Hi All - I’m trying to order the autopilot tiller arm for my NS30 (for connecting my undermount Raymarine EV-200 Sail) and the options for the arm require a through-bolt through the rudder post. I had assumed that it was solid, given the various tapers of the post and the square head at the top. Drilling through a solid stainless steel 1.75" dia. bar, curled up down in the locker, does not seem feasible.
Does anyone else have this done? The tech at Edson seems to think that the steering quadrant also has a pin through the rudder post, which I can’t see in my photos.
Thoughts? Knowledge? Experience?
Thanks
Bob Gehrman
NS30U #396 “Quickbeam”
Baltimore, Maryland
I don’t recall how I came by them, but attached are three factory drawings bearing on the rudder and shaft design. They’re not on Nonsuch.org, but I’ll fix that.
Two are for 26s, but the third (“rudder drawing 4”) is for 30’s. It seems to indicate that the shaft is “Sandvick 63/40 hollow round bar, type 316 stainless steel, 2.48” O.D. x 1.57" I.D."
IF this is correct, AND if your shaft meets that spec, the good news is that it is hollow, and the bad news is you have to drill through 1/4" of stainless – twice.
I took a closer look at the drawing after I hit the button. My previous message gave the spec for the rudder stock within which the rudder shaft rotates.
The rudder shaft is shown spec’d as 1-3/4" round bar type 304 stainless steel. It’s uppermost 1.5" are machined to a 1" square. Two inches below that are machined to a 1.5" round, and five inches below that are machined to 1.625" round.
I guess that drilling in place is the only choice. It won’t be easy but I suggest that a jig could be made to guide the drill pretty easily by a welder and it would pay for itself. I’m thinking of a bolt together split collar with a drill guide pipe section welded to it at exactly 90 degrees to the tangent face of the shaft. Drilling round stainless accurately is a challenge even in a drill press. Good bits, lots of cutting oil, start small and increase size. On that note the guide might have a bushing to drill the start hole.
Just spit balling really … maybe it’s a place to start.
The drawing for the 30 rudder shaft indicates a 1/4x1/4 keyway. In my 33 I believe that the radial drive wheel is keyed to the shaft. I think that the bronze tiller arm, shaft mounted just above the radial drive wheel, is also keyed to the same keyway. Further, based on the picture of a 10”bronze tiller arm on the Edson website (see link), I do not see how you would drill a hole through the tiller arm to effect attachment to the rudder shaft.
The Edson tiller arms are custom machined to fit your rudder shaft. That machining can include a keyway to match that of the rudder shaft.
Edson does shown quadrants that require through
bolting. A quadrant is not what you want for the autopilot.
I installed an Edson autopilot tiller arm on Toyger in 2015. I just saw your posting and pulled the Edson data sheet I used for ordering the autopilot arm and key. Toyger is a 1987 N30U #422 so I think our rudder stocks are identical. When I ordered the tiller arm from Edson the information I provided on the Edson Autopilot Tiller Arm Data Sheet is as follows:
Bore size is 2.375”
Specify: “Key”.
Keyway size: is 0.25” x. 0.25”
Length of Arm: 10”
In the ‘Sketch Location of Tiller Arm’ I sketched the Tiller Arm facing ‘AFT’ with the Autopilot mounted to the Starboard side.
In the Diagram ‘Mark the Location of the Keyway’ I modified the diagram showing the Keyway is located on the forward face of the rudder stock, indicated the the arm is facing AFT and indicated the open side of the arm is on the opposite side of the one provided in the diagram.(would be starboard on my boat)
The Edson part numbers I ordered for Edson were: 926-10-610-MKII (Tiller Arm) with the bore & key as specified and 946-400 (Machining Charge - Special Key)
The parts that Edson provided fit perfectly.
These are custom machined parts so please verify that the info I used for Toyger is also correct for Quickbeam before ordering.
My tiller arm is attached to a Simrad HLD350 drive unit mounted to a support which is glassed to the hull and starboard transom.
I use a B&G Zeus System to control the Autopilot.
I hope the information I provided is of use to you.
If you want I can scan the Edson Data Sheet and attach that later.
I agree with Paul. I have machined 316 stainless steel and would be hesitant in trying to drill it in place with a hand drill unless it is absolutely necessary. If you stop pushing hard, even for a second, the material in front of the drill bit will work harden and it’s game over. Practicing on a piece of 316 stainless steel, available at any metal supply store, would give you a feel for the work and the pushing force required. Drill bits from an industrial supply store, while expensive, are a lot better quality than the variable quality ones from a hardware store.
I like the Edson arm arrangement if you have a key slot available.
Great help All! I’m going to stop back over at the boat and see if the keyway is there at the quadrant. Might have to reconsider my planned layout for the linear drive.
Keyway found! I guess I’ll have to plan on lowering the drive unit now similar to John Barbour’s. There’s no way I could get a 3/8" hole in 304 stainless bar down in the hole.
John - do you have any pics of your drive unit mounting?
Bob Gehrman
NS30U #396 “Quickbeam”
Baltimore, Maryland
Glad you found the key way Bob. Drilling with anything other than a drill press and very good alignment jig would be iffy at best and extremely difficult.
When I bought my NS22 “Moustaches”, in 2012, it arrived with a recently-installed Lewmar Cobra rack and pinion wheel steering system. I promptly removed all of that and went back to what I love, a good old tiller. I sold the system and someone got a heck of a good deal. The Lewmar “tiller arm” (that was attached to the rudder post) had required that a hole be drilled into the post for a holding pin. The folks who had installed the system (Northshore Boatworks in Bronte, Ontario) did a gorgeous job. I am sure that they dropped the rudder right out of the boat to work on it (easy as there was no quadrant, etc.). But, yes, I can see the need for very careful work and jigs, a drill press, etc. in order to do this properly. Not a job for any hand drill, I’d say.
Attaching photos of my belowdeck autopilot installation.
Please bear in mind that the photos were taken during a 2 year refit so some things are not ship-shape.
The 1st photo will show the keyway on the rudder shaft.
The keyway faces forward but I rotated the shaft so I could get a photo of the keyway.
I’m not sure how many photos I can send them in one posting.
If need be I’ll send a second posting.
Good luck on your installation.
You’ll be glad you did it.
Cheers!
