Mounting tiller pilot closer than recommended to pivot point on tiller.

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fredrussell

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On my boat, in boisterous conditions, the tiller pilot (ST2000) sometimes reacts to gusts to slowly. It doesn’t matter how ‘quickly’ you set it to react, it can never do so as fast as a person. If memory serves, Raymarine recommend mounting tiller pilot pin 14” from the pivot point. The way I see it, the closer pin is to pivot, the faster the TP will steer boat, albeit using more power to do so. My boat is light on the tiller, and I’m fairly sure the TP will manage the extra effort - I’m just wondering if anyone has experimented with this?
 
I had a play but TBH a tiller pilot is not and never will be as responsive as a person. We can feel the wind and see what is coming. A TP has to wait for the boat to change direction, then react. OTOH my windvane is actually a better helm than I am. Not only is it response to wind changes, often before they affect the boat, but it doesn't get tired or distracted.
 
I’m mainly trying to improve the reaction time, but I suppose another benefit is that the steering range, as in max port to max starboard before ram reaches end of travel, is increased. I shall experiment and report back.
 
You won't improve reaction time, you'll just make the steering more jerky because it will steer more for a given movement, but still probably too late.
 
Try it ! You can always move it back again ?
I mounted hydraulic as per calculations and ended up with 8.5 turns lock to lock..
Decided to experiment and halved the distance. Was perfect reducing to 3.5 turns which turned out to be the perfect amount for the autopilot and still effortless to turn the wheel
 
A rough guide to whether it's going to do damage would be to compare the max size boat your TP is rated for and then pro rate yours. For ever % smaller your boat you can move the pin back the same amount. I did say rough.
 
anoccasionalyachtsman said:
A rough guide to whether it's going to do damage would be to compare the max size boat your TP is rated for and then pro rate yours. For ever % smaller your boat you can move the pin back the same amount. I did say rough.
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ST2000 good for up to 4.5t displacement. My boat is 3 tonnes, and very light helm so doubt I’ll be stressing it too much. Nice easy project to make a temp mount for TP with numerous positions on it for a bit of trial and error. Like I say, I’ll write it up when I try it.
 
lustyd said:
You won't improve reaction time, you'll just make the steering more jerky because it will steer more for a given movement, but still probably too late.
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Reaction time is not the phrase I should have used - obviously that remains the same wherever you mount the TP. It’s more that once boat has been knocked off course by a gust, by the time the TP has corrected the boat has gone too far off course for the limited travel of the TP to remedy. It maxes out. I’m interested to see if a greater range of TP tiller movement might help in that situation.
I have been reading with great envy the current thread on below deck autopilots. Lucky blighters.
 
The autopilot with a separate ram are quicker and stronger. Mine is closer than the instructions suggest and works well, but it is possible to de-sensitise it when motoring on the flat for example. Can you do that with the 2000?

Worth trying, in my experience.
 
Just thank your lucky stars you don't have my old Vivacity, standing on the side deck would be enough to throw the tiller pilot off its game :) I think it's worth a go but you may be up against the motor speed. I'll be interested to hear what happens my guess is either no change or the boat steers wildly back and forth
 
fredrussell said:
I have been reading with great envy the current thread on below deck autopilots. Lucky blighters.
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With hydraulic wheel steering a hydraulic auto pilot is the dogs danglys, cant hear a thing and works better than a person on a boat that has great directional stabilty.. Lack of a balanced boat could be the op,s problem ?
The helm does not rotate with hydraulic but you can spin the wheel forever.. So i took my friend and her 5 yr old out. Had autopilot on through the harbour mouth and we purposly say away from the wheel. (remote control ;) ) and her 5 yr old stood behind the wheel randomly turning it..
You should have seen the look of horror from other boats as they thought a small kid who couldnt even see was steering... haha..
 
Rappey said:
With hydraulic wheel steering a hydraulic auto pilot is the dogs danglys, cant hear a thing and works better than a person on a boat that has great directional stabilty.. Lack of a balanced boat could be the op,s problem ?
The helm does not rotate with hydraulic but you can spin the wheel forever.. So i took my friend and her 5 yr old out. Had autopilot on through the harbour mouth and we purposly say away from the wheel. (remote control ;) ) and her 5 yr old stood behind the wheel randomly turning it..
You should have seen the look of horror from other boats as they thought a small kid who couldn't even see was steering... haha..
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Good point about the balance of the boat. My windvane requires a well balanced sail plan. I tend to be less fussy when on the tiller pilot.
 
fredrussell said:
Reaction time is not the phrase I should have used - obviously that remains the same wherever you mount the TP. It’s more that once boat has been knocked off course by a gust, by the time the TP has corrected the boat has gone too far off course for the limited travel of the TP to remedy. It maxes out. I’m interested to see if a greater range of TP tiller movement might help in that situation.
I have been reading with great envy the current thread on below deck autopilots. Lucky blighters.
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I believe that by moving the drive closer to the rudder's pivot you will indeed improve the reaction time, in the sense that the rate of helm change per second will be greater. Also the maximum degree of helm will increase. What you will lose is force on the rudder, which may well be acceptable in your case.
 
fredrussell said:
ST2000 good for up to 4.5t displacement. My boat is 3 tonnes, and very light helm so doubt I’ll be stressing it too much. Nice easy project to make a temp mount for TP with numerous positions on it for a bit of trial and error. Like I say, I’ll write it up when I try it.
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Your bare boat will be 3 tonnes but with sails, running rigging, water, diesel, gas, crockery, inflatable, outboard, personal gear and not forgetting the crew weight. This will be ¾ to 1 tonne. Still within the ST2000 limit, but getting close. My Fulmar is supposed to weigh 4½ tonnes, but measures 5½ tonnes when lifted.

Moving the pin may help a bit but as mentioned before, but any electronic autopilot will never respond as fast as a helmsman. Ensuring the helm is in line with the centreline will also reduce the effort on the tiller.
 
If you move the pin you will mess up the geometry and it won't work properly. The ST 2000 gives two critical dimensions: the distance from the centre of the rudder stock to the pin and the distance from the pin to the pivot point of the Tiller Pilot. The angle between those two dimensions must be 90 degrees.
 
fredrussell said:
If memory serves, Raymarine recommend mounting tiller pilot pin 14” from the pivot point.
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The pin should be 18" (not 14") from the rudder pivot point, measured perpendicular to the axis of the rudder pivot.

tillergirl said:
The ST 2000 gives two critical dimensions: the distance from the centre of the rudder stock to the pin and the distance from the pin to the pivot point of the Tiller Pilot. The angle between those two dimensions must be 90 degrees.
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The 18" from the rudder pivot point must be measured perpendicular to the axis of the rudder pivot point. This may well be different from the distance between the centre of the rudder stock and the pin. For example, if the angle between the rudder pivot axis and the tiller is not 90 degrees - e.g. the rudder's shaft or transom mounting is not vertical; or the rudder axis is vertical, but tiller is not horizontal - or, alternatively, the centre of the rudder stock is not the axis of pivot (e.g. as with traditional transom hung rudder), then the directly measured length will be greater or smaller than 18" (even though the two dimensions mentioned are at 90 degrees to one another)

Linky to ST2000 Manual (Install instructions p32): ST1000 & ST2000 Tiller Pilots | Raymarine
 
When you say your boat is light on the helm is that because it takes very little input to hold a course and has very little weather helm or it has a balanced/ over balanced rudder so you can put in large movements and it doesn't feel heavy? If the latter then if you could be sailing with badly balanced sails making it hard for the autopilot as it has to do a lot of work. You wouldn't notice as you can move quickly and the steering still feels light.
 
I have a similar problem on Jissel under sail. It's very difficult - nigh on impossible to get the sails balanced so she doesn't need constant correction. It isn't so much the time it takes for the tiller pilot to start reacting, it's the time it takes to move the tiller to where the rudder's doing some good once it starts.

As I see it, the ideal is for the TP to be at right angles to the tiller when straight ahead, but that's negotiable up to a point - the TP will soon learn where straight ahead is. The important thing is that it shouldn't be over-stressed, and it should be at full travel before the tiller gets to the stops, port and starboard. The rest - measurements and so on don't matter too much.

I'd have a play with a temporary lash-up and see how it goes. If it works, it's time to start drilling holes, if not, no harm done.

Pro tip: If the tiller pilot's playing silly wotsits as you move around, take the magnetised penknife out of your pocket! It took me most a season to figure that one out!
 
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