Sunday, November 22, 2009

Self and Emergency Steering

The Single Handed Sailing Society (SSS) hosted a seminar the other night on options for self and emergency steering systems on small boats.  This was one of a series of seminars in preparation for the next Single Handed Transpac in June 2010.  This series would be useful for anyone interested in that race, the Pacific Cup or a long distance cruise.

Hans Bernwall from Scanmar International presented on three products.  The Monitor Windvane is a servo-pendulum self-steering device.  These are excellent units that are driven by apparent wind.  With no electrical components that can be much more reliable than electronic autopilots.  We have used an for runner of the Monitor, an Aries, with great success on Maitreya.

The MRUD is an emergency rudder conversion for the Monitor.  It operates by locking the lower rudder on the vane in a fixed vertical position.  A larger blade is fitted to the lower rudder.  The blade then pivots on it's axis like a normal rudder steering the boat.

Lastly, Hans discussed the SOS Emergency Rudder.  This has a rudder blade that is similar in construction to those of the Monitor and MRUD.  A separate set of mounts are provided to fit to the transom.  The tiller arm can be custom bent to work around a back stay or other permanent gear that may be between the transom and the cockpit.

All of the Scanmar gear has seen thousands of miles of use in races such as the SHTP, BOC, and Pacific Cup.

One of the problems with any emergency solution is fitting it at sea.  This will be compounded by the fact that the skipper in an SHTP is alone. Hans suggested using a bosun's chair rigged with three lines.  The primary vertical lift line would be a halyard.  The halyard should be supplemented by two horizontal preventers led around the sides of the boat.  The side lines would prevent wild swinging aft of the boat.

Greg Nelson gave a talk on building an emergency rudder.  This focused on foam, fiberglass and carbon fiber.  The Scanmar offerings are meant as a "limp to port solution".  Greg was promoting the idea that a properly designed and built alternate rudder could keep you racing.

Greg's talk stressed the fact that the forces involved in steering a yacht at sea, racing or not, must be respected.  Huge loads can be placed on the mounts, shaft and blade of the rudder.  Top quality materials and construction are required.  Greg told of some SHTP emergency rudders he had seen made of solid wood or common foam insulation.  He said that these failed very quickly when put into service.

One of the race committee chairmen, Bob Johnston, gave a talk on auto pilots.  It was agreed that the best autopilots come from NKE and B&G. The only problem with these is that they are likely to cost more than your average SSS boat.

This leaves the fleet with the middle and low end offerings from Raymarine, Simrad and others.  The group for the most part had had good experiences with these.  Some people had installed the hydraulic versions which are much more powerful.

Bob talked about the need to keep all components dry.  The electric rams are not waterproof, so he has covered his with a loose fitting sunbrella booty.  Greg Nelson and Bob both underlined the need for spare parts and full backup units.  Thought and planning for easily swapping units is required.  This may dictate dual wiring and mounting systems for the primary and the backup.

The big takeaways from the seminar were planning, testing and redundancy.

Thanks to the speakers for putting this on.

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