilot pump.

If you wanted 5 turns lock to lock you would select the cylinder for the boat, then a helm pump that pumped 20% of the cylinder volume per revolution of the wheel. If you subsequently fitted a cylinder with twice the volume of oil, the helm pump would obviously need twice as many turns.

Same applies to the autopilot, but to a slightly lesser degree. The pump would be roughly matched to the cylinder, any minor changes wouldn't make a difference. But, a big change in cylinder volume would mean the pump would not move the cylinder fast enough.

You need to find out the volume of the cylinder and the model of helm pump (to find out the displacement). Divide the cylinder volume by the helm displacement to determine the number of turns lock to lock. If it works out to 18, there's nothing to do except change some parts.
 
Vas,
The ram does look a lot bigger than the one fitted to mine. The layout is just as Pete has described with the ram attached to the starboard rudder and a bar connecting the rudders together. Photo attached below, hope it's some help.
Marcus.

20121023_135551.jpg
 
Vas,

Your setup with the Sleipner cylinder is very similar to mine (approx 60 mm dia)... and should be built to last ... (us Norwegians usually do a proper job :) ) ... and when translated is for steering of rudders and waterjets up to with loads up to 155 Kgm and having connection points... So overall that cylinder should be OK ... but it does sound like you have a fair bit of air in the system (my flybridge helm had similar feeling when I bought boat) ... remember that the two helm positions are connected, so you need the whole system bled for air....
 
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