Autohelm on a canoe stern

stacer said:
Looks like it although mine has a small cabin unlike my last, a Character Boats Whammel which was an open boat. Although an AH isn’t essential, sailing here around the islands of the Firth of Clyde can be quite cold and wet even in the summer and the ability to go below for a few minutes to make coffee or just for shelter would be welcome.View attachment 144213
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Nice.. just sitting headroom? Looks quite a lot heavier than mine. 70kg without the rig. & 15ft LOA. Bit warmer about here:)
 
DownWest said:
Nice.. just sitting headroom? Looks quite a lot heavier than mine. 70kg without the rig. & 15ft LOA. Bit warmer about here:)
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2 bunks (very cosy?) and just sitting headroom, there is a a small detachable galley with a single burner stove. Mine is a lot heavier at around 500kg, rig won’t add much, standing lug loose footed main and small jib. Heading into winter now and not much sailing until the spring.
 
If it is possible to fit on the rudder head a short "tiller arm" at square angles with the tiller, the Autohelm actuator would be alined fore and aft and and would not protrude at all sideways.
 
Sandro said:
If it is possible to fit on the rudder head a short "tiller arm" at square angles with the tiller, the Autohelm actuator would be alined fore and aft and and would not protrude at all sideways.
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I've seen that done on a boat many years ago .... it works.

But the only problem I see is that the extra arm needs to be sufficient length to accommodate the stroke of the AH rod as well as sweep It may be on such as OP's boat restricted ?
 
Last edited:
Refueler said:
I've seen that done on a boat many years ago .... it works.

But the only problem I see is that the extra arm needs to be sufficient length to accommodate the stroke of the AH rod as well as sweep It may be on such as OP's boat restricted ?
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I mentioned that in #16, but I can't remember the recommended distance for the pin from the rudder axis. It might be a bit long.
 
If the autohelm is not at near right angles to the tiller in mid position you lose capacity- geometrical mathematics indicate the proportion. May not be important in light airs and responsive boat but really an issue in heavy weather on a boat needing tiller to be fairly hard over to make the right course
 
oldmanofthehills said:
If the autohelm is not at near right angles to the tiller in mid position you lose capacity- geometrical mathematics indicate the proportion. May not be important in light airs and responsive boat but really an issue in heavy weather on a boat needing tiller to be fairly hard over to make the right course
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Only if it is attached directly to the tiller. Please see the sketch in previous post.
 
Buck Turgidson said:
View attachment 144207

The geometry for a and b is the same. B allows the tiller pilot to be mounted at an angle to reduce width.
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So as I understand from your doodle .... R is a second arm or bracket ....
This now clears up the 'missing bit' ....

Thank you for finally agreeing with my continued insistence on AH needs to be at 90 deg to steering arm whether it be an offset arm, bracket or the tiller,
 
DownWest said:
Set your AH to it's middle position, then put the non actuator end just inside the gunnel (don't fancy it projecting over the side, might get wet..) swing it so the end of the rod is about the recommended distance from the rudder pivot axis and at right angles to the line from the end of the rod to the axis (imagine your tiller in that position) then make up the tiller bracket to to mount it at that position.
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i've quoted this post again ... as now - 'Buck' having kindly doodled ... it is now clear what is suggested.

As they say - a picture is worth a 1000 words.

As I have been 'banging on' about and it appears others AND 'Buck / DW' agree - the important part is to habe that 90 degrees to the operating line.

OK ... just one strange item though .. and you can check this with pencil / protractor / paper ... if you set AH at right angles to the tiller when midships and then fit a bracket that allows pin to locate ... the arc that is made when AH operates is acceptable - there is a difference of steps - but not significant enough. But if you connect pin on tiller and move other end of AH forward or back offsetting that angle - the you get a problem as I illiustrated in my sketch earlier.
 
Refueler said:
So as I understand from your doodle .... R is a second arm or bracket ....
This now clears up the 'missing bit' ....

Thank you for finally agreeing with my continued insistence on AH needs to be at 90 deg to steering arm whether it be an offset arm, bracket or the tiller,
Click to expand...
R is the distance from the center of rotation. Known as a radius. The picture shows that mounting the autohelm at The tangent to radius R has the same effect at point a and point b. To achieve the connection at point b you could mount a bracket to the tiller or a second arm from the hub. Frequently a quadrant is fitted around a rudder stock to attach autopilot servos. In all cases for the angular displacement to be equal in both directions the actuator needs to be mounted at the tangent to the arc. In my example you can see that b is NOT at 90deg to the tiller.
 
Refueler said:
So as I understand from your doodle .... R is a second arm or bracket ....
This now clears up the 'missing bit' ....

Thank you for finally agreeing with my continued insistence on AH needs to be at 90 deg to steering arm whether it be an offset arm, bracket or the tiller,
Click to expand...
??????. You need to go back and edit all the posts where you insisted it had to be 90 to the tiller.
 
Buck Turgidson said:
R is the distance from the center of rotation. Known as a radius. The picture shows that mounting the autohelm at The tangent to radius R has the same effect at point a and point b. To achieve the connection at point b you could mount a bracket to the tiller or a second arm from the hub. Frequently a quadrant is fitted around a rudder stock to attach autopilot servos. In all cases for the angular displacement to be equal in both directions the actuator needs to be mounted at the tangent to the arc. In my example you can see that b is NOT at 90deg to the tiller.
Click to expand...
\

There is NO argument about being 90 to ;steering arm' ...............

The guy wanted to fit his AH1000 to his tiller - without having the outboard end hanging over side ... that was answered simply before all this tit tat ...

Blimey - talk about blinkers !!

Bye Bye ...
 
Refueler said:
The angle created by a bracket off the tiller to the rudder stock makes no difference to the steering arc ...

Why ? Because the main point is to keep the AH at right angles to the tiller at midships. Whether the pin is on the tiller or xx inches to the side ... is not an issue ...

If you move the AH forward and its not at right angles to the tiller at midships .... then the rate of change of tiller / rudder per unit of AH rod change alters significantly whether rod extending or retracting.
Click to expand...
For those who don’t want to read it all, this is the post which caused the debate.
 
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