AutoHelm 7000 with Type 1 & 2 Linear Drives

									by Wayne Strausbaugh

System:  My AutoHelm 5000 autopilot with Type 1 Linear Drive was installed in 1983 aboard my Tayana Vancouver 42 Center Cockpit cutter.  The boat weighs in at around 32,000 pounds in cruising form, has a short 33-foot waterline, 1000 square feet of working sails, 6-foot draft with a long but not full keel, and is considered heavy-displacement.  A Type 2 Linear Drive was added in 1987.  Either drive could be utilized but they would not both fit at the same time.  They have separate attachment bases due to length of the arms. The AutoHelm 5000 control head was replaced with an AutoHelm 7000 in 1994. 

Performance:  The AutoHelm 5000 autopilot with Type 1 Linear Drive was used exclusively for almost 6 years from Texas through the Caribbean to South America.  About 15,000 to 18,000 miles was sailed/motor-sailed with the autopilot.  The Type 1 Linear Drive was sufficient for my Tayana 42 but after I installed the Type 2, I could see that the Type 1 was approaching its limits when asked to steer downwind in large following seas.  It could handle up to about 8-foot seas.  The AutoHelm 5000 Control Head needed repairs twice.  The linear drive never needed repairs.

    The Type 2 Linear Drive has been used for 27,000 to 30,000 NM’s. The AutoHelm 7000 control head has been used for around 25,000 miles.  No repairs were required except for the replacement of a rubber gear wheel on the linear drive motor due to wear.

Initial Installation:  the autopilot installation required modifications to interior frames to achieve a sufficiently reinforced mounting base for the linear drives. An athwartships frame was added to form a strong, box-like structure for the linear drive.  The frame consisted of two pieces of ¾-inch plywood glassed together.  Thick layers of fiberglass covered the plywood.  This was glassed to a fore-and-aft oriented frame that was installed by Tayana at the factory to hold the rudder cables and rudder stops.  The two Pull-Pull steering cables terminate at this frame and the cables run from there to the steering quadrant. This “box” for the linear drive now consisted of the Tayana frame running fore-and-aft on the port side, my new athwartships frame glassed into the hull on the starboard side with the port side of the frame glassed to the forward end of the Tayana rudder-cable frame.  The hull running aft to my “double-ender’s” stern completed the third leg of this box.  This frame structure is immensely strong and hasn’t showed the slightest sign of fatigue or cracking after being used as an attachment point for the linear drives – for at least 40,000 miles of autopilot use – mostly at sea!
     An Edson autopilot attachment arm was secured on the rudderpost above the quadrant.  It has never bent, cracked, loosened, or given any problems whatsoever.  In 40,000 miles!

Summary:  I use the autopilot about 95% of the time, even when transiting the ICW.  With the AutoHelm 7000 control head and rudder sensitivity set to its highest point, the autopilot performs particularly well in narrow channels.  It often only needs adjustment every 1/8 to ¼ NM, keeping the boat within 10 to 15 feet of an absolutely straight course.   At sea, the sensitivity is set to 2 or 3 (the lowest settings).  The autopilot appears to be adaptive, fine-tuning the steering movements over a ten minute period until it steers exceptionally well.  It will routinely outsteer me in downwind conditions in anything up to 10-foot seas.  And I am a really GOOD helmsman!  It starts off roughly but gets better and better.  I also hook my computer to the autopilot and it once again tends to better my performance.  I am fully satisfied with this setup!