Below Decks Autopilot DIY Part 3 (of many)

I am making some good progress on the project.  Over the past few days I have the drive aligned and the mounting foot bolted in. I threw together the wiring with temporary rudder sensor configuration and was able to successfully complete the Simrad autopilot installation program and drive test.  Everything is looking good.  Below are some notes for the alignment phase.

Drive Alignment:

The idea is to get things aligned so the drive is at the mid-way point when the rudder is perfectly centered.  Using a tape measure I hand centered the piston.  The Raymarine type 1 has 12″ throw so I set it at 6″ (as close as could).  I also unscrewed the drive end a few turns so it could either way for fine tune adjustment.  I then centered the rudder and noted that my tape mark on the top spoke of the wheel (helm) was centered as well with the spoke perfectly horizontal.

I connected the drive to the tiller arm and set the mounting foot on the base.  Did some alignment checks with a square and level to make sure everything looked ok.  I then drilled two holes through the foot and bolted it down with two SS 3/8 – 16 hex bolts.  I then checked center position by turn the wheel gently to the drive stop port and starboard and using a tape measure to check the height of what was the center spoke above the deck with the goal of identical measurements on either side (~23″ for a Sabre 36 with a 36″ destroyer wheel).  It required some tweaking and I wound up with a second set of mounting holes as I initially had the drive too far towards the center line.

Once I had everything aligned I rigged up the rudder sensor and ran through the calibration and alignment.  This will also show any inconsistencies with alignment.  The rudder sensor calibration should show consistent angles after setting one side.  During the rudder drive test everything sounded nice and smooth.  I then finished bolting down the foot with all four bolts.

During this phase I also measured for rudder bump stop modification.  The stops cannot let the drive exceed it’s limits which is 35 degrees on either side (assuming 10″ radius arm). The Sabre 36 factory setting is around 40+ degrees.  I gently pulled the tiller arm to the drive limit and then measured the gap.  In measuring I found out the  rudder  stop bar was a bit misaligned so one side needs a 5/8″ extension and the other a 3/8″.  I used drill bits like big feeler gauges to help measure  the gap.  I will post some pics of the bar and modifications next post.  I removed the bar to work on it off the boat in the garage.

I had some more time so I started drilling the 3/8″ hole through the rudder shaft and the long side of the tiller arm.  I used smaller bits to drill a pilot hole and it only took about 15 minutes to get through back side.  I am now working with a 10″ 3/8 bit to get through the far side and progress is slower.  I used WD40 as cutting fluid as it is easy to spray into the deep hole with the little straw.

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Below Decks Autopilot DIY Part 4 (of many)

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Link

Sabre Sailboat Yahoo Group

BTW – For those interested in Sabre Sailboats, please check the yahoo group.  I noticed that yahoo does a terrible job with SEO for their groups and it doesn’t really show up in a Google search for Sabre Sailboats.  There is an active community along with a rich archive of messages, photos and files that covers everything you want to know about Sabre Sailboats.  

Below Decks Autopilot DIY Part 2 (of many)

Project List

This project has many facets.  My posts may bounce around a bit but here is the list of specific sub-projects:

  1. Build/install platform for drive.
  2. Install tiller arm on rudder shaft
  3. Align and install drive
  4. Modify rudder stops for 35 degrees
  5. Install rudder reference sensor
  6. Install autopilot control head in binnacle pod (will replace old ST4000).
  7. Install autopilot computer + power
  8. Install compass
  9. Wire up everything (head, compass, reference sensor, computer) on the NMEA2000 bus
  10. Modify below deck steering system cover to fit over ram

This is not a project for the meek.  From what I understand pros could charge up to $5K labor for this type of job.  There is quite a bit of custom fabrication.

Drive Selection and Installation

If you have a typical quadrant/cable steered boat then you will probably need a linear drive and tiller arm.  There are some quadrants designed to have linear drive attached but my Edson quadrant is definitely not one of these.  It is aluminum and not designed to be subject to point load forces from a ram.

There are a few choices in autopilot tiller arms.  I decided to go with the Edson bronze arm.  It is not cheap but it is one fine piece of bronze alloy.  Edson will custom bore it for the rudder shaft diameter.  The Sabre 36 factory spec for my boat is 3.475″.  I used a micrometer to double check and found it to be within .003″ at the top so I went with the factory spec.  It fits perfectly.  Required a twist to work it on and snugs together when the clamp bolts are tightened.

One fine piece of bronze

One fine piece of bronze.  Took about a week to get from Edson.  Because I have hollow rudder shaft and no keyway I went with the through bolt.

Test fit over the top of the rudder shaft.  Should be perfectly snug

Test fit over the top of the rudder shaft. Should be perfectly snug with no gaps when clamp bolts are tightened

For the linear drive I choose a Raymarine Type 1 Linear drive.  When shopping around you have options for hydraulic and mechanical drives.  I went with the Raymarine Mechanical for a number of reasons: low power consumption, widespread usage, flexible mounting options and flexible installation tolerances.  It also has a decent manual.

Raymarine Type 1 in the box

Raymarine Type 1 in the box

I wanted to tackle the drive install first.  The Sabre 36 has a fairly cavernous area aft of the helm.  I can lower myself completely into the lazarette and get good access to the rudder shaft and the mounting surfaces.   I spent some time in there visualizing the work and decided to install the drive on the port side, perpendicular to the center line.  The arm will be installed facing forward.  The drive will be mounted to a wedge tabbed into the hull.

The first step was to attach the tiller arm and get it on centerline.  I then clamped a 48″ level to it and worked on determining the wedge location.  I accounted for the height difference between the drive mounting foot and drive end using some blocks of wood between the level and arm.  For distance I used the mid-position measurement from the drive manual.  I used a sharpie to start marking:

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Marking Locations

After the measuring was complete.  I did some scribing and built a wedge shaped platform using 1/2″ meranti marine ply.   This will be built up and tabbed in with west system and glass cloth.

Dry fitting everything

Dry fitting everything

Trying to keep the drive mid-extension for final dry fitting.

Trying to keep the drive mid-extension for final dry fitting.

Finally I was ready to start thinking about adhesion.  I decided first to install a mini-stringer to give the platform more attachment surface and stiffness.  The old paint and surface roughed up with a Multi-master and carbide grinding tip.

Stripping paint and roughing up the glass.  Using a vacuum to minimize dust in the boat.

Stripping paint and roughing up the glass. Using a vacuum to minimize dust in the boat.

Mini string epoxied in with first layer of tabbing

Mini stringer epoxied in with first layer of tabbing

Platform bonded to hull plus 4 #10 screws into stringer.  More tabbing coming soon

Platform bonded to hull plus 4 #10 screws into stringer. More tabbing coming soon.  Inside has been stiffened with a layer of cloth and west system before installation.

All bonding with done with West System and High Density bonding filler.  All tabbing done with no fillers.

Below Decks Autopilot DIY Part 3 (of many)

Working on the boat in the New England Winter

Most non-obsessed owners put their boats away over the winter.  From the fall to a reasonable point in the spring (mid-April?) the boats are covered, stuffed in a boat yard somewhere and  remain untouched.  The better heeled crowd may have their boat stored inside at reputable yard where pros may be doing larger projects.

For me working on the boat is therapy year round  so no reason to stop when others head for  Florida or the ski slopes.  I am lucky because I have the boat stored on my property (actually my driveway), I live in a town where this is allowed and acceptable (I am sure some of my neighbors are like WTF) and my wife lets me keep it there.  Also, I can do it because I drive a car with a low roofline and have a boat with nice bow overhang.  So the car goes under the boat about six feet, fitting like two puzzle pieces.

The boat stays plugged in with the battery charger on float and a few small space heaters are at the ready for when a project starts calling.  Yes, you do get strange looks from the neighbors when they see you on the ladder climbing in during a snow storm.

Using the heaters I can get the cabin warmed up for general work.  I have also done some epoxy/glass work by keeping one of the heaters focused on the work area until the epoxy is completely set (10-12 hours).

Today was a good example.  Relaxing Saturday – I wanted to get a few hours in on the autopilot project.  Patagonia thermals under the work pants, thermal socks and heavy hoodie pulled over a winter hat.  Put a heater down in the aft lazarette and I am ready to go.ImageImage

Below Decks Autopilot DIY Part 1 (of many)

Calypso (the Sabre 36′) came with a 20 year Raymarine ST4000 wheel pilot.  The best it could it do is steer a “snake wake” average heading in flat calm conditions while motoring.  Any helm pressure would just cause the thing to struggle.  It was never installed well to begin with.  The compass was installed on the rear bulkhead behind the helm when it should be installed near the center of motion.  I believe it also really needs a rudder reference sensor.

I am in process of ditching the thing and installing a below decks system with linear drive, computer, rudder sensor, etc.  This should be able to steer the boat under all in all but the most extreme conditions. It is a significant undertaking both in terms of time and cost but there are many reasons to have such a system:

1. Stress free single handing or shorthanded sailing.  I like to sail with my child, wife and others who could who may not be able to take the helm incase my attention is needed elsewhere.

2.  We like to do overnight deliveries to cruising grounds (Maine, South Coast, etc.) and it really helps to have a good autopilot at night when it can be harder to hand steer.

3. Also if there is inclement weather can duck under the dodger while the boat steers itself.

As of today I have started moving out of the planning stage and into the building stage.  I have acquired the following pieces of kit:

Edson Tiller Arm

Raymarine Linear Drive

Simrad AP components including AC12, AP42, RF25, RC42

Bunch of NMEA2000 Micro-C stuff to hook everything into my existing network.  I spent about a week measuring and test fitting various things.  Next post we will start to get into details.Type 1 Linear Drive

One fine piece of bronze

One fine piece of bronze

Test fit arm on shaft Measuring Marking Locations

Below Decks Autopilot DIY Part 2 (of many)

Welcome

Welcome to my blog.  I have been working in IT for over 20 years.  During this time I have seen the internet happen.  I have benefitted in countless ways from information garnered on the net.  This includes tons of stuff that has helped me professionally and in my personal pursuits.  This blog is a little space so I can give something back about something I am highly passionate about: boats.  More specifically sailboats.  I have owned five boats (so far) and maintained all of them in a DIY style.  During ownership of my first boat (1993-1995), a 63′ Pearson Triton, I did call in in the pros a few times but if I knew then what I know now it wouldn’t have been necessary.  

This blog will cover some interesting projects, sailing stuff or ask me anything.  My current boat is a Sabre 36′ which I have a deep affection for.  Anyway, on to the good stuff.Image