Installing the Monitor Windvane on Stops

For ocean sailing  I needed a windvane to self steer the boat.  A windvane operates by using the power of the wind and moving water to steer the boat.  In addition to working best when needed most (heavy weather) this system uses no electrical power!

I bought the monitor windvane second hand from an owner that had hardly used it on a J41. The previous owner had hit something with the windvane (it had some minor scratches) and Scanmar (manufacturer of Monitor windvane) offered to inspect it for free and concluded the scratches were only cosmetic. They also drew up an installation diagram specifically for my boat. It is amazing that they would do this for a second hand windvane. Talk about great service!

In the end I only needed to buy the upper tubes and the brackets. I was able to reuse the bottom and diagonal tubes from the J41 that the used monitor came from.

The most difficult aspect of determining the proper position for the upper brackets was in trying to provide proper 3-axis alignment of the Monitor, while at the same time locating the Monitor in the appropriate vertical and fore/aft dimension so that when Stops was loaded in cruising trim, the Monitor would perform as intended. This involved checking vertical distances from the bottom of the servo-pendulum to the water surface. The paddle when the boat was fully loaded for cruising needed to be 6 inches above the water. Since Stops was not fully loaded, I allowed for 1500 lbs of cruising load (about 1.5 inch of draft) and raised the monitor and upper brackets to make sure the paddle was about 7.5 inches above water level.

To accomplish the preliminary alignment and positioning check, I used my main halyard to suspend the Monitor in its approximate position. The next step was to identify the proper location for the mounting of
the installation brackets for the upper support tubes. This was
initiated by measuring and marking two lines equidistant from the
transom centerline, or from the backstay.

I marked and drilled the bracket holes and completely mounted and bedded the upper brackets.
I mounted the brackets using BoatLife Life-Caulk. Access to the bolts inside the boat was via an aft locker which required some interesting contortions to get access to the bolts especially the lower brackets which were well out of reach. I did not add any internal backing plates for the mounting brackets, but I did use large double washers as backing for the bolts. The one mistake I made was not remeasuring the holes needed for the tube after installing the bracket. After drilling the holes I realized the holes were not aligned. I then had to use a Dremel cutting bit to enlarge the holes on one side of each tube.

Then I temporarily mounted the Monitor on the two upper brackets, and used the main halyard to orient the Monitor so that it was level in the fore/aft direction. The lower mounting tubes and diagonal braces were cut and drilled to finish the installation. The lower brackets were mounted and bedded in the same manner as the upper brackets.

The final step was to mount the wheel adaptor to the wheel and route the pendulum sheets from the Monitor’s servo pendulum to the wheel adaptor. Since I had previously installed the Raymarine auto pilot with the wheel drive unit forward of the wheel, I mounted the Monitor wheel adaptor aft of the wheel. Connections were made by hose clamps

 

To lead the lines from the windvane to the wheel adaptor I installed a Harken blackmagic low friction double footblock. I had to create a mounting platform to raise the block by 1/4 inch so that the lines would be slightly elevated and wouldn’t rub on the deck.

 

The airvane course control line was run to one of the pushpit stanchions and secured with shock cord as suggested in installation instructions.

 
Below is a video of sailing with the Monitor just after I installed it.  It was an absolute delight, almost magic 🙂 It sails the boat beautifully, even in very light winds and downwind.

Things I’d do differently: Remeasure after every small step. Small deviations will require you to enlarge some of holes.

Cost: I paid $2000 for the used 2005 Monitor without the wheel adaptor; the new wheel adaptor and tubes and brackets came to about $1000. The harken footblock was $200. Total, $3200.
Time: This project took me 3 weekends.

Update in 2012 after 13,000 miles of sailing

The monitor windvane was hands down the best equipment I installed on the boat. It worked tirelessly in big ocean waves 24X7 with no issues whatsoever. I couldn’t have done my half circumnavigation without it. It also allowed me to be completely green just using wind and solar to power the electronics and fridge. If I was relying on a mechanical autopilot I would have needed a generator or have had to run the engines 2-3 hours a day on passage… apart from the fact that the autopilot quote was $7000 😉