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Old 02-02-2009, 07:20 AM   #1
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Just finished Hal Roth's 'Handling Storms'. Great read, very informative and surprisingly enough for such a subject, very encouraging.

Our large sea parachute anchor arrives soon and bridles for both it and our drogue are being manufactured. Hopefully they'll stay in their bags all the way to New Cal and back but somehow I doubt it - been some wild weather between Oz and New Cal so aint taking any chances.

Which leads me to our rudder.

We have a hefty rudder - glass over stainless framework supported by a large heel pintle. The through hole for our 70mm stainless rudder stock is massively glassed reinforced with solid bearings both top and bottom. Yesterday I removed the large tiller to discover a hairline fracture in the bronze fitting that attaches the wooden tiller to the head of the rudder stock. I'm now having a heavier S/S fitting made to replace it. The crack got me thinking.

As you can imagine, the rudder weighs a tonne and reading Hal's book along with many others to do with storm tactics, the stresses on the rudder blade, stock and bearings are tremendous when hanging off a parachute. They all recommend lashing the tiller amidships and using some form of rudder stops.

Now to me, lashing the tiller is all well and good. Even immobilising the rudder stock is great but when the vessel backs up in heavy seas, that rudder is going to want to twist, despite how immobilised everything else might be.

So here is a thought that I would appreciate some feedback on.

We lift Mico next week for the Blue Water survey, I'm seriously considering drilling a hole through the rudder body and through bolting large eyelets on either side (eyes parallel to the waterline).

By attaching chain or line to either side and bringing them back through the stern fairleads, we can then tie them off, effectively providing extra support to the rudder if we ever have to launch the parachute. The eyelets could also be used as an emergency tiller should the rudder head or timber tiller fail (although we also have a spare).

Anyone tried or seen this?

Fair winds,

Mico

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Old 02-02-2009, 09:01 AM   #2
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The arrangement you suggest is one which has been used on ships' lifeboats for a very long time. I think it safe therefore to assume that it works but ships' boats had their rudders hung outboard and they could be lifted of their rails when lying at a sea anchor. With a rudder hung the way yours is the advantages may be few as the weight of the rudder is not so important as the force exerted upon it by the sea. The weight will be a downward acting force (of course) whereas the force of the sea will be acting on a more horizontal plane. The chains or lines you describe could help support the weight of the rudder but that should not be an issue as the pintles and gudgeons should be well enough dimensioned to do that. They will not do a whole lot to counteract the twisting forces and could, perhaps, even be in the way and jam between the rodder top and the hull.

With your hull shape, I would rather beef up the skeg, putting a stainless steel shoe along the bottom. Then I would also beef up the lower bearing. If the new shoe could also be made to add addittional strangth to the bearing then even better.

Aye // Stephen
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Old 02-03-2009, 09:09 PM   #3
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The method you suggest is commonly used on boats with outboard tillers to limit rudder travel. However, often there are rudder stops inside the boat--depending on what type of steering one has--quadrant, etc, that do the same thing for a boat with inboard rudder stock as you have. You'll likely have the most success in limiting rudder travel with inboard stops. Any place you put your external stops will be highly loaded in a localized way whereas the inboard type can place the force on the rudder stock itself (if done with the types of collar/arm that one uses with an autopilot) which is designed to take the load.

Beware of cracks and loads--if you oversize your replacement fitting you're likely well and good, but SS is not very fatigue resistant at all so you should keep an eye on it. Also, depending upon age and previous use of the vessel and your access to qualified personnel, while the boat is out of the water, you may consider having the rudder stock, heel (gudgeon and pin) inspected by a qualified nondestructive testing (NDT) technician. If you don't know its history, and NDT is not a viable option, you should have a plan in place for how you can repair your rudder in the water, underway.

We were so serious about the above, that in addition to replacing the rudder blade (wood) which was clearly needed, we also replaced our 2-1/2" (64 mm) diameter x 10'5" long wrought bronze rudder stock and the gudgeon with in-kind new parts to ensure the structural integrity of our rudder system. Both stock and gudgeon were in what I thought was "ok to poor" condition due to corrosion but was told by the marine machine shop who has helped us with some projects that most sailors would have continued using them.

All offshore sailors should have a plan for emergency steering without the rudder as well. Losing a rudder is surprisingly common--so common that participants in the TransPac race must demonstrate to the race organizers what method they will employ when/if they lose the rudder.
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Old 02-04-2009, 07:22 AM   #4
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That's interesting you should mention the internal stops. About halfway down the rudder shaft, midway between the top and bottom bearings (the exposed rudder stock, accessable via the large lasserette (however you spell it) is a good 2m) is a large, 2 piece block of solid stainless with massive allan bolts holding it around the stock. The rudder stock is a single solid bar and I have no idea what purpose this large fitting has. It's just sitting there half way between both bearings.

I will post a pic of it tomorrow but I know that some Alajuela's had wheel steering and I was wondering if this was part of a quadrant that came as part of the original build? Its the size of a small plate about 3 inches deep - a pretty solid bit of whatever. Could this what you are referring to as an internal stop? Something that attaches to this?

Fair winds,

Mico
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Old 02-06-2009, 06:15 AM   #5
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. Could this what you are referring to as an internal stop? Something that attaches to this?

Fair winds,

Mico

[/quote]

Well it just goes to show what happens when you look a bit closer- going blind in me old age

Here are some pics of the 'large stainless block' halfway down our rudder post. Looking at them again it's now pretty obvious that its a join between two different sized shafts. Please correct me if it's something else.

I have no idea if this is part of the original design or a later modification - no records seem to exist. If it's part of the original design - why would you not continue the same sized rudder stock all the way from top to bottom?

Anyway - any suggestions of how we might create a rudder stop for this setup besides lashing the tiller?

Fair winds.

Mico

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Old 02-06-2009, 06:52 PM   #6
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Well it just goes to show what happens when you look a bit closer- going blind in me old age

Anyway - any suggestions of how we might create a rudder stop for this setup besides lashing the tiller?
Yea, that looks like what I've heard called a "muff" which allows you to connect two shafts together.

Right now, what limits the travel on your rudder? What hits what to stop things? In our case, we do not have rudder stops because our boat presently has a worm gear--it takes the loads from the rudder directly and forces on the rudder cannot move the helm.

What I was thinking about is a little arm that is typically is used for attaching a hydraulic piston/ram for an autopilot. It can be set up so that the arm literally hits a stop (bit of wood firmly attached to the hull, for example). I am sure there are other ways of doing this and you might be best getting the advice of someone local for it.

Here's a pic of one of the heavier duty types of arms that I'm talking about:

67448F_f.jpg

In your situation, you would likely want to put an arm of some sort onto the lower rudder stock in your pic. It doesn't have to be an arm for an autopilot, but would attach in the same way. If you plan to ever add an autopilot to your boat (other than an above deck tiller pilot for your tiller) then you'd likely be putting an arm similar to this (or two arms) for your autopilot system. Again, a local person with experience in steering systems and install of autopilots could be very helpful to you in this matter.

Fair winds,

Brenda
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Old 02-06-2009, 09:44 PM   #7
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A change of tack here because I reckon this debate is heading up the wrong channel.

First off I don't think you need rudder stops with tiller steering. With a wheel , esp with rod steering such as I have, you can just keep turning and turning the wheel and go way beyond the optimum 35* or thereabouts hard over position... The stops? well they stop you doing that. With a tiller you have visual indication of when you are hard over.

If you do go with stops you will need a stub tiller in the lazzaret (sp) similar to the one shown in the previous post... both it and the rudder stock will need to be keyed. The stops themselves would need to be very strongly attached to a plate which in turn would need to be very firmly attached to a shelf which would need to be very firmly attached to the boat.......

With the arrangement shown on Mico's boat I don't think you would ever be able to attach anything to that rudder itself which could reduce movement of the rudder to less than a few degrees which is what you would need. The angles of the effort are all up the creek. I would simply be lashing the tiller itself.... that way if simply hove to you can lash it up, down, whatever you want.

Thinking about the conditions that you would be lying to a parachute in... the boat isn't going to be going astern at a rate of knots... if it is your rudder is the least of your concerns.

I would be more inclined to worry about what I would be using as an emergency steering system if for whatever reason I lost main steering.....
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Old 02-07-2009, 07:37 PM   #8
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Going back to the original post, I am inclined to agree with Mico as I am thinking of doing the same on Escapade. It won't do any harm to fit the eyes and try them out at sea as an ounce of practical experience is worth a ton of speculation.

I remember reading somewhere that the old square rigged sailing ships had a hole drilled through the rudder at the top aft corner to allow tackles to be fitted in the event of a steering shaft failure that left the rudder attached.

Taking lines from eye bolts on the aft rudder tip up against the hull to cockpit winches may not totally immobilise the rudder when drifting astern against a parachute sea anchor, but they will reduce the loads on the rudder shaft and tiller or quadrant, which is Mico's aim. Its not a case of taking the vertical weight of the rudder as some seem to have interpreted the use of the ropes, but of reducing the turning forces on the rudder and steering gear as the vessel falls back.

Having observed fully developed F 9 to 10 seas in the North Sea from survey ships (and on one occasion F9 from a small sailing catamaran which cost me both rudders) my preference in extreme conditions is to head downwind rather than try to stand up to the punches, and carry a Jordan Series Drogue for that purpose. (But I also have thRee parachute anchors of different sizes inherited from the previous owners of two boats and kept for the proverbial lee shore situation - it seems they have a short working life when conditions get very serious) but thats another discussion . . .

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Old 02-07-2009, 10:05 PM   #9
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Hey, Frank, the emergency steering will be needed when the tiller gets yanked out of Mico's hands, goes hard over, and the rudder hits something its not supposed to, jamms, breaks, etc. I think you may be missing the point about rudder stops--one doesn't wish to have the tiller rammed into one's ribs in the middle of a heavy weather experience. With a tiller arrangement as Mico has--there is no steering gear--literally it is the tiller, the helmsman's body, and the tiller's attachment to the rudder stock (the bronze bit that cracked before...perhaps because of being lashed one too many times???) are the key parts.

One way of keeping the helmsman and his boat safe is the use of rudder stops--inboard stops or outboard chains/ropes. We all see different possibilities in the pic's shown by Mico. This project isn't rocket science nor is it difficult. I do believe Mico should talk to some local resources to design the (inboard) stops, though, if he doesn't have an engineering background or can't find an example to work by. Use of ropes, external, can prevent the total loss of the rudder if something big happens to the shaft...

Traditionally, folks with tillers often have to deal with rudders hung off the transom-and thus they end up using chains as rudder stops because they have no other choice. Mico is in a much better position to put in a couple inboard stops rather than the use of chains that will, almost with certainty, provide local damage to his fiberglass rudder. Mico's rudder, as I understand it, is fiberglass over a SS framework. It's not a big chunk of wood--it is an engineered system. It was designed with the rudder loading in mind but almost certainly not with point loading required by a chain/rope attachment. The traditional rudders which often had chains attached as rudder stops were made of wood... overbuilt and while they could be damaged by the localized loading, the behavior of wood in various structural applications including point loading is well understood and has been for centuries. Mico has a 70 mm rudder stock of SS. That's huge. I don't know the displacement of his boat, but I compare the scale to my 29T boat with its barn door rudder and 2.5" bronze rudder stock (64 mm) and think his stock can take anything he wishes to throw at it. Don't know about the rest of his systems.

Regarding emergency rudder--seriously, Mico, do come up with a well -reasoned way of steering in emergency. The muff you depict is a weakness in your system, IMHO, but might be nice when it comes time to replace or repair your rudder in the future. Have you given thought to emergency steering?

Looking forward to learning what you do for stops and how that all works out.

Warm regards,

Brenda and David
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Old 02-07-2009, 11:09 PM   #10
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Quote:
Regarding emergency rudder--seriously, Mico, do come up with a well -reasoned way of steering in emergency. The muff you depict is a weakness in your system, IMHO, but might be nice when it comes time to replace or repair your rudder in the future. Have you given thought to emergency steering?
Wow! Certainly a lot of ideas and views to consider - thank you all!

Perhaps I should spilt this into two sections.

This question first arose out of our purchase on a Tasman 15 Sea parachute anchor.

In all the varied literature and people we have spoken to, the chances of the yacht (under para anchor) 'backing' if the chute gives, can bring extensive pressure on the rudder if it is not secured and centered. The rudder in effect turns side on to sea as the yacht is pushed back.

We have a hefty windvane on the stern that is connected to the tiller by a very strong chain set up (see pic). In fact, we don't hand steer in anything over 12kts and use the chain most of the time. The tiller is just too heavy in a blow. We also have 2 x ST 1000 Raymarine autohelms which we use in winds 15kts and below. Any stronger and we immediately switch to the windvane.

Given that, I am very confident about us being able to really secure the tiller without any problem in the cockpit. We also have 2 spare tillers.

Logically following the path of potential failures from the tiller back; the next vulnerable point is the tiller and rudderpost connection and top bearing. There is going to be a lot of 'twist' pressure at this point. It's here that I found a small crack in the bronze fitting. That's now been rectified as I pulled the whole lot out and machined and fabricated a new fittings out of block stainless and 12mm stainless bar. (see pic).

The idea of the pad eyes on the rudder was to further assist inpreventing 'twist' under a parachute if the yacht 'backs'. I still think it has some merit.

It's the 'twist' I am more concerned about rather than the vertical motion.

All your comments about reinforcing the foot pintle are also very good and I have lined up to do just that when we lift, although we do have a pretty massive foot already - but hey - worth taking some extra care.

This then leaves me with that 'muff' midpost. I've had an engineer just look at it and I have been told that we'd loose the back of the stern before that gave way but again, it does have some vulnerability to 'twist' - hence again, the idea of the pad eyes.

I agree with all the comments for the need to prevent the rudder being accidently 'slammed over'. At present, full rudder comes to rest against a half channel in the stern so I am still thinking that through. Although, as I mentioned - we always sail with the chain setup so I am less concerned for the potential for injury in the cockpit.

Emergency Steering?

Good point.

Our windvane is our obvious first choice for emergency steering. I guess it depends on the circumstances. If we loose the tiller and the top bearing connection but the rudder is still intact - then those pad eyes could come in very handy.

If we loose the rudder completely than I have one bloody big hole to patch but saying that, the windvane should be able to substitute.

I have crewed on a yacht that had the rudder snapped completely off and we jury rigged steering by lashing the spiniker pole across the stern and using a drogue on a bridle around both winches. Coupled with some adjustment to the sail plan - this did get us back safely although it was absolute crap for steering us back into the pen We now carry a drogue and all the bridles just in case.

Again, thanks heaps for sharing your ideas with us

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Old 02-08-2009, 08:39 AM   #11
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OK... having looked again at all the pics.... I reckon the weakness in that whole rudder asembly lies from the muff northwards and if I was putting a stub tiller and stops it would be fitted below the muff. Mine isn't anything fancy and anyone with welding skills could put it together... unfortunately no pics to hand... hardest bit would be the keyway.

But that is only going to limit the rudder to 35*/35* not secure the rudder amidships and if you are backing up you really do need that tiller secured with minimum slop...not 5* either way. Only way you are really going to secure that amidships or anywhere else is by lashing the tiller....however...

I don't really like the look of how the tiller is attached to the rudder post...looks like just one bolt and a few inches of overlap... I'd be scrapping that and fitting a steel tiller or using a fitting with a long ( maybe 8 inch or so) overlap. I'd also be opening up that muff to see what really is inside there...

Cheers

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Old 02-08-2009, 08:47 AM   #12
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Quote:
I don't really like the look of how the tiller is attached to the rudder post...looks like just one bolt and a few inches of overlap... I'd be scrapping that and fitting a steel tiller or using a fitting with a long ( maybe 8 inch or so) overlap. I'd also be opening up that muff to see what really is inside there...

Cheers. Frank
Sorry - the pic is a bit deceptive. The timber stock actually goes right through under the top stainless plate and butts up against a vertical plate and is though bolted to that also. I just had to chisel about 12mm off the top to fit the rest under the plate. The top plate helps form a tight slot for the tiller to fit into and we then have the two through bolts on the extended arm.
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Old 02-08-2009, 09:37 AM   #13
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Sorry - the pic is a bit deceptive. The timber stock actually goes right through under the top stainless plate and butts up against a vertical plate and is though bolted to that also. I just had to chisel about 12mm off the top to fit the rest under the plate. The top plate helps form a tight slot for the tiller to fit into and we then have the two through bolts on the extended arm.
Ah so....that sounds better...
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Old 02-09-2009, 12:51 AM   #14
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Hi, Mico!

I'm glad to hear that you have not one but 2 autohelms to assist plus the wind steerer! That makes me much happier for your situation.

The muff is mainly an issue because you don't really know what's going on under it and it's not much of an overlap. Further--a muff like this can be an unkeyed connection between the upper and lower part. You can put a keyed flange connecting the two parts (that would have been better). If your autopilot arm was attached below the muff, you'd be better off, of course.

I bet you have many other things to take care of rather than dealing with the musings of us folks here on CL! Good luck in taking care of all before you set off!
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