From the Galley: Fresh Tuna Ceviche

Last fall, Bill and I helped deliver a Hylas 56 from Annapolis to Ft. Lauderdale. We stayed inside the Gulf Stream for the majority of the trip, but pulled out the fishing gear when we hit the warmer waters of the Stream off North Carolina.

Bill reeling in the big one!

Not long after putting out the rod (we lost several lures on the hand lines), Bill caught a nice sized big eye tuna! 

Nate with our catch of the day

In anticipation of catching fish, we brought a bag of herbs, limes, wasabi, etc. just in case. 😃 Even with a crew of 5 on board, that single tuna provided several awesome meals -- from sashimi to ceviche, to seared tuna steak salads -- and we still froze 1/4 of the fish for the owner to enjoy with his family.

It's hard to beat fresh tuna, and our ceviche was definitely a crew favorite! We've used this recipe with shrimp and squid, or you can substitute any fresh fish or seafood you have (snapper, mahi, scallops, or octopus all work well).

Only fresh seafood should be used for this dish since it is "cooked" by the acidity of the lime juice. Once mixed, it should marinate for at least 1 hour, but not much longer or the seafood will get rubbery.

Fresh Tuna Ceviche

Ingredients:

• 1 pound fresh tuna cut into bite sized pieces
• 3 tablespoons fresh lime juice (2-3 limes)
• 1 tablespoons olive oil
• 1 tablespoon white vinegar
• 1 handful of fresh cilantro, chopped
• 2 jalapeno peppers, minced (depending on how hot you like it and how hot your peppers are, use or omit the vein and seeds -- I always add the seeds and veins of at least one jalapeno)
• Pinch of sugar
• 1/4 cup minced red onion
• 1 medium-large clove garlic, minced
• Salt and pepper to taste

Preparation:
Combine all of the ingredients, stirring to make sure tuna is coated with lime juice. Cover (preferably in an airtight container) and refrigerate for an hour. Serve with tortilla chips. 

Note(s):
If you want to use squid or octopus, its best to blanch first. Combine all other ingredients in your bowl. Meanwhile, bring water to a bowl, add your seafood and blanch for 1 minute. Remove immediately from heat, drain and put seafood in an ice or cold water bath for 5-10 minutes. Once cool, add to your lime juice mixture and marinate.

If the peppers are too hot for your liking and if you have it on board, add some chopped avocado to the mix before serving.

Enjoy!

Replacing Phoenix's Rudder Part 2: Executing the Plan

Once we identified the issues with our old barn door rudder and hatched our plan, it was time to haul Phoenix out of the water. We didn't know exact dimensions and couldn't take any accurate measurements until she was out of water, so we were eager to see her blocked and to get to work.

Hauling Phoenix out of the water

Phoenix on the hard and ready for her new rudder

As soon as they were done power washing the boat, we took rough measurements and ordered the material. The old rudder was fiberglass over plywood, yet we didn't want to go down that road. Instead, we opted for one of our new favorite marine construction materials, Coosa Bluewater board.

As I mentioned in a previous post, Coosa is high density urethane (HDU) material reinforced with layers of fiberglass. HDU is a strong, naturally waterproof material that is much lighter than wood, thermally stable, paintable, and can be machined much like wood. Coosa combined these properties with the strength and structural properties of fiberglass into two varieties: Nautical (reinforced with continuous strand fiberglass) and Bluewater (reinforced with layers of both continuous strand and woven roving fiberglass). 
 
Before we could do anything with the Coosa board, we had to remove the old rudder by unbolting the barn door from its exoskeleton of plates and straps. The rudder was REALLY heavy (> 150 pounds) and essentially negatively buoyant, further adding to the rudder feedback we were trying to correct!

Phoenix's old rudder unbolted from the rudder post, plates and straps

Phoenix's old rudder

We used the old rudder as a template, and began by cutting 6" off of the trailing edge. We briefly considered modifying, tapering and reworking the old rudder rather than building a new one from scratch, but found that some of the plywood was wet inside the bottom of the old rudder, and we didn't want to worry about future delamination.

Wet plywood inside Phoenix's old rudder

We traced the old rudder on a 4x8' sheet of 1/2" Coosa Bluewater to get a baseline of how the new rudder would fit against our curved rudder stock, then added the leading edge that extends forward of the rudder towards the metal skeg. Once happy with the layout, we used a circular saw and a jigsaw to make the cutout. 

Laying out the design of our new rudder

Our plan was to laminate several sheets of Coosa Bluewater together to make the full thickness of our NACA 0010 foil rudder, which we would then shape and taper accordingly (with the thickest part of the “chord” being 3-1/2” thick and the trailing edge tapering down to 1/4”). We printed out a plot for a NACA 0010 with our chord thickness from airfoiltools.com, then transferred it to a scrap piece of fiber reinforced plastic (FRP) to make our rudder foil template.

NACA 0010 rudder foil and elliptical leading edge template cut out of FRP

The airfoil shape was more important in the bottom section of the rudder behind the small metal "skeg;" since everything above and in front of the propeller was behind Phoenix's true skeg, it was an extension of that teardrop/foil and just needed tapering and shaping. 

Before we could start laminating the sheets together, we test fit the 1/2" cutout and made the necessary modifications for optimal fit.

Test fit of rudder's Coosa inner core

Once satisfied with the initial fit, we laminated two 3/4" Bluewater boards to either side of our 1/2" core material using Precision Board's PB Bond HDU Adhesive to give us a 2" thick rudder shape and did another test fit. We were hoping that the stainless straps would flex enough to allow us to slide the 2" stock in between the straps, but no dice. So Bill marked where each strap was located and routed in slots for the straps and plates. 

Slots added to help bury the metal straps and plates

Next, we prepped four 1/2" pieces to add to either side of the rudder. Two pieces were laminated to the bottom portion (below the straps) with PB Bond Adhesive. The other two pieces, which we referred to as "ear muffs," would cover/encapsulate the straps. We attached the "ear muff" sections to the Coosa sandwich with screws so they could be shaped but still removable. Once they were fitted in place, we attached our NACA 0010 template to the bottom edge of the rudder, and prepared for shaping.

 
We used a router to get the general shape for the rudder. We set up a fence, moved in 3/8" increments, set the depth to match the template, and Bill routed each section. One issue when working with Coosa Board is that a TON of dust and fiberglass flies everywhere! So his trusty assistant was in charge of vacuuming up as much flying fiberglass dust as possible during each pass and then afterwards. We nearly filled an 8 gallon Shop Vac (fitted with a Gore-tex filter) each day, and had to rinse off the outside of the vacuum and hose daily.

Bill in action shaping Phoenix's new rudder

Once we had our general foil shape, went back to the marina for another test fit. We slid the rudder in place and gently set the "ear muffs" in place covering the straps. To keep our foil shape, Bill cut off the small straps that were sticking out of the "ear muffs," so all the straps would be covered.

Test fit of Phoenix's new rudder with the "ear muffs" in place

Cutting the straps so they would remain buried inside the new rudder

Next, it was time to sand and smooth the rudder's shape. The router steps worked as contour lines to help us maintain the foil shape, and we kept the template in place as a guide. We also used the elliptical "nose" of the template cutout to help guide us while shaping the lower leading edge of the rudder.

We then used 3M Marine Premium Filler (vinyl ester putty) to fair the seams and fill the screw holes used when laminating the sheets of Coosa together. [Note: HDU boards tend to slide when gluing with PB Bond. Clamps, screws, or heavy weights are necessary when laminating sheets and to keep the material from moving. The screws are easily removed after the adhesive cures.]

Once satisfied with our shape, we were ready to fiberglass the rudder. We wanted to do as much of the work out of spot as possible, so we laid several layers of glass everywhere except where the "ear muffs" would attach before installing the rudder. We used vinyl ester resin for glassing and fairing with microballoons since it is much better for under water applications than either epoxy or polyester resin. 

We headed back to the marina and were finally ready for installation! First, we had a welder come and check and retack all of the welds on the rudder stock. Then, we slid the laminated inner core between the stainless plates and straps, adhered them with 5200 urethane caulk, then through bolted the rudder in place. The "ear muff" panels were then attached with PB Bond. 

The majority of the leading edge on our rudder (including the "ear muff" panels) is behind Phoenix's 4.5" thick fiberglass skeg and propeller aperture. To optimize water flow and fully encapsulate the rudder post (which is at the max chord thickness), we needed a broader elliptical shape for this portion of the rudder. We made another FRP template of a NACA 0016 foil, and used it along with the 3M Marine Filler to create an elliptical leading edge before fiberglassing. We added chopped mat fiberglass to the Marine Filler to add strength in this area as well.

We also used the 3M filler to fair in the plates attaching the metal "skeg" to the fiberglass skeg and rudder shoe. We contemplated removing the metal "skeg" altogether, but it is welded to the rudder shoe and serves as an ideal spot for sacrificial anodes and protects the rudder -- so we reshaped it a bit instead for better water flow across the bottom leading edge.

After several rounds of glassing, fairing, and sanding, we applied several coats of Interlux Interprotect 2000e as a barrier coat and primer, followed by 3 coats of Petit Trinidad 75 anti-fouling bottom paint.

Barrier coat applied to Phoenix's new rudder

Phoenix's  new rudder complete!

With both of us hustling, the project was complete and Phoenix was ready to go back in the water! In addition to the building the rudder, we installed new depth and speed transducers, replaced the Bobstay fitting, re-pitched and polished our Max-prop (it was slightly over-pitched), and sanded and painted Phoenix's bottom with 3 coats of Trinidad 75 -- not bad for 3 weeks worth of work!

Eager to reap the benefits of our labor, we set out for a several weeks of sailing shortly after splashing. We've put several hundred miles on the new rudder so far -- in light and heavy air, heavy chop and following seas  -- and can report that we are EXTREMELY happy with the improvement in Phoenix's performance. We've gained about a knot of cruising speed, but more importantly, she handles with ease. We've had to change how we approach a dock since she has at least twice the glide range, you can let go of the wheel when tacking, and we no longer have to reef early. She easily carried full main and genoa in 18-25 knots apparent, which we wouldn't have dreamt of doing before.

 Nothing better than when a plan successfully comes together!

Phoenix happily at anchor

 

Replacing Phoenix's Rudder Part 1: Identifying the Problem

At some point in Phoenix's history, a previous owner replaced her rudder and installed a large, flat, barn door rudder. Our assumption from the beginning of her restoration was that this was done to combat weather helm. Why else would you put a barn door rudder on her?

For the uninitiated, weather helm is a term that describes a boat that sails with its tiller or wheel slightly angled to the windward side of the boat. A few degrees of angle -- 3 or 4 degrees -- is considered ideal: the rudder steers the boat and provides lift (like the flaps on an airplane wing), the helm feels light and is easy to steer, and if you let go, the boat will round up into the wind and the sails will luff (i.e. not sail away in the event of a man overboard). With too much rudder angle, the helm feels heavy, is difficult if not exhausting to steer, and the boat loses efficiency. Rather than provide lift through the water, the rudder drags, eventually stalls and acts more like a brake than a wing.

In design terms, weather helm is a result of an imbalance between the boat's center of effort (CE) -- geometric center of the sail plan -- and center of lateral resistance (CLR) -- geometric center of the underbody. Essentially, the CLR is the imaginary pivot point for the boat and the CE is the driving force location acting on the sail plan. If the CE is too far aft (on top of or behind the CLR) the boat will have weather helm.

Convinced we needed to combat weather helm and move our CE forward, we made nearly every textbook modification there is:

• We already had the bowsprit, but added a new, high aspect tri-radial genoa replacing the old bagged out genoa
• Reduced the rake in the masts, standing both main and mizzen masts up to only 1 degree of rake
• Purchased a new mainsail that could be easily flattened
• Installed a longer (94") traveler for the main sheet
• Reefed (reduced) sail often as the winds picked up

With all of these improvements, Phoenix sailed remarkably well for a boat her size in light air, easily moving 50-60% of wind speeds. However once the breeze picked up above 14 knots with full main and genoa, the helm would get increasingly heavy and difficult to steer. The heavy helm was felt even upwind with the genoa alone.

After sailing Phoenix with the new rudder angle indicator we installed with our Pypilot autopilot, we were very surprised to see that we only had 2-4 degrees of rudder when the helm felt heavy.  All this time we thought we were dealing with weather helm when clearly we were dealing with something completely different!

We decided it was time to look below the waterline and take a hard look at Phoenix's underbody, and specifically at the rudder. We began researching rudder design, spoke with several naval architects, did our usual homework, and determined that what we were experiencing was actually excessive rudder resistance or feedback, turbulence and drag caused by our oversized barn door rudder.

There are very few Christina or Andromeda ketches out there for comparison, but we knew our rudder was VERY different from the original design and from the only other production-built Christina we know of.

Andromeda 48 Rudder Design

Christina 49 Hull #2 Rudder

Phoenix's Old Barn Door Rudder

Unlike the Andromeda design, both Phoenix and her production-built sister ship have bent Monel rudder stocks fit into reinforced Monel rudder shoes. This allows for a larger propeller, and enables us to remove the propeller and shaft without dropping the rudder. That's really where the similarities end.

Our rudder was much deeper and longer (fore and aft) than either known counterpart. The top portion of our rudder was cut off at the waterline rather than running parallel to the hull. A smaller stainless "skeg" was attached to the fiberglass skeg, presumably to protect the deeper addition and to attach sacrificial anodes, but it was wasn't faired in. Not to mention, whomever made Phoenix's barn door rudder seems to have gone out of their way to add more drag by creating an exoskeleton of straps, plates and bolts to attach the flat plywood board.

The extra depth wasn't necessarily a bad thing, as it gave the rudder some clear water below the skeg. However, a flat board rudder was really the least efficient rudder design possible. While easy to manufacture, they stall early -- typically after about 5 degrees! The flat board caused water to eddy under the bottom of the rudder rather than being redirected around the trailing edge, which reduced the steering efficiency. Instead of allowing the water to flow naturally across the rudder and provide lift like an airplane wing or sail, the flat board created turbulence and drag with every turn of the wheel. Changing the design of the rudder to make it more like a proper foil would be much more efficient and allow for streamlined water flow across the rudder.

NACA foils are the most popular shapes used in rudder and keel design. Developed by the National Advisory Committee for Aeronautics, the shape of a NACA foil is described using a series of digits following the acronym "NACA." Many boat designers use a NACA 0012 for rudder design -- a symmetrical foil shape with a 12% thickness to chord length ratio (i.e. it is 12% as thick as it is long). The NACA 0012 is best for boat speeds up to about 6 knots; faster speeds (6-8 knots) can warrant smaller percentages, such as the NACA 0010 (10% as thick as it is long).

The additional length of our rudder blade (fore and aft) was also part of the problem. While adding extra area to a rudder can make it more efficient, there is a fine line between adding efficiency and adding too much resistance -- or feedback. Making a rudder too long puts undo back pressure on the trailing edge, and also contributed to the heaviness we were feeling on the helm as the breeze picked up. This excessive rudder feedback can be mistaken for weather helm since they both make steering difficult; however the root cause is rudder size and resistance rather than the CE or sail plan.

Our metal "skeg" was another issue. While it protected the deeper rudder from crab pots and other debris and allowed for a sacrificial anode, the lack of fairing disturbed the water flow and added even more turbulence in front of the rudder and drag.

Yet the biggest problem was the "Franken-rudder" exoskeleton of bolts and straps along the rudder's leading edge creating a large mount of drag. The plates, straps, bolt heads and nuts that were protruding from the surface produced too much turbulence over the rudder and reduced lift. This was yet another major factor that caused the rudder to stall early. It was as if we were sailing with a rudder full of barnacles that we could never remove! To make matters worse, anti-fouling paint didn't stick well to the exposed straps, so without continually scraping, we literally were sailing with a rudder full of barnacles!

All of our research pointed to the fact that we needed a better rudder. So, we developed a plan to build a new rudder for Phoenix and scheduled a haul out at a local marina. Our new rudder would have:

• A shorter chord length (fore and aft) than the existing rudder but still longer than the Andromeda specification, 
• A NACA 0010 airfoil design, 
• All of the rudder straps and fasteners buried inside the rudder for a smooth, efficient flow, and 
• A small  amount of area in front of the rudder post to provide some balance and "power steering" to the helm

Our plan to modify Phoenix's rudder

Just like that, a plan was hatched. Stay tuned for Part 2 -- the new rudder design, and how we built it!

Making a Hatch out of HDU Board and Coosa Composites

None of Phoenix's original hatches were intact when we bought her. The hatches that did come with Phoenix did not fit properly, as the previous owner resized each hatch opening when he began re-decking the boat. We had already built new hatches on the foredeck and aft cabin as well as the butterfly hatch on the main cabin, and had made a "temporary hatch" on the aft lazarette out of ipe and old Lexan.That hatch was never intended to be a permanent solution, and the time had come to design and build a new hatch.

Our other hatches are made of camaru or teak with Lexan, and were built to let light into the cabins. The lazarette, on the the other hand, is a storage area on the aft deck that doesn't need Lexan. With Phoenix's canoe stern, the aft deck is narrow, so we wanted to make the most of the real estate and have a strong hatch that could be walked on, so a nonskid surface was a must.

We had some 1/2" high density urethane (HDU) board left over from our windshield coaming rebuild, and some scrap 1/2" Coosa Bluewater board as well. As we mentioned in the windshield coaming post, HDU is a strong, naturally waterproof material that is much lighter than wood, thermally stable, paintable, and can be machined much like wood. It comes in a variety of thicknesses, and it works well with fiberglass and epoxy.

Coosa is HDU material reinforced with layers of fiberglass. It has all of the properties that we love about working with HDU, along with the strength and structural properties of fiberglass. It comes in two varieties: Nautical (reinforced with continuous strand fiberglass) and Bluewater (reinforced with layers of both continuous strand and woven roving fiberglass). 

Given the structural properties of both materials, and how much of each we had left over from previous projects, we decided to laminate two pieces of HDU together to serve as the top of the hatch and use the Coosa Bluewater material for the sides of the hatch.

Our lazarette hatch is a trapezoid with the largest edge forward near the aft cabin. When building the Coosa frame, we opted to make the front edge taller than the trailing aft edge so that water would drain down the hatch rather than pool anywhere on top. We glued the edges together with Precision Board's HDU Adhesives, and used screws to hold the pieces together while the urethane adhesive set up. [Note: HDU and Coosa tend to move when the adhesive is applied, so clamps, screws, weights, etc. are needed to help keep the pieces in place.]

While the framing was setting up, we cut out two trapezoid pieces out of the HDU board --a larger piece to sit on top of the framing and one slightly smaller (1/2" on each side) to fit just inside the frame. The two trapezoids were laminated together, then glued and screwed to the Coosa frame.

Next it was time to test fit the new frame in spot. We installed Whitecap stainless hinges on all of our other hatches (excluding the butterfly hatch), so we checked those for placement with the hatch as well.

Whitecap Cast Stainless Hinges

Test fitting our new lazarette hatch made of Coosa Bluewater board and Sign Foam HDU board

We were then ready to remove all of the screws and prepare to fiberglass the hatch. We filled all of the screw holes with thickened epoxy, routered all of the edges, and laid down 20 ounces of woven fiberglass on the top and a 10 ounce layer on the inside as well.

Another design consideration for our hatch that we had to consider is that our rudder post is in the aft lazarette; in the event we need to use our emergency tiller, which attaches to the rudder post, we wanted to be able to install the emergency tiller without having the hatch completely open. Chances are you will only need the emergency tiller when the proverbial sh*t hits the fan, in which case, the decks are probably awash. Why add insult to injury and deal with water dumping down the hatch if you can avoid it?

To combat this issue, we decided to install a 4" access port to the hatch that we could open and insert the emergency tiller through if needed. We could also install a cowl vent in the port to allow airflow into the lazarette when running the generator. We measured for placement to align the emergency tiller with the rudder post and used a hole saw to cut the appropriately sized hole.

Lazarette hatch glassed and first coat of microballoons applied

Next, we used epoxy mixed with microballoons to fair the hatch smooth inside and out, sanding with an orbital sander between coats.

Fairing the lazarette hatch

When we were satisfied with the fairing, it was time for primer and gloss coats of paint. The entire hatch was primed inside and out, and we concentrated the finish gloss paint on the edges, around the access port, and inside of the hatch.

After allowing the gloss paint to cure for several days, we taped off the main top portion of the hatch, lightly scuffed the paint and applied the white Kiwigrip nonskid paint. We've been very happy with our Kiwigrip nonskid on Phoenix, and have used it both on the decks as well as in our nesting dinghy.

Gloss coat done and taping off for Kiwigrip non-skid application

Kiwigrip non-skid on Phoenix's lazarette hatch

Kiwigrip has a thick, yogurt-like consistency that is applied with a notched trowel, about 1/4" thick. You then use their "loopy-goopy" texture rollers to roll in the desired texture. Kiwi-grip dries pretty quickly -- usually touch dry in an hour, and can be walked in after 24 hours. Once the paint was dry, we installed the access hatch with stainless screws and butyl tape to make a watertight seal.

Access port installed and ready for install

I will be sewing a sleeve or boot to go around the emergency tiller to keep water from entering the hatch in the event we need to use it (probably out of neoprene). We don't really need to run the generator at this point, but we can pop in the cowl vent when necessary.

We now have a strong, walkable, low profile hatch on the aft deck that looks great! HDU and Coosa have really become our new favorite boat construction media. They are slightly more expensive than wood, but if you want to do the job once and never worry about rot or water penetration again, I would highly recommend working with them.

Pypilot Open-Source Marine Autopilot for Hydraulic Steering

With our Raspberry Pi (RPi) navigational computer up and running, it was time to turn our attention to compiling and installing a new autopilot.

Phoenix has hydraulic steering, specifically an older Wagner system. It has a large volume ram (33 cu. in; ~ 540 cc), which we rebuilt and installed new seals a few years back. We had all of the components of a rebuilt Wood-Freeman autopilot that matched what was originally on Phoenix ready to install, but decided we wanted to go in a different direction.

The Wood-Freeman systems are certainly powerful (they're still used on many commercial fishing boats in the Pacific Northwest, shrimp boats in Texas, etc.), but they are clunky, take up a ton of space (think bowling ball-sized compass versus quarter-sized 9-axis IMU chip in modern systems), and are power hungry. Fine for a fishing boat that's motoring all the time, but not ideal for a sailboat watching electrical power consumption. To top things off, we learned that they no longer made the seals for the specific Wood-Freeman hydraulic pump that came with Phoenix, and our decision was made for us!

Our friend Sean D'Epagnier developed an autopilot system that he tested on several ocean crossings -- pypilot --  and we began talking to him about how to scale up his design to work with our hydraulic system.

Pypilot is an open-source, RPi-based marine autopilot for tiller- and wheel-driven boats up to 40 feet.  The software is included in OpenPlotter, and was designed to work specifically with OpenCPN. The system is modular, has extremely low power consumption, and can be built and customized by the end user. Alternatively, you can purchase a tested system directly from the pypilot store if you don't want to do it yourself.

Like most autopilots, pypilot consists of an autopilot computer (brain) and a motor controller.

• The tinypilot computer is a WiFi enabled mini computer (RPi Zero) programmed with Sean's open-source pypilot software and with a 9-axis IMU chip or hat (3 axes of accelerometer data, 3 axes gyroscopic, and 3 axes magnetic (compass)). 
•  The motor controller is an arduino-based unit that connects to the pilot and controls the tiller, wheel, etc. It has over-temperature, over-current (stall) detection, fuse and reverse polarity protection, voltage, current, temperature and optional rudder feedback, and optional port/starboard end of travel input switches (rudder sensor) to prevent the tiller or wheel from going hard over.

The tinypilot would be at the core of our design; however his current motor controller design can only work with rudder drive units drawing 2-3 amps and stall up to 15 amp. We knew our system would draw more juice than that, so we needed a more powerful motor controller for our system. Before Sean could develop the new motor controller, we had to pick a hydraulic autopilot pump and figure out what our power draw would be.

Our 33 cu. in. Wagner ram is on the larger end for recreational boats, and we were surprised to learn that we had only two hydraulic reversing autopilot pumps to choose from -- the Simrad RPU300 and the Accu-Steer (Kobelt) HRP35 (sold under the Accu-Steer brand or private labeled by Furuno). From what we've read, the Simrad pump is quite loud, and some people said it sounded like copulating cats! The pump was going to be under the floorboards in the aft cabin and I'm a light sleeper so that was a deal breaker! The Accu-Steer, on the other hand, was touted as being "whisper quiet" and over-sized for our ram, so it was the clear winner. [Note: we found that searching online for Furuno HRP-35 proved significantly cheaper than searching for Accu-Steer HRP-35 even though they are the same part. The site we ordered from listed it as a Furuno pump and it was drop-shipped directly from Kobelt USA.]

Once the hydraulic pump arrived, Bill made a custom aluminum bracket to mount it under the floor boards in the aft cabin. I was thrilled with the new location since the old Wood-Freeman pump took out an entire large cabinet in the aft vanity -- more storage space freed up!

The pump is through-bolted through the bracket using four neoprene compression mounts (pillow blocks) to help dampen any vibration and make the "whisper quiet" pump even quieter. We went to a local hydraulic store for custom length hydraulic hoses with Aeroquip fittings to plumb the pump into our Wagner steering system and self-bleeding expansion/reservoir tank that Bill previously designed and installed. It was a messy job cracking open the hydraulic fluid-filled copper tubing and removing the old, clunky Wood-Freeman pump that was also full. We had to take be very careful since we didn't want to get hydraulic oil on our beloved cabin sole or screw up our tung oil finish! Once everything was apart, we took the opportunity to install a few more ball valves to help isolate the pump for any future maintenance or repairs.

Accu-Steer HRP-35 reversing hydraulic autopilot pump connected to pypilot aboard Phoenix

According to the manufacturers, the 12v HRP-35 could draw 10 amps continuous and 30 amps when the cylinder hit its end stops (hard over). To make sure that the new motor controller could easily handle the load, Sean designed our controller to handle up to 60 amps (momentarily) and built the arduino-based digital controller in an aluminum box with plenty of heat sinks. It is similar to his original motor controller in that drives the hydraulic motor while also monitoring voltage and current; however it is significantly more powerful and can handle a greater power load. We also added a temperature sensor to the hydraulic pump so we can monitor both the pump and motor controller temperatures.

Pypilot motor controller for larger boats like Phoenix

Our hydraulic pump is wired to the pypilot motor controller, which is also wired directly to the batteries (see bus bar in picture above). The white waterproof connector goes to the pypilot computer. In our case, it is a RPi Zero W with a 8 GB microSD card loaded with Sean's pypilot software, along with an AltIMU-10 v4 9-axis IMU chip in a waterproof box with a 12v power supply. We added a 30 amp inline fuse as both a circuit breaker and power supply switch.

30 amp waterproof inline fuse

Pypilot Marine Autopilot on Phoenix. The white box at top houses the computer and IMU chip, which is wired to the motor controller. A 30 amp inline fuse controls the power. The motor controller drives the hydraulic autopilot pump plumbed into a Wagner hydraulic system

Pypilot uses electric currents to determine the rudder angle, so in many cases a rudder angle indicator is optional. This is fine for a tiller or possibly cable-driven steering, but with hydraulic steering we felt the rudder angle indicator was required -- both to set appropriate end stops to prevent the ram from going hard over (possibly damaging the seals) and to offer rudder feedback information. We purchased a 12/24v rudder angle indicator sensor, which is essentially a stainless steel arm attached to a potentiometer. We also needed a pair of 6-32 ball links to attach the indicator to the rudder post.

Rudder angle sensor

The rudder angle indicator attaches to the rudder post parallel to the ram. Since our ram is particularly long, Bill had to thread a long aluminum rod to go between the indicator and rudder post. The indicator is then wired from the indicator to the pypilot computer.

With all of the hardware in place, it was time to fire up the pypilot along with our navigational computer running OpenPlotter and OpenCPN. We'll call it the NavPi. As I mentioned in our previous post, we wanted to be able to see and control the autopilot and view all of our data at the nav station as well as in the cockpit using a Windows-based touchscreen tablet.

Pypilot functions as a WiFi access point (AP), and OpenPlotter can function as either an AP or as a client. In order to accomplish our goals, we have the pypilot set up as the AP and OpenPlotter set up as the client. When both are powered on, NavPi connects to the pypilot over the wireless connection. It receives rudder feedback information and controls the autopilot. The pypilot receives the wind, GPS, and other NMEA sentences transmitted from the NavPi. We can engage or disengage the autopilot, steer via compass, GPS, or wind (true or apparent) by clicking buttons in an OpenCPN plugin or app from the nav station.

When we boot up the tablet, it also connects to the pypilot over the wireless connection. Once we open OpenCPN on the tablet, it receives depth, speed, wind, GPS, AIS, rudder angle, pitch, heel, barometric pressure, temperatures, etc. from the two RPi computers down below and can also control the autopilot.

Once fired up, we had to calibrate the IMU and the rudder indicator. When the boat is level, go to the calibration page and set the pitch/heel angle by telling the software the boat is level.

Pypilot -- calibrating pitch and heel

The compass will calibrate while the boat is moving. For initial calibration, steer the boat in a 360 to allow it to collect enough data points for calibration (for us, we had enough points backing out of our slip, then turning to point into the wind to raise the main).

Pypilot compass calibration needs to be done

Pypilot compass calibration is complete and data points are located on the sphere

We also had to calibrate the rudder indicator and set the end stops. We centered the rudder and established 0 degrees, and also the end stops to prevent the rudder from going hard over. You can also establish fail safes to turn the autopilot off if the motor gets to a certain temperature, max current, etc.

Sample screenshot of pypilot plugin in OpenCPN -- from OpenPlotter Manual.

We went on a few test sails with Sean while he was visiting to test the system and work out any bugs. Sean made a video of one of our test sails.

Sean D'Epagnier remotely steering Phoenix using his pypilot marine autopilot

Since then, we spent a considerable amount of time sailing the Chesapeake and testing the autopilot on our own. The most impressive aspect that we can report to date is how efficient the autopilot is and how little power it consumes while steering true.

In our first trip out, we ran the pypilot for nearly 3 hours and used a miserly 1.2 amp hours! By comparison, most commercial autopilots will use 6+ amps per hour.

Pypilot uses remarkably little power when sailing upwind or on a beam reach, and we can run it for 10-12 hours in GPS mode and use 6 amp hours or less.

As expected, the power consumption varies with different sailing conditions, as well as with how well your sails are trimmed. We found we used the most power to date sailing on a deep broad reach (120-150 degrees), jib and jigger with a 4' following sea. Over an 8 hour run it used 9 amp hours. As soon as the waves subsided the power consumption decreased, and neither the motor controller nor the pump showed signs of overheating.

On a similar broad reach using the main and genoa, we used 6 amp hours over a 10 hour period.

Thus far, pypilot holds course very well in GPS and compass modes. Steering to wind is not the systems strong suit, though playing with the gains and sail trim does help somewhat. Sean is continually updating the software and is very responsive to questions people may have about his system. He is also continually updating information in his his online wiki "manual".

The biggest challenge in using the pypilot to date is getting used to the variety of gain settings to maximize efficiency, which we are still learning. There are almost too many parameters to play with! But the more we play with the pypilot the more we love having our new 3rd crew member on board!

Bill kicking back and letting the pypilot autopilot do all the work!

The pypilot was particularly helpful when we were trolling while sailing on a beam reach at 7 knots and had two fish on at once! The autopilot definitely did its part in filling the fridge (and our bellies) that day!

Catching Spanish Mackerel aboard Phoenix

If you are looking for a new autopilot, or to reduce the power consumption you use while running the autopilot, I would seriously consider looking into the pypilot. It does everything a commercial autopilot can do at a small fraction of the price and energy load.

Sean is very passionate about creating open source software that people can use and customize to their specifications. We had the opportunity to see Sean build, program, and make improvements to the pypilot system while he was working on ours and were impressed with the amount of time, attention to detail, and quality control he puts into each one. Although you could certainly build a pypilot from source yourself, purchasing a system built and tested by the creator at a low cost is a bargain and made a lot of sense to us. Plus, you get to help a fellow sailor continue to make cutting edge technology for all of us to use!