Why couldn't we turn to Starboard?

[sfellows]

We have Whitlock-type rod (Mamba) steering and an autopilot drive linked directly to it via a clutch and interlocking cogs directly underneath the pedestal.

Sailing under autopilot last week we noticed a “click” each time the autopilot changed direction (e.g. turn to port and back to starboard) and the auto-pilot seemed to struggle in gusts.

However the bigger issue was when we arrived into Weymouth from Dartmouth hand-steering now after sailing the inshore passage at Portland Bill.

On trying to turn the rudder to Starboard we had very little rudder (almost none), but good steerage to port, and so we had very little manoeuvrability. Turning to port and back to starboard had no effect. The wheel/rudder jammed at exactly same place with a small turn to starboard. This caused some concern, and whilst we tried to sort ourselves out and see what we could do I did a hard to port full rudder to come around 270 degrees into the wind. Once this was completed I returned the rudder to centre with the wheel and then tried to starboard. It was completely free and we had full rudder to port and starboard again. (Phew!)

Anyhow, the question for the experts is:

Was this likely to be something caught around the rudder?

Or does it sound as though it could be the drive on the autopilot or a rod steering issue?

(During the process of trying to sort it out we did turn the auto-pilot on to see if it allowed a bigger turn to starboard (it didn’t) and so we then turned it off again. Once turned off the starboard turn was still jammed and was only fixed by the full wheel/rudder over to port.

 

[Supertramp]

We have Whitlock-type rod (Mamba) steering and an autopilot drive linked directly to it via a clutch and interlocking cogs directly underneath the pedestal.

Sailing under autopilot last week we noticed a “click” each time the autopilot changed direction (e.g. turn to port and back to starboard) and the auto-pilot seemed to struggle in gusts.

However the bigger issue was when we arrived into Weymouth from Dartmouth hand-steering now after sailing the inshore passage at Portland Bill.

On trying to turn the rudder to Starboard we had very little rudder (almost none), but good steerage to port, and so we had very little manoeuvrability. Turning to port and back to starboard had no effect. The wheel/rudder jammed at exactly same place with a small turn to starboard. This caused some concern, and whilst we tried to sort ourselves out and see what we could do I did a hard to port full rudder to come around 270 degrees into the wind. Once this was completed I returned the rudder to centre with the wheel and then tried to starboard. It was completely free and we had full rudder to port and starboard again. (Phew!)

Anyhow, the question for the experts is:

Was this likely to be something caught around the rudder?

Or does it sound as though it could be the drive on the autopilot or a rod steering issue?

(During the process of trying to sort it out we did turn the auto-pilot on to see if it allowed a bigger turn to starboard (it didn’t) and so we then turned it off again. Once turned off the starboard turn was still jammed and was only fixed by the full wheel/rudder over to port.

I have the same system but with bulkhead mounted wheels and Mamba autopilot. Thankfully no problem like you describe. Having just gone over the system and had replaced a bevel box and some UJ's I have some insight. The shafts, UJ's and bevel boxes all rotate several times lock to lock so unlikely to fail as you describe. The autopilot engages or disengages via its clutch (ie on or off). I would check the rudder head area where I would expect a quadrant and a reduction gearbox (that turns 2 rotations of the shafts into a 45 degree arc and links to the quadrant. On my boat these are seriously sized bits of kit. Check the angles over the range of travel and for any play that could allow a linkage to lock up. Take care not to mess up the rudder angle indicator for the autopilot. If nothing amiss then I would be looking for rudder fouling.

 

[Eeyore]

I had almost the same thing happen on my boat about 12 months ago. Turning into a small 'duck pond' anchorage, the steering completely failed - the previous day under autopilot I could hear an intermittent click like yours. Investigation revealed the vertical shaft which goes down the pedestal has a splined connection to the first bevel gearbox under the pedestal. The splines had worn away allowing the wheel to spin without actually doing anything, the clicking was the last stand of the splines before giving up. I completely stripped all the gearboxes, replaced bearings, torque rods, tie rod ends etc.