Chain tension-steering system

[Ian_Edwards]

I've just been checking over the steering gear.
The boat has twin wheels and an autopilot.
The port wheel has a heavy chain driving a cog, which is meshed into a quadrant mounted on the rudder shaft, it's a bit like a quarter of a differential.
The starboard wheel is the same and the two quadrants are connected by a massive tie bar.
The port wheel is also connected to a Lewmar Manba type 2 rotary drive, so the rotary drive moves the wheel which the moves the rudders.
There are 3 chains, each about 1m long, and they are all quite slack, if you move one wheel, you need to move it by about 5 degrees before the other wheel moves.
The chains needs to be tightened and each one has a bottle screw (turnbuckel?), so it's easy to do.
Questions, how tight should the chains be?
Is there a rule of thumb?
I'd like to get rid of the slack, but don't want to make it too tight and cause excessive wear.

 

[RichardS]

My chains are also quite slack but I have only one wheel so don't notice any problem.

When I got the boat mine were adjusted such that in the middle of the chain run it is possible to squeeze the up and down runs together so that they just touch each other and I've always adjusted it back to that position after doing any work.

Richard

 

[pvb]

I think the answer is to tighten it until it feels about right - that's not very scientific I'm afraid. I have twin wheels with chain drives connected to cables, and I actually reduced the tension from the factory setting, because it didn't feel right.

 

[Major_Clanger]

I can't quite picture your set-up, but the last thing you want to happen is for a chain to come off its quadrant. It happened to be once in the middle of Biscay in December. The wire came off the quadrant in a nasty slop and I had to sit in a stinky lazerette trying to put it back without it taking my fingers off every time a sea hit the rudders.

Tighten the chains uniformly so they there's only slight play in both planes, and then systematically check for tight spots at all points from hard over one way to t'other. Obviously give a little ease on the bottlescrew when this happens and all should be fine.

 

[rogerthebodger]

As these chains are not transmitting any significant power/ force just tighten the chains until all the free play has been removed and check again after a few sails.

 

[Stemar]

I think that if you remove all the slack, you'll be loading everything way too much. Chains generally run with a bit of slack and, up to the point where there's risk of the chain coming adrift, the slacker, the less load, but too loose and the steering will be sloppy. I rather think pvb has it right