Back in the Scanmar Monitor Self-Steering Business

Messy cabin workshop

I had some spare time between projects while staying at the Fort Myers Yacht Basin, so I decided to rebuild my Monitor self-steering gear. The reason is that twice in the past six months it had jumped its gears, which Ron, the designer at Scanmar Marine, wrote me indicated worn bearings. Furthermore, the thing was installed about 1994, so its parts were twenty years old. I bought Scanmar's bearing kit and used the Yacht Basin's utility barge to allow me to unbolt and remove the gear, then my neighbor Greg helped me haul it up to the dock. Next, I carefully marked all the support tubes so I could put them back together the same way, removed them, and rigged a block and tackle off the backstay to lower the gear into my cabin, disassemble it, and begin the task of replacing bearings and bushings. For about a week, the gear dominated my life as I had to share everything with all these pieces, tubes, and gears.

Visible in the photos above and on the left are the main frame and many of the pieces requiring new bushings. The Scanmar design primarily uses Delrin bearings because they are self-lubricating. All that can clog them is salt, which is usually cleaned out by rain or a marina-fed garden hose. This is a great advantage for a mechanism constantly drenched by ocean waves. However, Delrin is not cheap. The parts cost $155, including shipping, and arrived in the smallest Priority Mail boxes USPS sells!

Parts on dining room table

 I put it all together. In fact, I put it all together several times, in my clever attempts to outsmart the Scanmar engineers. I actually studied the Parts diagrams many times, yet invariably got something in backwards and had to start over. For one thing, though, the parts are very beautiful after some study.

Close-up of ring & pinion gears and actuator shaft. Lovely!

Here is a close up of the water vane operating gears and the actuator shaft that moves them in response to movements of the wind vane that then moves the tiller to catch the wind.

Gear in the cabin

The hardest task was reassembling the gears, mainly due to the lack of a shop bench and a strong vise (I turned my fold-out dining table into a workbench and used a very small Stanley vise I bought for splicing work). I found a concrete block that gave me clearance for the water vane shaft and rigged my little vise to hold everything in place while I carefully replaced the main gear shaft with its new bearings, shown at left.

Gear in the cockpit

 I wrecked some parts in the re-build, but Suzy at Scanmar promptly sent me new ones. I think she did this three times, only charging me once. To my credit, I never wrecked the same parts twice! Finally, the job was mostly done and I hoisted it out of the cabin into the cockpit. To do so, I had to fold back the canvas dodger in front of the cockpit, then again rig a block and tackle from the backstay (I used an old carabiner Adam Tripp gave me that, hooked to the main halyard and the block and tackle, could slide along the backstay until it was positioned directly above the hatch).

Gear on dock

Next, I hauled the main body to the dock in order to reattach all the support tubing. To my horror, I discovered that my relentless cleaning and polishing while waiting for parts had dissolved all my careful markings! There are four tubes that can go one way or another, so as I remember from my math classes, that is 4x3x2x1, 24 combinations. It took some time and patience, believe me, but I finally got it, as you can see on the left.

Gear on barge

Following reassembly, I changed the block and tackle position and lowered the gear onto the barge. Barges are tricky in that they reside in water so that pushing achieves an opposite reaction, likewise pulling. Plus, due to years of stress and strain on the gear, the hole positions had shifted. I did not have a good drift, but a bicycle trip to Tropical Hardware for a spike solved that problem. All in all, it took most of the day to remount the gear and I ended up with some pretty chapped lips but a mounted self-steering gear!

Watervane reflecting the dawn

Once remounted, I only had to readjust and reattach the control lines, and I can now go back to, if not a normal life, a life similar to the one I led before I decided to become a Monitor repairman! The result of all my work and expense is quite lovely, really. My new self-steering gear is clean and polished and the workings are whisper-fresh. I plan to try it out soon, and I am positive it will work very well.

Self-steering gear ready to go!

The photos show the water vane up, which is the position while in port or traveling by engine (one photo was taken early morning and reflects the dawn sky). It is like a rudder. The water vane locks in its down position when it is released from a rope holding it. Then, the wind vane, a thin wooden board like a sail and kept onboard when not in use, attaches to the top of the gear. The wind vane is aligned with the course, then control ropes are attached to the tiller. As the wind shifts or the boat moves off the wind-course, the wind vane moves, causing the water vane to move and the tiller to move, thus compensating for changes as the boat returns to the wind-course. Note this action is not adjusting to a compass course. The gear only cares about the wind, so the skipper can adjust sails perfectly and then be assured they will stay adjusted. There is no reason to man the tiller and most of the crew can go below for tea while the watchperson scans the horizon and checks for hazards. The single-handler can even go below for a quick nap!

One real plus about doing this work is I now have a fine understanding how the gear works. In addition, I have found that the Scanmar team, Ron and Suzy, are supremely dedicated to their customers; furthermore, they are friendly and super-helpful. It is nice to know that such people exist. They show the way that American business should exist. Thank you!