Contents

Home

About

Captain's Log

Projects

Guest Book

 


Alberg 35 Site

Alberg 35 Members

Cape Horn Self-Steerer Installation

The existing autopilot aboard Tomfoolery, an Autohelm 4000 Wheel Pilot, is getting a bit long in the tooth after 15 years of service. While the electronics are still functional, the mechanical portions of the device are beginning to show their age and have experienced some periodic failures over the past 2 years.

After getting some very positive comments about the Cape Horn unit from friends who had one on their Cape Dory 36, I decided to install one aboard Tomfoolery. After a few e-mail consultations, Yves G. from Cape Horn came down to Watkins Glen to take measurements and a few weeks later a unit was ordered for delivery in the spring of 2011.

In mid-April 2011, the package arrived. The contents are shown at the left.

At the present time, this project is on hold pending the completion of other repairs and updates to the boat, but there should be more information here by mid-summer!

2011/08/20 - The first step to installing the steerer is to have a very, very clear and specific plan. This involves reading (and rereading) the installation instructions and mapping out each step so that there will be no surprises later on. Part of the planning phase is to lay out the exact location of all of the equipment and to compile a list of supplemental hardware that will be needed to make all of this functional.

2011/08/27 - One of today's tasks was to re-level the boat in preparation for the wind vane installation. Having the boat level will make it a bit easier to ensure the wind vane is mounted straight. From experience I can say that the cabin sole is very close to level when the boat is floating on her lines, so that was the base line used to determine how to move the boat.

Side to side, the boat was reasonably level, simplifying the exercise. According to the level on the cabin sole, the aft end of the boat had to be raised 1.5 inches. A 12-ton jack was used and, after some groaning from the cradle, the stern was elevated enough to get everything aligned for the wind vane installation.

2011/09/03 - Last week I spent some time leveling the boat. This week I set up some strings to mark the water line so that accurate measurements could be taken for positioning the new windvane. Strings were "eyeballed" to the water line and then checked with a level. Turns out that eyeballing is pretty accurate. A plumb line was then set up just starboard of the center line of the boat in order to get measurements of the slope of the transom.

The stern tube of the wind vane needs to be at least 16 inches above the water line in order to minimize drag on the steering oar. The more significant constraint, it turns out, is that the stern tube needs to be positioned to allow the quadrant to rotate a full 360 degrees inside of the lazarette.

Measurements were taken inside and outside the hull to determine the position of the stern tube. To help determine the position of the hole, a disc of cardboard was cut to show the sweep of the quadrant on its axis.

Using this information, an estimate was made for the position of the hole and a 1/8" pilot was drilled. The disc was positioned and then the hole was enlarged to 1/4" so that a rod could be inserted with the actual quadrant at its end. This resulted in discovering that there was some interference at the bottom of the quadrant's arc, so the hole was moved upwards an inch and the process was repeated. Again there was some interference so the hole was moved up another half an inch. This time, everything fit well with swing room for the quadrant. Note the high-tech leveling jig for the drill.

The stern tube was dry-fit and everything looked good. The next step is to put the stern pulpit back in place to verify whether or not it projects past the stern gunwale. This is necessary to determine how far the stern tube should prenetrate through the transom. Unfortunately, daylight was waning at this point so the job will have to wait until tomorrow.

2011/09/04 - Worked with the wind vane some more today. Temporarily bolted the stern rail back onto the boat so that I could check for possible interference between the rail and the vane mast and steering oar. Also wanted to verify that the vane quadrant could swing completely around to allow for storage of the steering oar by lashing it to the vane mast. Spent most of the afternoon lining things up and marking them for trimming and adjustments.

The support/stabilization struts for the stern tube are proving to be a challenge to position and fit, but I think I finally have it set. My preference is to tie them to the underside of the deck so they don't act as "catch-alls" in the bottom of the lazarette. The vertical supports for the vane mast pose a different challenge, as there is the possibility of an interference problem with the stern rail. The dry fitting also suggests that the stern light may have to be relocated for better visibility.

2011/09/05 - Spent more time trimming the supports for the wind vane stern tube and finding a piece of wood that can be used as a block on the underside of the deck to hold the mounting screws for the struts. More photos to come. Stay tuned.

2011/09/11 - Had some help today from crew members Jon and Jim with some of the chores that take more than one pair of hands. Together we mounted and aligned the stern tube for the wind vane of the Cape Horn steering unit. Later in the afternoon, the tube was glassed into place and left to cure. There's no going back now!

2011/09/24 - A small bit of the epoxy that was left over was used to clean up the bead around the exit hole of the Cape Horn wind vane. When we're all done, a bead of silicone will dress up the hole and provide some protection against the sun and weather.

2011/09/25 - With the stern tube of the wind vane glassed in place and secured, the mechanical workings were installed and the quadrant was bolted into place.

2012 - Got the boat back into the water after a late start, so I spent some time sailing before getting back into "project mode" to finish this up.

2013/06/12 - Tomfoolery is back in the water again and the wind vane is, by and large, assembled. However, the vane is only temporarily supported with some lashing to the stern rail. This does not really conform to "Bristol fashion". I tried to find a good place for the braces supplied with the wind vane, but all they did were interfere with other things on the already cluttered aft end of the boat. The idea then came to use the stern pulpit (which is now quite solid following repairs to the deck) as a support for the vane tower.

A solid block of wood could be made to do this without taking up any real estate on the deck. Since this block of wood is in a very visible location, I decided to make it out of mahogony. The first step was to laminate up some boards to get a block thick enough to wrap around the rail and vane tower.

The boards were cut a little oversized so that alignment would not be too critical during glue-up.

2013/06/26 - The next step was to route a grove in the bottom "half" of the block to match the shape of the stern pulpit. While the rail is a round, one-inch pipe, it curves on a gentle radius of approximately 48 inches. Time to build a jig to route this curved channel. The challenge is to do it more than once in a consistent fashion because we also need to route the upper half of the block. Below are some photos of the jig I built and calibrated over the course of the next two days.

The pivot point consists of one of the dogs that can be used in the workbench clamp. I figured that by making the pivot hole in the jig the same size as the bench dog holes, I would have a more versatile setup for future projects.

After cutting a few trial pieces of (less expensive) wood, I came to the realization that in order to cut a repeatable groove that would line up between the top and bottom pieces, I needed some sort of alignment guide to consistently place the block(s) on the bench. The result is shown here, along with the results of the stern rail groove in the lower half of the mounting block.

Here's another view with better detail of the guides that position the piece along with the hold-down that keeps it from moving around as the router is passed over to make the multiple cuts needed to get the required groove depth.

Here's the finished product prior to varnishing, along with some snapshots of how it is held together and assembled. The sketch has my notes with the original design.


Next step is to varnish and then install on the boat!

2013/06/29 - Two coats of varnish and now time for a final fitting of the brace. Happy to report that it fits quite well and provides for a snug and solid support for the tower.

Here's a view showing the entire tower with the vane attached. Next step is to finish the varnishing and to start installing the control lines for everything.

2013/07/20 - Now that the tower is in place and the "heavy duty" exterior work is finished, it's time to focus on the internal mechanics of tying the wind vane in with the existing steering system. One of the big challenges is how to attach the control lines to the steering quadrant. With the long, narrow ends of the Alberg 35 and the extreme rake of the rudder (about 45 degrees), there isn't a lot of room under the cockpit sole to install a second tiller or quadrant for use by the wind vane, so I decided to attach the control lines to the existing quadrant.

Not wanting to make permanent and potentially weakening modifications to the quadrant, I decided to try to fabricate a short strut that could be clamped to the quadrant. After making some measurements and heading up to the boat a couple of times, the result is shown here.

As you can see, the strut is simply a 1-1/4 inch angle iron that has been trimmed to fit inside the quadrant and is held in place with a pair of beam clamps. The two pulleys provide the attachment point for the wind vane control lines and provide a 2:1 mechanical advantage as recommended in the installation manual.