Hydraulic steering

[claymore]

My 30ft Long Keeled Motorsailer has hydraulic steering. I've noticed that from time to time, having reversed off a pontoon, there's a minor struggle to get the steering to respond when I apply the other lock. I've narrowed this down to a few causes and wondered whether anyone else has had a similar experience. I'm thinking either I have an airlock, there is a insufficient pressure from the ram - say if it undersized, or the geometry - the way it aligns with the rudder is wrong. It all works fine going forward, perhaps there is a little play but generally OK. The pressure on the rudderblade generated by 6 or 7 tons of boat travelling backwards must be quite something and it seems that if the blade is allowed to go too far over, the resulting increased surface area presented must result in a greater force needed to bring it back to centre or onto the other lock. So where do I start? Answers on a postcard please!!

<P ID="edit"><FONT SIZE=-1>Edited by claymore on Mon Sep 10 14:35:04 2001 (server time).</FONT></P>

 

[ccscott49]

I had a similar problem, I thought it was air in the system, which could cause the fault. But I needed a new steering hydraulic pump, how old is yours? Check for air first, you can normally hear it, as the valves chatter especially going astern and you get lock-ups, after that its a hydraulic steering specialist. That is if everything mechanical is ok!

 

[gus]

You may well have air in your system and that can make the steering heavy but not just part of the time. If you fix up a clear sealed tube to the filler/breather of your steering head and permanently attach a bottle half full of fluid, you can see at a glance if there is air and top up in a trice without any messing about.
Does your rudder have stops? If not it may be getting forced over till it jams and thus hard to straighten. It may be going to far over, which will diminish the leverage that the ram has on the rudder arm. Is the rudder arm too short to give effective leverage? Are you applying any ahead thrust with your prop to help straighten the rudder against the reverse flow? It may also be possible that the steering head has a small leak past the valves and is not able to give you the pressure required to control the steering under strenuous conditions.

 

[claymore]

Thanks for that Gus
The boat is in Kilmelford and they agree with you on rudder stops
cheers