Possibly/Probably disastrous steering problem :(

Bobobolinsky said:
You need to pivot the ram, otherwise it just moves up and down the shaft :eek:
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As salacious as this sounds... Sorry, I don't follow?

Imperial pipe fittings are still quite standard all over the world.
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Good news!

For emergency steering, you will need a valved crossover line between the in and out hoses (close it and remove the handle, so it does not get accidentally opened, handle chained to the valve and then taped in position, or it will clap like a bell). Open valve for emergency steering and then a simple tiller on one rudder. If you don't have a crossover line, you need a much longer tiller to overcome the steering pump.
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This is another thing I'm hoping to do when I properly sort out the emergency steering situation. There's a couple of other improvements I wish to make to the hydraulic system, also.
 
You don't need to weld, only drill the rudder bracket. The cylinder I linked to comes with an angle bracket for mounting, simply get another one (or equivalent), through bolt it to the rudder and bolt the ball joint to that. Welding IMHO is not as robust as through bolting in this case. Bolts can be checked, maintained and worst case replaced mid voyage, a cracked weld can't.

Yes, you could keep the existing ram as the rudder link rod. Not pretty, but certainly effective. As a quick fix its fine, but personally I'd look to fit a proper link rod at some point... Time and finance permitting of course!!

For the emergency tiller, fit a valve between the two fluid lines of the ram. Open the valve, and the ram and hydraulics are bypassed.
 
With respect to throw, measure the linear length of the arc described by the rudder attachment. DO NOT get a ram that exceeds this distance, as the hydraulic force will be enough to bend and break bits if the rudder travel hits its limit before the ram is fully extended / retracted.

Rams come in fixed lengths, so the mounting on the rudder should be moved fwd or aft until the arc length is the same as or slightly longer than the ram travel.

The three turns lock to lock is the slightly tricky bit though. It's a function of the area of the piston and the throw v attachment point on the rudder. Do you know the make of helm unit? It would help to know the volume of fluid pumped per turn of the wheel..
 
rosssavage said:
You don't need to weld, only drill the rudder bracket. The cylinder I linked to comes with an angle bracket for mounting, simply get another one (or equivalent), through bolt it to the rudder and bolt the ball joint to that. Welding IMHO is not as robust as through bolting in this case. Bolts can be checked, maintained and worst case replaced mid voyage, a cracked weld can't.
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Cool, thanks.

Yes, you could keep the existing ram as the rudder link rod. Not pretty, but certainly effective. As a quick fix its fine, but personally I'd look to fit a proper link rod at some point... Time and finance permitting of course!!
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We're planning to stop in Spain for a month. That will give me a chance to sort out the link rod and emergency steering properly. I'd just like to get things to a safe point until we get there.

I don't suppose you could give your thoughts about ... I think you just replied, I shall give a read! :p
 
rosssavage said:
With respect to throw, measure the linear length of the arc described by the rudder attachment. DO NOT get a ram that exceeds this distance, as the hydraulic force will be enough to bend and break bits if the rudder travel hits its limit before the ram is fully extended / retracted.

Rams come in fixed lengths, so the mounting on the rudder should be moved fwd or aft until the arc length is the same as or slightly longer than the ram travel.

The three turns lock to lock is the slightly tricky bit though. It's a function of the area of the piston and the throw v attachment point on the rudder. Do you know the make of helm unit? It would help to know the volume of fluid pumped per turn of the wheel..
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Thanks for the advice. Looks like I'll need to do some measuring. How I do that is the tricky part. :p

As for the helm unit, they are hydraulic motors (there are two helms) driven by the wheels. The previous owner states these are RPMM50 obtained from Midlands Power and Motion. Does that help at all?

He also mentioned the rod ends are HMMS10. What does that mean?
 
Ok, looking at the Hynautic specs - the k-18 is 8.6 cu in and has 7" travel. Slightly less than three turns lock to lock, and probably slightly stiffer steering - ram would need to be attached to the rudder just fwd of current mounting.

The k-19 is 9 cu in, and has 9" travel. Slightly more than three turns and lighter steering - ram attached aft of current mounting position.
 
Hm, not a hydraulics expert, so not sure if they are generic part numbers or specific to midlands power and motion. Could be worth talking to them?

Ref my previous post, ignore the bit about the mounting positions on the rudder - just realised I made some massive assumptions about the rod lengths and piston areas of your current setup :)

Measure it up and see what fits.. Sorry!
 
rosssavage said:
Hm, not a hydraulics expert, so not sure if they are generic part numbers or specific to midlands power and motion. Could be worth talking to them?

Ref my previous post, ignore the bit about the mounting positions on the rudder - just realised I made some massive assumptions about the rod lengths and piston areas of your current setup :)

Measure it up and see what fits.. Sorry!
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All your advice is very much appreciated!

As I know people love it when they are provided information peace meal, I can offer the following information about the existing ram:
As per the previous owner's schematics, the ram is 35x20x250 travel, with 8.8 Cu In travel.
I'm not entirely sure what the 35x20 bit is, but the 250 I'm assuming is 250mm worth of travel in the piston. Which sounds about right. Of note, this is probably more than necessary and the rudders do go over more than they really need to.
 
Hi Cardo,
Sorry to hear of your trouble, we have very good courier deals set up for all of Europe, if you need anything collected from the UK and shipped out to you, just give me a shout.
Best of luck buddy.
 
SpottyDog5 said:
Hi Cardo,
Sorry to hear of your trouble, we have very good courier deals set up for all of Europe, if you need anything collected from the UK and shipped out to you, just give me a shout.
Best of luck buddy.
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SpottyDog, many thanks for the offer. The chap from the local boatyard who didn't seem massively confident hasn't turned up yet, so I may end up sorting this out myself (with some help to fit it later on), so I may well take you up on your offer.

I've been in touch with the supplier of the helm motors and they are actually EPMM50 units, which a quick Google search has informed me they have a 50cm3 displacement per revolution. This, again according to Google, is 3 Cu In.
Looking back at the rams that were linked by Ross, it would appear the K-19 unit is pretty much near perfect. The stroke is slightly less than what's currently fitted, but adjusting the location of the mount on the rudder bracket would sort this out nicely.
 
I am not terribly happy about any emergency steering system which relies on you having the bow thruster working - that predicates a decent battery and a running engine. The risk is too high.

And any contingency tiller plumbed into the hydraulics requires that the pump and pipes are unbreached - which may be the cause of you needing emergency steering anyway.

A direct mechanical linkage is required, capable of working either rudder on its own if needed.


When you have all the details worked out you will have a good reliable system by the look of all the tech advice.
 
Sorry to read of your problems. Hope you are able to get it sorted out soon ( and cheaply! ) and definately before you exit the canals into the Med.
 
sarabande said:
I am not terribly happy about any emergency steering system which relies on you having the bow thruster working - that predicates a decent battery and a running engine. The risk is too high.

And any contingency tiller plumbed into the hydraulics requires that the pump and pipes are unbreached - which may be the cause of you needing emergency steering anyway.

A direct mechanical linkage is required, capable of working either rudder on its own if needed.


When you have all the details worked out you will have a good reliable system by the look of all the tech advice.
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With the planned modifications to the steering system, I'm hoping to set it up so I will be able to mount a tiller that will in turn drive both or individual rudders (if a rudder is lost). This will not work through the hydraulics.

Pinnacle said:
Sorry to read of your problems. Hope you are able to get it sorted out soon ( and cheaply! ) and definately before you exit the canals into the Med.
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Thanks for the good wishes!

So, the chap from the local boatyard hasn't turned up as he said he would. Judging by the look he gave us yesterday, it wasn't looking massively promising.

Which means I'm going to see about sorting a lot of this myself. If I can, I want to order up the ram and then arrange to have a boatyard we will be passing fit it for me. This shouldn't be too difficult.

The next step is obtaining a new ram. The K-19 from this page http://www.hillarysboatshop.com.au/product.php?productid=296118&cat=2369&page=1 looks like the ticket. It's the right dimensions and travel and is built in aluminium and stainless, so should withstand some sea water splashing on it. Next question is how do I get hold of it?
 
Cardo said:
With the planned modifications to the steering system, I'm hoping to set it up so I will be able to mount a tiller that will in turn drive both or individual rudders (if a rudder is lost). This will not work through the hydraulics.



Thanks for the good wishes!

So, the chap from the local boatyard hasn't turned up as he said he would. Judging by the look he gave us yesterday, it wasn't looking massively promising.

Which means I'm going to see about sorting a lot of this myself. If I can, I want to order up the ram and then arrange to have a boatyard we will be passing fit it for me. This shouldn't be too difficult.

The next step is obtaining a new ram. The K-19 from this page http://www.hillarysboatshop.com.au/product.php?productid=296118&cat=2369&page=1 looks like the ticket. It's the right dimensions and travel and is built in aluminium and stainless, so should withstand some sea water splashing on it. Next question is how do I get hold of it?
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If it hasn't already been suggested try http://www.hypromarine.com/ for the K19 ram. I believe they are UK based rather than Australia.
 
Ok, so the local boatyard man came over and had a look. Whilst he seemed happy to do a straight replacement of the ram, he wasn't at all confident changing the steering system to the suggestions made above. Whilst he understood what I meant, once I'd drawn him a picture, he stated he wasn't able to do the calculations of where to mount the ram and he stated any tiny error could lead to catastrophic consequences.

He also stated it's not a good idea to have the ram pushing on the rudder from the side, as this can cause rudder failure. I'm not quite sure I follow this, as the pushing would be against the rudder bracket, which I believe is pretty solid. I don't see how this is different to the ram acting on a point on top of the rudder?

Thoughts?
 
Maybe he's thinking that if for some reason the rudder would not turn (dried out?) then the ram could break the rudder or pintle? If the ram was on top of the rudder maybe it would just break the pin. Not really sure I can see the difference.
 
Mount the ram on the top then, as per your current arrangement! :) On the side will be fine though.

Don't really need to do any calculating, rather measuring... Not sure what he's so scared of? Just make sure the ram stroke is slightly less than the rudder travel, and the ram will stop moving before it can over reach or damage the rudder.

Built my own hydraulic radar arch out of bits and pieces and trial and error. Seven yrs old and no problems.. (yet!)
 
rosssavage said:
Mount the ram on the top then, as per your current arrangement! :) On the side will be fine though.
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I'd prefer to mount it on the side as then it leaves the bar linking the rudders (and my template for decent emergency steering) in situ and I don't have to mess around with that.

Don't really need to do any calculating, rather measuring... Not sure what he's so scared of? Just make sure the ram stroke is slightly less than the rudder travel, and the ram will stop moving before it can over reach or damage the rudder.
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Well, this was my thinking. The rudders themselves can turn all the way to the side (perpendicular to boat) due to the way they're mounted. This is of course far more than necessary, so as long as the movement is less than that then I don't foresee a problem. To be honest, that K-19 ram looks just the ticket. The movement is equal to three turns of the wheel and the stroke is just less than what I have now (which is far too much anyway). Grehan has kindly provided me with a couple of names of people to speak to, so hopefully one of those will be able to assist.

Built my own hydraulic radar arch out of bits and pieces and trial and error. Seven yrs old and no problems.. (yet!)
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Don't say that, this steering system was going "well" for a number of years :p
 
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