Emergency tiller

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Graham_Wright

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www.mastaclimba.com
I've just dropped my rudder (into a pit, on the hard) to repair some chips and refit the seals. It is an opportunity to tackle the fitting of an emergency tiller. As a centre cockpit boat, the tiller has to pass over the stern cabin so the rudder post needs extending vertically through the cabin deckhead.

Can anyone advise what wall thickness an diameter tube would be adequate for this please? The rudder post is 1 1/2" in diameter and is filled with a squared top. Attachment is not a problem.

I can provide a bearing at cabin deckhead level so bending probably isn't an issue but what about the torsion?

Can't do that sum!
 
Graham_Wright said:
I've just dropped my rudder (into a pit, on the hard) to repair some chips and refit the seals. It is an opportunity to tackle the fitting of an emergency tiller. As a centre cockpit boat, the tiller has to pass over the stern cabin so the rudder post needs extending vertically through the cabin deckhead.

Can anyone advise what wall thickness an diameter tube would be adequate for this please? The rudder post is 1 1/2" in diameter and is filled with a squared top. Attachment is not a problem.

I can provide a bearing at cabin deckhead level so bending probably isn't an issue but what about the torsion?

Can't do that sum!
Click to expand...

I have an emergency tiller but it is well under powered, in heavy weather it would need lanyard lines to control it.
Far better is the on board autohelm 6000, i used that when the steering cable clamps let go
 
I imagine your steering gear is under a bed in the stern cabin. I imagine that your rudder post would have to be extended by about 1.5 metres to emerge through the cabin top. Yes a bearing at the cabin top would be best. I would think a tube of appropriate size to fit the rudder post ie about 1.5 inches with a tiller clamped to the top would suffice. Use the heaviest walled thickness you can find. Sorry no idea on actual loads except the existing rudder tube might indicate size needed.
I would be inclined to mount the top bearing under the cabin roof with a thin GRP membrane over the hole to keep water out. Smash through the membrane if you need emergency steering. Or perhaps the bearing mounted on top with a membrane inside under the cabin roof. Sorry not much help in fact olewill waffling. good luck
 
What you need is a tube with a square slot in the bottom that does not extend beyond the walls of the tube so that you can pass it through the bearings ... and the bearings are a close fit.

What is the size of the square end? How high is the tiller above the cabin top?
 
William_H said:
I imagine your steering gear is under a bed in the stern cabin. I imagine that your rudder post would have to be extended by about 1.5 metres to emerge through the cabin top. Yes a bearing at the cabin top would be best. I would think a tube of appropriate size to fit the rudder post ie about 1.5 inches with a tiller clamped to the top would suffice. Use the heaviest walled thickness you can find. Sorry no idea on actual loads except the existing rudder tube might indicate size needed.
I would be inclined to mount the top bearing under the cabin roof with a thin GRP membrane over the hole to keep water out. Smash through the membrane if you need emergency steering. Or perhaps the bearing mounted on top with a membrane inside under the cabin roof. Sorry not much help in fact olewill waffling. good luck
Click to expand...

This is a self build and access to the steering gear (arranged to be ) simple. It is easy to disconnect the autopilot and almost as easy to disconnect the wires to the quadrant. The rudder post is 1 1/2" in diameter, the tube 50mm ID (sealed with O rings). The height to the cabin top is around 40". The idea is to instal a "proper" bearing at the top (interesting because of the compound angles) with a "proper" plug in SS.

The secondary use of this arrangement is to help lower the rudder with a line through this hole to the rudder post which is conveniently tapped (3/8" UNF for some strange reason!). The rudder is a heavy old lump and a line through the an eye bolt in this hole to a winch (maybe by a turning block) would confer control.

The emergency tiller will probably be the spinnaker pole. I can achieve five foot lever with that (sticking out sternwards as well) so the forr'ard end clears the wheel or as much as you like if I remove the wheel.

The thickest wall tube with an OD 1 1/2" would be solid bar! However, I would like the secondary (or rather primary) purpose for this to be the ensign staff thus my quest for the lightest acceptable.

Waffle away William;- your posts are always well accepted!
 
TradewindSailor said:
What you need is a tube with a square slot in the bottom that does not extend beyond the walls of the tube so that you can pass it through the bearings ... and the bearings are a close fit.

What is the size of the square end? How high is the tiller above the cabin top?
Click to expand...

The bearings are below the squared end and I can arrange a coupling to link the square with whatever tube extends upwards.

My reply to William answers the other points.
 
FWIW I have a Pentland Centre Cockpit & the rudder post ends with a square section top between the bunks in the aft cabin. The L-shaped metal tiller simply has a square socket that drops over the top, It has to be operated while standing inside the aft cabin & does not need to poke thro the cabin top - it would be tricky to keep such an arrangement water tight.
 
sailorman said:
Due to my on board autohelm i was able to re attach the wires whilst it steered in a sea way. This would not have been possible with a helmsman steering
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If your autohelm ram is still working, as in your case, why not simply try using this first to steer, rather than using your emergency tiller which needs tackle to control it? Often, again as in your case, its a problem with the wires, these breaking or detaching from the steering quadrant. The ram is independant of this wire system & should still allow steerage.
 
alant said:
If your autohelm ram is still working, as in your case, why not simply try using this first to steer, rather than using your emergency tiller which needs tackle to control it? Often, again as in your case, its a problem with the wires, these breaking or detaching from the steering quadrant. The ram is independant of this wire system & should still allow steerage.
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I did
the thought of the emergency tiller was never a consideration. The quadrant was steady enough even with a sea running to re thread the wires & tension them
 
The Rival 41C has a deck flange and cap similar in style to a water/diesel filler. This is located on the aft cabin roof directly above the rudder stock. I'll be down at the boat on Thursday and will take pictures and measurements and report back.

Regards,

BlowingOldBoots
 
For what it's worth, on our Maxi 34 the rudder stock passes up through the aft cabin to the deck on a full-time basis. There's a bearing and seal under the bunk, together with the quadrant, and then another bearing (and presumably a light rain/spray seal) in the deck. The separation of the two bearings makes it a reassuringly strong structure - you'd need a lot of extra bulk to do it with just the foot or so of height under the bunk.

The emergency tiller just bolts onto the protruding end on deck, after removing a little white GRP hat.

The stock is from memory about 1-1/2", and I think it's solid bar.

Pete
 
Searush said:
it would be tricky to keep such an arrangement water tight.
Click to expand...

In an "emergency", watertight is perhaps unimportant. When not required, closing should be simple enough.

As nobody has answered my original question, I will experiment with some MS tubing. If I attach/weld an arm on one the end representative of the length of the tiller I could deploy, secure the other to prevent rotation and measure the twist, that should answer it.
 
My emergency tiller, comes up through the aft deck, using an old fuel filler (Pre water/diesel/petrol), just with a square in the cover. It's a 2" filler. Inside is a nylon 66 black bearing, to reduce to the 40mm tube of the emergency tiller. The tiller itself is squared to fit the top of the rudder shaft. The pipe rudder is bent at 90 degrees above deck and over the aft cabin. It has a permanent wooden extension and landyards led forward to the cockpit.
 
My emergency rudder tiller shaft is made from 2 inch nominal bore sched 40 stainless pipe with a square hole fabricated at the end to fit over the square on the top end of my rubber shaft.

I have an aft cabin bit my rudder does not pass through the rear cabin but I do have a fitting like a fuel/water filler such that a threaded coller on the emergency rudder shaft that will screw into the filler type arrangement on the aft deck. The tiller fits into a yoke fitting on the top of the emergency rudder shaft like a standard tiller arrangement but is easy removable with a drop nose pin.
 
My emergency steering, on a 36ft ketch, consists of a vertical alloy tube of about 1.75" OD, which is two parts, for easy stowage. The bottom end has a short 1.5" box section, which fits over the square on the rudder stock. The top section has a "Tee Piece", into which another length of the same size alloy tube fits, as a tiller. The tiller is about 3ft long. The tiller faces aft, which makes steering a slightly strange business. There is, as others have said, a plastic fitting with a screwed plug, like a deck filler, into which the vertical tube ships, and the fitting acts as the top bearing. I have used it once, from necessity.
 
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