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Loss of Rudder and Emergency Steering

Loss of Rudder and Emergency Steering

by Don Radcliffe » Sat Jan 20, 2007 2:05 pm

I got an email last week from friends who had Stella di Mare. They were aboard the Russian tanker who rescued them about 800 miles east of Antigua when they lost the rudder on their Grand Solei 39. After two days of trying to control the boat with various combinations of drogues and spinnaker poles, they gave up and hit the EPIRB when one of the drogue lines wrapped their prop.

This is the second boat I know of who was abandoned in about the same spot, just short of a circumnavigation, because they could not control the boat without the rudder. The other was First Light, a J46. There was also at least one ARC boat which is also floating around out there without a rudder this year, but both my friends were very experienced, and didn't give up without a fight. In fact, Stella di Mare lost their first rudder about 500 miles from Pago Pago and made it in under jury rig.

Without getting into a flame war about whether fin keel boats should be out there in the first place, can we have a discussion about how to successfully get one of these boats to track off the wind when the rudder is gone? The transpac and Pacific Cup require demonstrations of emergency steering, and the boats I have been on in those races have bit the bullet and had a separate, transom-hung rudder fabricated, but this is beyond the budget of most cruisers.

Any success stories?
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by Jack Tyler » Sat Jan 20, 2007 4:17 pm

Don, it's an excellent question and one about which I wish I saw a lot more discussed. To illustrate the barren nature of the topic, look at the massive list of standards for the construction and equipping of a liferaft in the ISAF Offshore Special Regs (many pages) and compare it with the paultry two statements in 4.15 about emergency steering.

In thinking about this for WHOOSH - beyond setting up blocks/tackles and welding on eyes to the emergency tiller, assuming we have to use that silly device and haven't lost the skeg-mounted rudder - the option that sounds to me most sensible when I hear it discussed is a properly fitted, separate rudder system, usually transom mounted and with the fittings installed permanently on the transom and only the rudder itself (and its tiller) to be mounted 'in extremis'.

One approach is illustrated by Hans new product at Scanmar. It's worth looking at because he talks through the issues in deploying the rudder and he offers several different mounting options. You'll find that at http://www.selfsteer.com/products/sos/index.php Don't miss the Latitude 38 letter at the bottom, which is hard to read but with some add'l interesting tidbits. He's trying to use a single design approach that will meet all needs in boats up to 50' so it represents more structure than may be necessary for many boats.

Another approach I've seen is transom-mounted hardware which in turn receives a daggerboard-type frame. The frame is left off the transom until a long passage is planned, at which point it is mounted above the waterline and is hinged. Should the rudder be lost, a replacement foil is slid down inside the daggerboard slot. Like Hans approach, it is controlled by a tiller...which may introduce its own set of issues given the force that may be required and the obstructions to the tiller's swing at the aft end of the cockpit.

This is not a simple issue to address, and I suspect a given 'solution' may shine in some applications and leave much to be desired in others.

Jack
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by henkmeuzelaar » Sat Jan 20, 2007 8:42 pm

As I have argued before, from a statistical point of view prevention of low-probability failure events, such as failure of a rig or rudder, is most effectively achieved through redundancy rather than by trying (in vain) to reduce the probability of failure to zero through improved quality and/or maintenance procedures.

As a Hunter Legend 43, Rivendel II's big spade rudder is likely to fail one day, in spite of regular maintenance and improved bearings. Therefore, Rivendel's windvane was selected to also be her spare (redundant) rudder.

Our "Autohelm" windvane, manufactured by Scanmar Marine (also producing the Monitor windvane and the Sayes Rig windvane) and not to be confused with the Autohelm brand of navigation instruments, contains a full-fledged, trim-tab controlled, accessory rudder http://www.terrawatch.net/Rivendelimages/RivRudders.jpg that is quite capable of steering the vessel in emergencies.

In fact, when sailing under windvane we have often kept the helm locked -- close to amidships -- for days on end, thereby greatly reducing wear and tear on our primary steering system and rudder.

Scanmar appears to have been so happy with the performance of the accessory Autohelm rudder that they now sell a very similar design as an emergency/spare rudder for offshore sailing vessels. (I assume that is what Jack was referring to).

One more detail: I have designed the transom attachment construction for the Autohelm as a breakaway bracket, to minimize the chance of losing both rudders to a collision with a log or container. The required breakaway force is supposed to be large enough to prevent the rudder from coming loose spontaneously in a seaway (the past 8 years have proven that part to work OK) but small enough to make it break loose without breaking the rudder itself or tearing up the transom. Let's hope that assumption never needs to be put to the test.....

Have fun

Flying Dutchman
Last edited by henkmeuzelaar on Sun Jan 21, 2007 10:59 am, edited 1 time in total.
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by Catamount » Sun Jan 21, 2007 10:11 am

I too agree that this is a topic in need of more discussion and prominence.

Certainly one should spend some time examining their steering system, getting to know how it works. Ultimately, you want to determine what the weak points are in the system, and how you might "beef "them up so they're no longer the weak points, or at least how you might repair them should they break.

I feel sorry for all you folks with those big expensive boats with wheel steering ;-) All that gearing, cables, sheaves, quadrants, shaft seals, bearings, etc... (or, heavens forbid, hydraulic pumps, hoses, pistons, etc...!) ;-)

My fin-keel, spade-rudder boat has tiller steering, with a direct connection between the (supposedly unbreakable) heavy-duty aluminum weldment tiller and a large diameter (3") heavy-wall stainless tube rudder shaft. In the boat, the rudder shaft is supported by a fiberglass tube that extends all the way from the hull to the deck, which appears to be lined with epoxy doped with graphite, making a full-length bearing.

There are a still a number of possible failure points, and I do carry a couple of spare parts (the bolt that connects the tiller to the tillerhead atop the ruddershaft, for example) for even this relatively simple system.

The worst case scenario would be actually loosing the rudder: either the bolt holding the tillerhead onto the ruddershaft shears and the whole rudder slips outs and goes to the bottom, or the rudder shaft itself shears (perhaps most lileky due to crevice corrosion of the shaft where it enters the rudder blade), and the rudder blade drops off...

So on to the redundant emergency rudder systems...

In addition to ScanMar's SOS Rudder system, Cape Horn is now also offering an emergency rudder system that works with their Wind Vane mounting system:

http://www.capehorn.com/sections/Safran ... nglais.htm

Some other references for and discussions of Emergency Rudder systems:

http://www.pacificcup.org/racetips/rudder.html

http://www.pineapplesails.com/articles/ ... /index.htm

http://www.sailinganarchy.com/forums/in ... opic=15793

http://www.sailinganarchy.com/forums/in ... opic=30896

I don't yet have this together, but I anticipate eventually adding the Cape Horn Wind Vane to my boat, and using their emergency rudder bearings for a cassette/daggerboard type emergency rudder system, similar to that shown here: http://www.pineapplesails.com/articles/ ... lg_pic.htm

Most of the references I've seen suggest that the emergency rudder blade needs to be at least 75% of the area of your original rudder in order to be effective. The rudder on my boat has an immersed area of 7.5 square feet, so my Emergency Rudder blade needs to be at least 5.6 square feet. If I assume that the total rudderblade dagger can't be any longer than 6' (so it can be stored in a berth), and that I want 18" or so in the cassette (so the bearings are well separated) that means my blade will have just over 4' of immersed depth and will have to be almost 16" wide. (As another consideration, you probably don't want your rudder to be deeper than the boat's draft).

Fun, fun, fun...

Regards,

Tim
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by Jack Tyler » Sun Jan 21, 2007 4:08 pm

Tim, for the sake of pushing the dialogue along a bit I'll suggest you could presume more design leeway than that 75% number you mentioned. First, the lever point (CE) of the improvised rudder is going to be aft, perhaps well aft, of the 'real' rudder. Second, depending on the design of the system, it may be possible to construct and use a semi-balanced blade (with its 'power steering' benefit). Third, the more area of the rudder in combination with its position further aft, the harder it will be for the crew to work it (unless it is semi-balanced, which most emergency rudders are not). Fourth, this presumably is a 'get home' rudder - boat speed can be kept down, one can fall back on one of the other tactics in heavy going (vs. punching ahead), and so I would think we each have some latitude in what will work under those circumstances.

Jack
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by Catamount » Sun Jan 21, 2007 5:28 pm

Hi Jack,

I can't remember where I came across that 75% figure -- I guess it was one of the Sailing Anarchy threads. So the context for that would be high-performance (race) boats with high-aspect fin keels, and spade rudders hung well aft. You raise a good point about the position of the emergency rudder relative to the standard rudder -- although in my case, the pivot for an emergency rudder would only be about 2.5 feet aft of the pivot point for my standard rudder.

Perhaps the farther your transom is from your standard rudder, and perhaps the longer your keel is, the smaller you might be able to get away with for an emergency rudder.

You also raise a good point about a balanced blade vs. an un-balanced one -- obviously it would be hard to make a balanced blade for a daggerblade/cassette system. As to the work required to "man" the tiller on these emergency rudder systems, on many of the ones I've seen the tiller is not handled directly (i.e. there's interference, such as with the backstay, that prevents the tiller from extending into the cockpit), rather the tiller is controlled by lines, which can have purchase systems or be led to winches in order to gain the advantage needed.

It would be interesting to get a good look at the Volvo and other round-the-world race boats, as the rules governing the design of those boats generally require that an emergency steering system be incorporated from the get-go (e.g., http://www.volvooceanrace.org/abouttherace/vo70rule/rule/). And, unfortunately, some of the boats have had experience using them!
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by leelocke » Mon Jan 22, 2007 12:06 am

We've opted for Hydrovane self-steering which also is a windvane with a full-fledged rudder. Mostly because we have a center cockpit and the Hydrovane simplifies installation. One of there marketing points is its use as emergency steering. The only thought I had about that is if the main rudder were lost due to collision (grounding, whale, container, etc.) we'd probably lose the Hydrovane rudder as well.
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by Paul L » Mon Jan 22, 2007 12:22 pm

The issue of emergency rudder size is not just the percentage of the original rudder, e.g. 75% or so, it is also the depth of the rudder. Hanging a temporary ruddder off the stern in what is probably rough seas means the stern will be doing some dancing in the air. I know of one boat who lost her rudder on a return from Hawaii. They mounted their emergency rudder and could not continue on course because it spent too much time out of the water airborne. To work on that boat, in those conditions, it needed to me a much deeper rudder.

These guys didn't actually loose the original rudder. The bearings came apart and the rudder post was slamming back and forth on the shaft so hard that they feared it would tear a hole in the boat. They decided to disconnect the rudder and push it out the shaft into the deep blue.

Paul L
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by Don Radcliffe » Mon Jan 22, 2007 3:57 pm

Thanks for the responses.

I looked at the scanmar SOS system, and their tilt-down system seems to look pretty good, but it's over $2,000, plus shipping and customs outside the US, requires some permanet mounting attachments on the back of the boat, and a place to stow the emergency rudder and bracket...

I also found a great article in sail-world "1400 miles without a rudder", which shows how Guenter Scholz rigged a spinnaker pole with a wooden blade as a rudder and used the staysail, main and poled out jib to balance a Contest 48 in varying conditions after the rudder post sheared off in this year's ARC. www.sail-world.com/news.cfm?Nid=29988

Their path wasn't very straight, but they made it.
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ER

by jentim » Mon Jan 22, 2007 9:17 pm

While sailing on a friend's 28' San Juan, the rudder broke off at the hull leaving the vessel rounding to wind. Our makeshift spinnaker pole / strapped paddle got us home-- with some fun and some “challenging” sail handling.

The point of this story is: I squashed a call for help, which might be included in this discussion, for the following reason: salvage.

I’m not a maritime attorney, except more and more information regarding salvage vs. towing heighten my awareness and further investigation. Of course, salvage costs may be more appropriate than losing one’s boat, yet insurance coverage may not help the uninformed.

Therefore, it seems prudent that skippers review what’s really important before an accident, and the resultant steps that are needed, as in safety, boat failure, insurance, etc.

Furthermore, I’ve since tried my emergency rudder, pretending my wheel was disabled. I’d hate to guide my boat for any real length of time this way.

Your thoughts welcomed.
Mike
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by henkmeuzelaar » Tue Jan 23, 2007 5:05 am

This is becoming an interesting thread. As described in my previous post, we do have the Scanmar Marine Autohelm windvane with accessory rudder. Because of several remarks about optimum or minimum backup rudder size, let me try to give an impression how this particular rudder works in practice, both with regard to it's main engineering parameters (size, weight, required steering force) and with regard to how well it keeps the vessel on course.

According to some sources, the Scanmar Autohelm rudder is currently the biggest accessory windvane rudder on the market. This is not hard to believe as it stands about 6 foot tall and weighs enough that only pretty strong persons can carry this rudder over their shoulder for any distance However, according to Scanmar, it's fully inserted, water-buoyed, weight is only 32 lbs or so. When we bought it nearly 10 years ago our plan was to make it removable so we would not permanently lose our swim platform. However, it is simply to heavy to move it around on a regular basis and it is also too difficult to find a good place to store it.

Finally, above 1 or 2 knots of boatspeed the force needed to swing the accessory rudder one way or another is quite sizeable. As pointed out by one of the other posters, these types of rudders tend not to be balanced much at all. Nonetheless, the trimtab, which controls the movement of the rudder, does a very good job and is itself very easy to move. Consequently, even the smallest electromechanical autopilot can easily control the accessory rudder. Provided the 12 ft long control cables connecting the windvane to the trimtab are properly tensioned our small Raymarine 10 (?) autopilot typically keeps the vessel on course to within 1 or 2 degrees when the wind dies and the seas are relatively calm.

The long and the short of it is that this Scanmar Autohelm accessory rudder has pretty much the maximum size and weight I would ever want to deal with for shorthanded cruising. Secondly, some of the images on the urls provided by Catamaount, e.g. showing the plywood box structure and/or showing rudders attached to what appear to be swimladder-like brackets, would not be strong enough to support a rudder this size. Consequently, the idea of accessory rudders with 75% of the primary rudder's size does not sound realistic to me.

Although it is true that Scanmar's accessory rudder windvane systems are quite expensive they instantly pay for themselves by obviating the need for expensive, power hungry hydraulic autopilots. Moereover, none of the parts is too complex to be replaceable by any handy person, thus keeping long-term maintenance and repair costs relatively low.

Assuming that the special breakaway bracket that I designed will indeed function properly in case we collide with a heavy floating object, the only remaining question is whether this accessory rudder is big enough to steer the vessel home. Although it may not look that big in comparison to the primary rudder, its strong positive effect on vessel tracking (e.g. in heave-to situations) suggests otherwise. Because it steers so easily now, even without very careful balancing of the sailplan, I expect it to still steer sufficiently well even though complete loss of the main rudder itself should result in significantly reduced tracking ability. Of course, it will become critical then to balance the sailplan VERY carefully.

Fair winds,

Flying Dutchman
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by Jack Tyler » Tue Jan 23, 2007 6:58 am

A couple of additional thoughts:

Scanmar offers 3 different 'emergency steering' approaches: Henk's Autohlem windvane (the aux rudder type). the SOS Rudder, and their M-Rud rudder 'sleeve', fitted over the servo oar on a Monitor.

Re: the M-Rud approach, the sleeve-type rudder is about 2x the size of the Monitor servo oar; that is not a very large foil. And to Paul's point, it's increase in size is more about depth than increased chord length.

The best (most sensitive, yet also powerful) windvane I've used is the original Sailomat 3040. It was also a aux rudder design; uniquely, it relied on a very small servo oar to control gearing which in turn controlled the position of the aux rudder. The gear box, gears and rudder were very strong. Like Henk's deep but short-chord rudder (on his Autohelm) and the M-Rud, the size of the 3040 aux rudder was quite small relative to the main rudder; perhaps 1/3 the size. As memory serves, the rudder was ~1m deep x .4m max chord length. It was a sophisticated NACA foil shape (moreso than the M-Rud and SOS products). We would routinely stow this on a shelf over a quarter berth; it weighed about 10 kg. As with all aux rudder windvanes, all of the steering force was transmitted to the transom, 'against' which the aux rudder had to steer - just as with the Autohelm and Hydrovane. The transom needs to be much stronger if using an aux rudder than what is required to mount a servo oar system. It I employed an emergency rudder system on WHOOSH, I would need to beef up the transom.

Some of the pineapple sails link photos in Tim's post are excellent; same with some of the real-world pics in the first of the sail anarchy links. (Thanks for all this, Tim). When reviewing these, here are some observations I'm left with:
1. It's more structurally challenging to build a lightweight, functional emergency rudder - and the attachment system - than it might seem. Pineapple's first cassette broke; it took GRP, big gudgeon straps and thru-bolts to hold it together. The Pac Cup rudder construction recommendation - essentially, a surfboard type structure - doesn't seem to offer sufficiently beefy attachment point. The Cape Horn product leaves me wondering about the wall thickness of the vertical tube and strength of the tiller. The 'weakest link' concept applies as we consider all these approaches.
2. Whatever is being used for the 'rudder' (floorboard, 'real' rudder, etc.) doesn't need to be very big tho' it does need to remain immersed. And the further aft the steering aid, the smaller it can be - e.g. when attaching something to a spin pole. One can adjust the area and balance of sails to aid in controlling the boat more, thereby needing less 'rudder surface'.
3. There are not just a 3 choices, but rather many different variations of 3 conceptual choices: drogue, pole and fitted rudder. Ingenuity abounds when you look at all the various ways others have tackled this problem. As just one example, one crew did the 'spin pole off the stern' approach, left off any flat board, and instead had pre-built a metal 'cross' that attached to the end of the pole. This elimated the pole's tendency to otherwise rotate, reduced the pole's loading and risk of bending, and the boat was still able to sail competitively with this arrangement...tho' they did have a racing crew aboard. As another example, while some claim the 'pole approach' won't work because the inboard end is too high and without sufficient leverage, others just rig steering lines from the aft end of the pole to each quarter (vs. try to control the front end of the pole).

Many, many ideas out there, it seems.

Jack
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by Catamount » Tue Jan 23, 2007 9:37 am

Another thought:

With the spin pole/steering oar concept using floorboards or bunkboards as the blade, one recommendation that I've heard, and which makes a lot of sense, is to pre-configure the attachment of the board to the pole with appropriate u-bolts or whatever. In otherwords, don't wait until you are out there and lose your rudder before trying to cobble together a steering oar with whatever bits you can scrounge up (I can imagine "borrowing" the extras of doubled hose clamps from the engine exhaust or cockpit drain plumbing, for example). Put the system together before you go, with dedicated hardware...

Regards,

Tim
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by hellosailor » Wed Jan 31, 2007 10:02 pm

Interesting thoughts. Has anyone considered installing gudgeons on the transom, and the matching pintles on some firm woodwork (settee back, etc.) so that it could be pulled and hung quickly, if needed as an emergency rudder? That would seem like a reasonably fast and inexpensive backup system, if the shape of the transom allowed for it. Still need to rig some steering lines and all...but the actual hardware should be an easy job if done while laid up instead of while bouncing around at sea.

??
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by idlerboat » Fri Feb 02, 2007 1:43 am

The use of existing pieces of your boat for emergency purposes is a good common sense aproach. Its amazing what you see when you look at your boat with those eyes. Bunk boards sudenly become window shutters, all you need is a long bolt and a strong back. Do it before you go and you will always know where it is! You will also know which one fits what window.
Smaller sections can be used as stop leaks or shoring...try it. Emergency storm boards, hatch covers.. the list is endless...all there for your use, as long as you have drilled one maybe two holes before you go.
The same aplies to emergency steering. If you look at what "materials " you have with unstressed eyes you will be able to design a resonably strong and effective steering system.
On shore where all you may need is to fabricate up a couple of small brackets or splice a line or two to get it working. Then try it:.. you can always wipe the water off the bits (or even re varnish the scratch marks) But once it is done the system stays with the boat. Fender boards can make great steering bits....or should l say steering bits can make great fender boards!!

cheers
Martin
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