Monitor Windvane

Monitor Windvane

M•RUD—Monitor Emergency Rudder

Our challenge was to be able to convert the Monitor aboard a 50 foot BOC boat, in the roaring forties, into a true emergency rudder. We knew that the strength required for survival in these conditions would guarantee a more than adequate back up system for cruisers having the misfortune to lose their boat’s rudder. M•RUD has been designed to meet the following criteria:

M•RUD offers a unique solution to a serious problem. Download MRUD Brochure

In Heavy Weather Sailing, by Adlard Coles the author remarks, "Breakages of rudders are almost as common as breakages of masts." The Monitor has survived the toughest oceans in the world, sailed through seas and weather which would qualify as a cruiser’s nightmare and kept on steering.

The BOC is unparalleled as a test of equipment. The BOC boats not only round Cape Horn, they stay in the Southern Ocean lower latitudes for several months of brutal weather and towering seas. M•RUD was developed with these conditions in mind.

The M•RUD Conversion Kit

Finally, a solution to the nightmare of losing your boat’s main rudder.

Many attempts have been made to make individual emergency rudders. The majority require very expensive custom engineering and manufacturing. Excessive weight and size make these custom rudders difficult to store and install at sea, and, even so most have questionable performance and reliability.

The beauty of the Monitor M•RUD system is that it uses the regular Monitor servopendulum system which is converted to an emergency rudder. The standard Monitor mounting system is extremely strong because it has four stainless steel mounting tubes that are spread apart to distribute the load over a larger area. If the mounting tubes are long, diagonal tubes are added for additional strength

Half the emergency rudder problem is the method of attachment. With the Monitor in place the attachment system is already there! The Monitor mounting system is strong enough to support a large, rigid rudder.

The Monitor M•RUD is highly efficient because it has a high lift NACA profile and because it is located behind the boat. The size of the emergency rudder can therefore be smaller making it more practical to store and to mount, yet still large enough to steer a 50 foot boat.

The Monitor principle works on the boat’s own rudder rather than using an auxiliary rudder/trimtab system like our own auto-helm windvane. Such systems can be used as emergency rudders, but they are not in general the best principle for normal self steering.

If a boat experiences weather that is bad enough to break the boat’s main rudder those conditions are probably bad enough to do severe damage to an auxiliary rudder type of self steering. The damaged main rudder can also damage the auxiliary rudder. The servopendulum gear does not have this problem. It has the ability to move to the side, out of the way, and it has an easily replaced safety tube in case of an overload situation.

We prefer to use the best principle for normal self steering, (servopendulum) and in the unlikely situation that the boat’s own rudder is broken, the strong, stainless steel M•RUD can be mounted at sea and steer the boat to safety. You can steer by hand by moving the counterweight from left to right, by using the regular Monitor airvane or by hooking up a small inexpensive autopilot to the Monitor counterweight.

A pin with a cotter ring holds the servo paddle which is removed and replaced by the much larger emergency rudder assembly. The stainless steel rudder is foam filled for strength and flotation. The hinge has a special tapered hinge pin to make it easier to mount at sea. The pendulum is locked and supported by a wedge between the pendulum and the strutguard. Spectra lines add extra support for front and side loads, just the way a mast is stayed.

The M•RUD is similar to your life raft. We hope that you never have to use it, but if you do it will be the most important piece of gear on board.

Can you afford to be without it?

A boat without a rudder is a serious matter and these instructions are intended to make sure that your M•RUD is understood and used properly in the event of rudder failure on your boat.

We strongly recommend that you fit M•RUD to your Monitor before you leave on your next long cruise and even use it on a short test sail. Should the installation become necessary, you may be in rough seas. If you practice putting M•RUD on in port, it will be much easier to repeat the installation later at sea.

Your M•RUD assembly contains:

When you transform the Monitor to a much larger, rigged emergency rudder the loads are greatly increased and you should make sure that your Monitor is mounted as follows:

Backing Plates

The Monitor mounting brackets do not normally need backing plates. If your boat is a light weight core construction you might need them. If in doubt consult the factory.


Since 1991 all Monitor units built have strutguards. This protective “bumper” goes behind the pendulum and connects the legs of the main frame with each other. It also makes the main frame a lot stronger. Older Monitors did not have the strutguard but it can be retrofitted. With the use of M•RUD the Monitor has to have a strutguard because this is where the wedge that holds and supports the pendulum is placed.

Test the fit of the wedge

Place the wedge between the strutguard and the pendulum. There might be some variation in the fabrication and location of the strutguard. Lock the wedge in place with the supplied crossbolts or locking pins.

Through bolt Clamp Tubes (only on old Monitors)

The lower mounting tubes are attached to the frame with clamp tubes that are attached to the bottom of the frame legs. To be absolutely sure that the tubes cannot escape from the clamp tube both fittings should be through bolted with small stainless steel bolts (included).


The Monitor frame is attached to the hull in four places. With longer mounting tubes we sometimes add same side diagonal tubes which make the installation tremendously strong. With the use of M•RUD some installations should add diagonals. Consult the Monitor factory for advice.

The entire M•RUD assembly is stored in a safety colored orange bag marked "Emergency Rudder."

Mounting and operation of the M•RUD at sea

Heave to with the boat and try to avoid forward movement. Wear your safety harness.

Your Monitor now has a very rigid and strong spade rudder ready to steer your boat. Of course you need to balance your boat carefully and possibly reduce sails somewhat. Compared to your boat’s rudder you may feel that the M•RUD is too small to control your boat. However, we have purposely kept it this way (will not break, easy to store, easier to install, etc.). With a normal boat there are very small corrections with the rudder unless you carry too much sail or have ignored balancing the sail plan. The large size of the boat’s main rudder is necessary for maneuverability which is needed when you dock the boat or are on a race course. With M•RUD in the open ocean and a course to steer you can make slow corrections. At your destination you can anchor or get help for the last few miles if you feel that you cannot maneuver in tight corners.

Three methods of steering

Quote from email received from Andrew Wilkes, February 2005:
"In 2003-2004 we sailed from the UK, around South America and back - a logged distance of 20.000 miles. Most of this trip was under sail and we used the Monitor self steering for most of the time. We lost our [boat's] rudder in the South Atlantic halfway between Estrecho de Magalles and Buenos Aires.The MRUD was rigged and steered us the remaining 500 nm to Mar del Plata in Argentina. We could, literally, have been lost without it."

Quote from e-mail received from Robin Davies, Around Alone particpant four times:
"Leg 1 is over, South Carolina arrived in Capetown without a rudder, and what will be documented is that the 2300 miles I sailed without a rudder are without a doubt the most difficult and demanding 2300 miles I have ever sailed - or ever want to sail.
"It was a far more difficult proposition than my 2500 mile jury rig sail in the southern ocean around Cape Horn to the Falkland Islands after my leg 3 dismasting in the 1994-95 BOC race.
"MRUD was a very significant part of my emergency rudder system, and without it - in so far as it was a piece of kit that should have been tried and tested beforehand - not left to the time of the emergency to use.
"I can only strongly recommend that all MONITOR users going offshore take the MRUD system as there (sic) emergency steering system, it will without any doubt get them into port should the ultimate mishap of broken rudder occur. I would strongly recommend they try it out beforehand."

Download the article 'Rudderless!', Santana magazine, January 2005 as a PDF file