Status Check - 8 Sept 02 Rudder question

[Ed Harrow]

Hot one today, 90ishF outside, don't know what it was inside Our Lady...

Anyway, got some chain to tie the last pair of stands together, and moved the forward pair forward (back from a Zach break - thankfully the kittens are gone...)

I've started work on rudder removal, as I think I mentioned. The head/hub, whatever one calls it, at the top of the rudder post, to which the tiller attaches has to come off. I did a bit of surgery today, and turned up two headless allen bolts (another brain fart, can't think what they are called). They came out fine, but (and the picture didn't come out very good) there appears to be a bit of round stuff, probably bronze, maybe 3/8 - 1/2" in diameter going into the thing radially. It does not appear to go all the way through. It got to hot to continue on this mission, but it is not at all clear to me what that piece is about. Is it safe to assume this hub/head is keyed to the rudder post? Thoughts on the round bit going into it? Should I try a slide hammer to yank the hub/head off? (If there's a proper name for this thing somebody please pass it along.

Pictures are getting closer, but we're not there yet - too much going on.

[Concordia..41]

I have heard it called the rudder head, tiller head, tiller fitting, tiller coupling and tiller connector. Tiller connector was used mostly on Hobbie Cats. I’ve always know it to be the rudder head. In the specifications for Sarah - Tiller: Locust with bronze rudder head companion fitting, chrome plated.

Hedderwick: Marine Architecture (1830)
PART III - PRACTICE OF SHIPBUILDING.
Steering Apparatus. — First, the Tiller. — This is a lever of wood or iron, as found most convenient; it is fixed at one end into the head of the rudder, and at the other end the power is applied for steering the vessel. Its length from the rudder-head should be about four times the breadth of the rudder; its thickness at the fore part of the mortise, the twartship way, about 5-11ths, or one half the siding dimension of the rudder-head, and its depth at the same place one a half times its breadth. In lining out this piece, it is generally kept about 3-4ths of an inch broader than the mortise the thwartship way at the rudder-head, and tapered from that to the end or tiller-head, to 1-3d of the breadth and depth added together. Thus suppose the breadth 5 inches, and depth 7 inches; then the 5 + 7 = 12, and 1-3d of 12 is 4 inches for the diameter of the head. The length of the tiller from the rudder-head to the end is divided into three equal parts; that next the rudder is left dquare; the middle division has the corners taken off in form of an octagon, and from that to the head is made round. The head is left about half an inch thicker, and paned up like a diamond, or carved to fancy.

It is found by experience, that a good steering vessel of 200 tons, having a rudder of 3 feet broad, and tiller of 12 feet (making a power of 4 to 1 with the extremity of the rudder), may be steered by one man without the assistance of any other power, when the weather is moderate. However, in strong winds the power must be increased. In vessels which have not a steering wheel, this is frequently done by fixing a block to the end of the tiller, and another to at the rail or side of the ship; a rope is then rove through these blocks, one end being made fast at the rail, and the other held in the hands of the man steering; the power is thus doubled, being 8 to 1.

Various methods of increasing the power for steering are adopted. Most vessels under 300 tons are steered with the tiller and tiller-ropes, as above mentioned. Larger vessels are commonly steered by a power produced with the wheel and axle. The wheel is called the Steering Wheel. It is erected on the deck a little before the tiller. It is also sometimes fitted abaft the rudder-head, or where found most convenient. The wheel is made similar to any common coach-wheel, only having the addition of hand-knobs or spokes on the outside of the rim, to lay hold of by the hands in turning it round. The wheel stands vertically, being fixed on a horizontal iron spindle (it must be copper, if near the compass), on which is also fixed a drum or barrel. The wheels vary in dimensions from 3½ to 5 feet in diameter over the extremity of the hand-knobs; the drum or barrel on which the tiller ropes are wound, is from 1-5th to 1-4th the extreme diameter of the wheel. The wheel-ropes are made fast to the end of the tiller, and pass through sheves [sic] or blocks fixed to the side rail of the vessel opposite the tiller-head, then to the barrel of the wheel, so that by turning the wheel either way, the tiller will move accordingly.

In the case of the tiller being of the common length, i.e. as long as to produce a power of three to one with the breadth of the rudder, the wheel rope is brought immediately from the tiller to the barrel of the vessel, having only the sheves or blocks at the rail to conduct the rope fair to the barrel. Suppose the breadth of the rudder of a ship of 300 tons to be 3½ feet, the length of the tiller 11 feet, making, by the tiller alone, a power of 3 to 1; that the tiller-rope is taken to the barrel of a wheel whose power is 4 to 1; then a power of 4 to 1, acting upon a power of 3 to 1, produces a total power of 12 to 1, as compared with the extreme breadth of the rudder; and with this, one man will be able to steer any common vessel of about this size. But for ships of 400 or 500 tons, the power must be made equal to about 18 or 20 to 1, to be steered in the same manner, with the common tiller and wheel, by one man only.

When the vessel is to be steered with a tiller abaft the rudder-head, which in this case must be very short (in many vessels it cannot be allowed longer than the breadth of the rudder), a great increase of power of the wheel, or by tackles from each side to the tiller and wheel, either by the one or other of these, or by both, is required. It is most frequently done by fixing a purchase of 2 or 3 to 1 on the end of the short tiller, and reducing the diameter of the barrel, to give the wheel more power over the barrel.

There are many other methods which might be employed for augmenting the power, as by wheels and pinions, &c. Whatever method may be employed, the power must always be adequate to steer the vessel by one or two men.

The wheel is considered to be of great advantage, not only in giving more power, but also in enabling the helmsman to steer the vessel nearer her true course. Mostly all vessels are fitted with steering wheels, even some of our one-masted vessels, such as smacks, have them, although it is considered to be a little more in the way of the main-sheet than the common tiller.

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Peter Hedderwick: A Treatise on Marine Architecture, containing the theory and practice of shipbuilding, with rules for the proportions of masts, rigging, weight of anchors, &c including Practical Geometry and the Principles of Mechanics; observations on the Strength of Materials, Hydrostatics, &c. with many valuable tables calculated for the use of shipwrights and seamen; also the proportions, scantlings, construction, and propelling power of steam-ships. Illustrated with twenty large plates, containing plans and draughts of merchant-vessels from fifty to five hundred tons, with mast and rigging plans; plans and sections of a steam-boat of eighty-horse power; and eight quarto plates of diagrams, &c., by Peter Hedderwick.
Printed for the Author, Edinburgh, 1830. pp 323-324.
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Transcribed by Lars.Bruzelius@udac.se
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The Maritime History Virtual Archives | Shipbuilding.
© Copyright 2000 Lars Bruzelius. 

Dave

Sun over the foreyard.

[Concordia..41]

Three guesses who couldn't sleep last night :rolleyes:

- Margo

[Wild Dingo]

And I thought I had a bad case of insomnia!! tongue.gif

Hey Ed... hows the little tacker going? give him a hug from us all mate!

Take it easy
Shane

sigh... pictureless again... sigh :(

[Bob Cleek]

Hi Ed! Trying to figure out how stuff comes apart can be a challenge, that's for sure. Sounds like you are on to it. Let me urge you to hold off on the "bigger hammer" solution until you are really certain how it is put together. Chances are it comes apart pretty easily. You wouldn't want to start whacking it with a slide hammer or whatever, only to find out you'd just bent a couple of fastenings or pins or whatever, which then will never come out! LOL Do you know anybody with a boat from the same yard that might have a similar fitting and has already encountered the solution? Just a thought.

[RGM]

Given the nature, purpose and location of the assembly in the vessel it wouldn't have been the "Hammer and Tong" squad that put that fine thing together. As Bob indicates, hold off on any of the heavy handed methods until you've thoroughly explored all other disassembly options. I'ld be looking for a cross pin perhaps that hopefully can be driven or drilled out. Good luck, and put that slide hammer away would ya please?

[Ed Harrow]

One phrase that was drilled into me as a kid was "Don't force it". I've sent pictures along to several, for the others:

1. There is a keyway
2. Neither set screw bears any relationship to the key, and I have no way of knowing if they are original, either.
3. Rodger mentions a cross pin. There is that bit of round stock I mentioned in my original post. As near as I've found thus far, it does not go all the way thru. I'll take a bit of paper to the opposite side and clean it up, just to double check. Dave suggested drilling that bit of round and using an easyout to see if it might be a threaded bolt that was then cut off.
Would a cross pin typically be used in addition to a key?

Would this level of detail be specified by the designer, or would this typically be left to the builder to decide?

[Paul Scheuer]

Any marks on the pin that might suggest that it was driven in ? If it went in tight, it would probably have some "hoof prints" on the end. Or there might be some marks that would indicate that is was sawn off, or broken off. How 'bout someone posting the pics.

[RGM]

A cross pin wouldn't have to go all the way thru. I like Dave's idea of using an easy-out on the thing first to see if in a previous life it was actually bolt or similar animal. The key ties the tiller head to the rudder stock in a rotational fashion. A cross pin would keep the whole thing from coming apart in the vertical direction. Two wonderful design elements working together, isn't that nice? I like Paul's description of "hoof prints", I'm going to start using that phrase, thanks Paul. Good luck Ed.

[ 09-12-2002, 01:45 PM: Message edited by: RGM ]

[Ed Harrow]

OK, using a bit of 400 grit I now know that the camera doesn't lie, and what looked like the other end of the pin is, in fact, I guess, the other end of the pin (or perhaps an additional pin...).

It goes in at about 5 O'clock and exits at 12. There are no substantial marks on this pin to indicate that it was driven in.

So the head is held in place with 1 key, 1 cross pin, and two setscrews! They didn't want it to go anywhere.

Ideas as to why the pin might be installed other than across the diameter of the rudder post? I'm thinking that, given the angle, the set screws might tend to "wedge" it into place? I'm going to first attempt some gentle taps upon the end of it using a bit of aluminum stock and see what happens.

[RGM]

Oh ye of many hammers. Time out. I think that you would be happier if you first tried to use a modified C-clamp to push/squeeze it out, or at least get it to move. Fab a "bridge" type of device out of angle iron or whatever else you've got laying around that will allow you set the foot of your C-clamp above but still centered over the far end of the pin(s). Fab a slug or spacer of some sort to fit between the business end of your clamp and the pin. The slug will have a smaller diameter than the pin. Line all of this stuff up, give it big a squeeze, tap the handle end of the clamp with your favorite hammer if you must and see what happens. Good luck.

[Ed Harrow]

Hmmmm, I think I have a C clamp type device that might just be perfect.

Now isn't it better to have many hammers so one can pick the one that's just right for the job, rather than use a 5 pounder for everything, LOL.

[Ed Harrow]

OK, so I got it off. It was not the way I expected it to be, however.

First I used the valve-spring compressor for my Norton, in conjunction with a 9/32 1/4"-drive socket, to push the ~1/2" bit of round stock mentioned above. (actually first I measured that on both sides of the rudder-post head to ensure it wasn't tapered smile.gif )

When I noted the thing had been displaced inward some, I checked the other side. No difference! It was pretty obvious that the one had nothing to do with the other. I presumed at that point that there was nothing keeping it from coming off, and there wasn't.

There was a key in the keyway, and an interesting one it is, too. It is not purely rectangular, but more dog-leg shaped, with two shoulders off opposite sides, one on the ID, the other on the OD, so to speak. This might simply be from wear, I'll need to check that tomorrow.

[brian.cunningham]

Did you ever see VASA's setup.
a pole coming down from the deck goes through a pivot and connects to a tiller!

SWIFTWOOD, like any kayak with a rudder, get's steered with my feet :D Now I just need to figure out how to connect the two rudders out on the outriggers.

[ 09-16-2002, 12:06 AM: Message edited by: brian.cunningham ]

[RGM]

Congradulations Ed. Valve spring compressor for a Norton motorcycle, not bad, not bad at all. Do you still have the Norton? Sounds like you've got a stepped key. Basically one key machined to fit two different sized key ways. Sometimes that is easier to do than broach a new key way on an item such as your rudder stock that would match the key way on the tiller head coupling. Is the key way on the coupling slightly larger than the one on the rudder stock?Potentially there's alot of monkey business and expense to get the rudder stock out of the boat,into a machine shop then back again for broaching a new keyway as opposed to leaving it in the boat and just making a stepped key. So, maybe that's what you are looking at instead of wear and tear. Were you able to remove the coupling without too much brutality?

[Ed Harrow]

Like somebody said about something, it just gets curiouser and curiouser. The round bit coming in from the back side of the tiller head is right at the top of the keyway. The bit that I pushed in had a mating similar hole that had been filled with braze (I'm guessing) material. One of the two setscrew holes is so close to the previous ones that the threads from the one intersect with the threads from the other. Also, quite a number of small holes drilled into the rudder post around one of the set screws.

Yes, I still have the Norton. When it was right it was so very, very right. However after a bit one came to understand what happened to British industry...

The rudder-post head came off with a lot less effort than some previous party put in to getting it off...

[Rich VanValkenburg]

Sounds like the 'braze' material might have been what's left of the pin when it sheared off? Sound possible? Set screws wouldn't have been strong enough to hold the tillerhead position. email me a picture if you can.

Rich

[Ed Harrow]

Nope, nuthin sheared off. The pin didn't pass thru the rudder post. I will send you a picture or two.

Thought I was about to get the site updated this weekend, but ran into one more situation I didn't understand. How I ever posted the page in the first place is beyond me...