Electric Motoring

When you decide you want to crank up your electric motor to reach a destination, there are some important steps to follow.

First, you should understand how to read the display from the electric motor.

The display is organized into two columns. The left column shows: Battery voltage (V), Engine power production (KW), Time remaining at current draw rate (HR). The right column shows: Motor consumption in Amps (A), Battery charge remaining (%), and Propeller RPM (R/M).

In this example, the battery has 47.97 volts DC, the motor is drawing 121 amps, producing 5.82 KW, 88% battery remaining, making the propeller spin at 1121 RPM, and has a remaining run time of 1.2 hours.

The reason this is important is if you are trying to motor somewhere, this information will be very important in determining if you will make it or not. A good chart plotter with navigational functions can provide you with an ETA to your destination. The ETA is your Estimated Time of Arrival. If your ETA is longer than your remaining battery run time (lower left corner), you are not going to make it at your current speed. 

At higher speeds, you will have less run time because the engine will be drawing more amps to move your vessel. Slower speeds will provide more run time, but it will also take you longer to get anywhere. On Wisdom, we can travel at full throttle (7.5 knots) for 24 minutes. This will give us a range of 3 nautical miles. At 2 knots, we consume around 10 amps and have a run time of around 20 hours, giving us a range of 40 nautical miles.

As you can see, moving slower will give you more range, but it will also take you forever to get there. This is why I use the ETA readout on the chart plotter in combination with the remaining run time in the lower left corner to find a speed that will get us to our destination with at least an hour of run time remaining. This extra hour will provide us with some buffer to changes in weather or currents, and avoid a complete discharge of our engine battery bank (which would destroy the batteries). 

Solar Panel Wiring

Now that the solar panels are perched to collect the suns solar energy, it is time to write the system up and feed our electrical needs. 

I ran the wires from the panels to the battery switch, and then let my friend Bob Blood do the electrical connections. Bob Blood is an ABYC certified electrician and does gorgeous work that lasts! 

The solar panels lead to the charge controllers, which then feed the battery banks. These charge controllers are by Genasun and are significantly less expensive than other brands. They are made in the USA and have a reputation for being work horses, but they don't have the fancy display screens of other brands.  

Instead they have a single LED light that blinks. Slow, for ready; fast, for charging; stay, for charged; red, for fault. 

The solar panels are able to feed the house bank (315 amp hours and 12V DC) as well as the electric motor bank (210 amp hours and 48V DC).

The electric motor produces its own power while we sail, up to 4 amps at 48V DC! When we need to charge up the motor bank, we simply sail on a beam reach and bring up its charge! 

The solar panels are the equivalent of a trickle charge for the motor bank, but they can help float the batteries while at anchor for a long time.  

On the house side of our electrical system, the biggest consumer is our fridge. The fridge is 14.5 cubic feet with a freezer section and consumes a lot of amps! With the solar panels off, the house bank will drop to 11V when the refrigerator compressor turns on. With the solar panels on, the voltage stays at 12.3V with the fridge on and 13.3V with the fridge off (in between compressor cycles).

While we only have 100W of solar panels (at 12V DC), we also only have meager electrical needs. Our cabin lights and running lights are LED, and don't consume much electricity at all. Our other electrical needs are to power a small garmin chart plotter, depth sounder, and VHF radio. The only big consumer is our massive refrigerator. 

By keeping the systems in the boat simple, we are also able to keep our demands low, which allows us to spend less money on solar panels to power these electrical conveniences. 

Advantages of Electric Motor vs Diesel

Electric motor manufacturers state many advantages over diesels.

They have less moving parts to break
They don't smell
They don't pollute
They are smaller
They don't use fuel
They are quieter

These things are all true, but I don't think they get the point across of just how different they are from diesel engines. 

I used to fix my diesel engine every time it died, which was almost every time I went sailing. I spent plenty of time bleeding the injectors, adjusting the valves, changing impellers and filters, and clearing debris from the strainers. It usually died when I was docking and would throw it in reverse to slow me down as I came into my slip. I was so fed up with the diesel that I decided to pull it out and be completely engineless. Maddie quickly asked:

"If we were sailing along and came across a marina in unfavorable conditions, how would we dock?"

My answer of "we don't" was not well received. For this reason, we decided on an electric motor to get us in and out of marinas. While we chose a very small battery bank, just enough to get us in and out of marinas, a properly sized battery bank would allow for a much longer motoring range. If you combine a larger battery bank with a generator, you can extend your range even further yet! But we prefer to sail, so we went with as small of a battery bank as we could.

The more parts involved, the more parts available to fail, and the more times the diesel won't work perfectly. This combined with the fact that sailboats mistreat their diesels in horrible ways. Diesels are meant to be turned on, warmed up and then run under a load for hours before being shut down. Sailboats turn them on to leave the marina (not much load or run time) and then shut them down. Then the occasional start up to get out of the way of a cargo ship or to charge the batteries, neither of them offer the run time nor the load a diesel needs to survive. 

They have less moving parts to break

Electric motors have a 1 moving part, the output shaft. Electric motors are made up of three main parts, a Rotor (output shaft) which is permanently attached to a Stator, so they move as one piece. The last main component of the motor is the Windings, which also do not move. There are no parts that burn, grind, or wear out like a diesel motor has. They work because of physics! Electro-magnetism will always make the rotor spin without any parts actually touching each other. The motor works because an electric field is applied to the windings which causes the stator and rotor assembly to spin, which spins the propeller. There is no transmission, or fuel pump, or injectors to complicate the system, it simply works when you need it on demand!

When the diesel would fail to run, I would have to figure out what the problem was this time. When the electric would fail to run, it was because I forgot to turn it on.

From a smell stand point, electric motors are worlds apart. If you have a diesel engine and want to know what it would smell like with an electric motor, all you have to do is anchor out in a quiet creek, far removed from civilization where the birds are flying around in the calm fresh breeze. Take a good sniff, that is what it could smell like inside your cabin!

Diesel motors pollute, and there is no nice way around it. As many filters and systems (which complicate the motor) that they add, you still can't stand next to a running diesel engine in a closed room. The exhaust will make you feel ill in a few minutes and then kill you shortly after that. It is perfectly safe to be in a closed room with a running electric motor. 

When you picture the serenity of a sailboat gliding through the water, you don't associate it with the large black plume of exhaust smoke that accompanies a diesel engine.

Please start video at 1:25

Electric motors don't have an exhaust pipe, because they don't have any toxic exhaust that needs to be shunted outside. The simply spin along quietly in their little space, quietly turning the propeller.

On the note of space, the size difference is insane! My old diesel motor weighed over 700lbs and produced 30hp at full throttle. It also occupied the entire space under the galley, nav station, and companionway. The electric fits in the space of the old transmission and weighs only 135lbs, producing 27hp (20kW). 

The Bottom square holds the engine
The Second square holds the transmission
The Third square holds the shaft
The Fourth square holds the packing gland

This is the Transmission square from the previous picture. It holds the entire engine assembly.

Electric motors do not consume fossil fuels. I have talked with other cruisers about budgeting and average expenditures while cruising. They all have a rather large portion that gets burned up in fuel. One couple said they use around $400 a month in fuel, another solo sailor uses $750 a month in fuel! When we did our trip for a month, we never even thought about fuel costs. We budgeted for food and excursions in the places we sailed to. The three marinas we stopped in let us plug in to recharge our batteries, costing us $4 in electric per day. This electric also ran our fridge and air conditioner, but the total cost for our electric hook ups in the month ran $24. While under sail, the propeller would spin and recharge the battery bank (regeneration). When we sailed at 7 knots, we were able to produce 200W! Comparing our month to those cruisers, we had an extra $400 to $750 a month for excursions and on-shore dinners.

The best part of an electric motor is the silence! When you are in neutral, the propeller isn't spinning and neither is the motor; resulting in complete silence. When you are in forward or reverse, the motor is turning silently and the propeller slices through the water. When you apply a lot of throttle, the propeller will begin to cavitate and make propeller noise. The first time I put the boat in full speed ahead, I heard the prop noise and was startled. I never heard my own prop noise because of the loud clunking diesel. For the sake of silence, I try to keep prop speed down to just below cavitation speed, that way the motor makes no noise and neither does the propeller.

The biggest difference in the quality of boating offered by the electric motor is the peace on board when you need mechanical propulsion. We liveaboard with our parrot (Sammy) and our dog (Morty). Sammy would scream and screech with terror whenever the diesel would be turned on. There was no sound insulation, so the floors would rattle as the large clunker banged away underfoot. The floor boards would become hot, and it would hurt your ears to be in the cabin with the engine running. Morty would panic and start barking at the noise, running around trying to find the source of this noise! This horrible noise is what made me the sailor I am. I hated running the motor and refused to run it any more than necessary. I loved the peace so much and couldn't bring myself to crank on the noisy smelly monster. I would sail in and out of every creek and river on the bay. When there was no wind, I would rather sit than listen to the diesel. If I did have to motor any great distance, I would bring my parrot and dog into the cockpit and close up the cabin to try and keep the noise down to a tolerable level. It was such a hassle which is what made the electric motor seem like such a blessing. 

It runs quietly, smoothly, and with no smoke or screaming pets. When we have needed to motor, Sammy the parrot is content in her cage in the salon, and Morty the dog continues to sleep peacefully. 

If we get caught in irons, we can give the motor a boost of throttle to get us through the tack. When a cargo ship sneaks up on us, we can quickly power out of his way. We can easily flip a switch to turn the engine on, give it throttle, and then turn it right off without any worry about hurting the diesel. 

If you are thinking of going engineless, do consider a small electric motor. They can prove to be a very handy tool while out sailing. They can provide the mechanical propulsion needed in an instant when getting an oar set up or getting a pushboat ready is not feasible without all the negatives associated with a motor while cruising.

Summer Cruise Day 16.5

Once we were reefed, we made our way towards the mouth of the bay. We were sailing as close to the wind as we could with the current sea state. As the wind shifted, we were not able to clear the point of land just north of Virginia Beach. We came close to shore and were going to tack when the winds shifted again. We needed to pinch for a few miles but we would be able to make it around the point with 1 mile of sea way between us and shallow water. 

I didn't want to tack because that would add several hours to our arrival time. This is usually not an issue, but the mouth of the bay is subject to very strong currents. If we would be able to make it in time, we would be swept in by a several knot current. If we tacked, we would arrive later and be fighting the current, in the dark, in a very busy shipping channel. I suggested that we set out back to sea but Maddie wanted to be back in the bay today, so we continued on. 

As the winds were, we would arrive to the point in 1.5 hours, which would put us in the strong current flooding the bay. We were rather close to shore and got a wonderful view of the crowded beach.

Being very close to the naval base at Norfolk, VA, we were passed by many naval boats. A fleet of 3 black speed boats flew past us in formation. Later a submarine went by us as he headed out for deeper waters. The submarine moved quietly through the water but created a monster wake! The submarine wake was on par with a tug boat moving at hull speed. I wonder if they create a wake when submerged?

As we neared the point, the winds began to die, but we were still able to maintain movement through the water. At this new pace, we would catch the tail end of the flood tide, so while not ideal, we would still make it in today. 

We rounded the point of Virginia Beach and the winds died completely! We switched the jib for the drifter, but there wasn't even enough air to fill it. We sat still as the current slowly pushed us into the mouth of the bay.

As we sat nearly stationary in the water, pelicans began flying near by. Maddie got a bunch of pictures with the intention of painting pelicans next in her series of bird paintings.

The tide began to slow and the winds had not returned yet. I was worried that we would soon be swept out to sea and lay drifting near the busy channel during the night. I began looking at places to go once we made it into the bay, preferably a marina where we could recharge the motor battery since I was about to drain it down getting into the bay. We found one on the charts and I called them, they had a slip waiting for us and we could arrive after dark. 

I entered their location on the chart plotter and that gave us an ETA. Then I turned on the motor and set the engine speed so that we would have enough run time to make it to the marina and with 1 hour of battery time left. 

As time went on, the tide was going to begin ebbing, and we would begin fighting the current. I decided to push it harder and figure it out once we made it into the bay or else we would run out of battery while fighting the current. We pushed and made it in past the bridge's channel, then turned to port. Luckily, there was a tiny bit of wind directly behind us and we were able to sail wing on wing with the main and drifter. 

We sailed along at 1.5 to 2 knots, nothing fast, but at least we were moving. 

We found a buoy marking the entrance to the channel and we turned in. It was dark, the sun had set hours ago by this point and we were ready to sleep in a protected marina. We sailed down the channel which was teeming with power boats, even at this late hour.

We encountered the blinding lights of the naval yard so I had Maddie go forward to make sure we were not going to hit anything. Out of the darkness we saw a large log float. I thought it was a mooring ball for the navy, but it turns out that it was a log boom separating the civilian marina from the naval yard. I steered to avoid the log and took us straight into the naval base.

Search lights focused on us and a Zodiac came over to question us. They were understanding enough and let us tack out of their side to head over to the marina. Apparently, many people come into the naval yard looking for the marina.

After a series of tacks, we made it out of the naval base and found our marina, and our slip. We were nestled in behind a very large catamaran, tied up, and plugged in to recharge the very exhausted engine batteries. We burned them all the way down to 16% trying to get into the bay against the current. 

 

We went ashore to find the only restaurant open at this hour for a land cooked meal, followed by a very deep sleep! I miss the ocean, but it's nice to keep the admiral happy too!

Summer Cruise Day 9

Today began with raising anchor in the wee hours of the morning and settingall the sails as we made our way South. 

We were sailing in relatively light airs, so we had the drifter flying. At times, we were barely moving, then we would be charging along making wonderful progress.  

For long periods of time, we were sailing along between 6 to 7 knots, and the electric motor was able to recharge the batteries the whole time.  

Our fridge is the biggest consumer of amps on the boat. When drawing off of the engine bank of 8 group 31 batteries, it will consume about 10% of the bank over the night. A few days of this and the batteries begin to run low. This is why fast sailing days are so highly appreciated on board Wisdom. The motor acting as a hydrogenerator is our only method of recharging.  

That morning, we gained nearly 30% in the engine battery bank! The equivalent of 3 nights of running the fridge. This was all possible thanks to the drifter that was able to power us along on such a light air days. 

As the day grew on, the winds began to build. When the winds were sustained around 10 knots, we decided to drop the drifter and raise the jib to continue our journey South.  This was also the end of our progression for the next few days, we just didn't know it yet. 

I released the halyard and lowered the drifter, but didn't pay any attention to the sheets. The port sheet fouled the prop and our speed decreased from 6 knots to a mere 3 knots.  

We decided to get away from the ship traffic along the western shore and head over to the eastern shore to sort out the issue.  

The wind continued to build and we sailed across the bay with 1 reef in and the stay sail in winds of 20 to 25 knots while moving along at barely 3 to 4 knots.  

We dropped the anchor on a shoal and I got into our dinghy "Tooth" to try and free the fouled line. In my optimism, I figured that the line was merely looped around a blade and then wrapped around the propeller. I figured it would just as easily come free.  

I spent two hours fighting with the line trying to free it, but to no avail. It was a calm sunset on the bay in unprotected waters. I called Boat US to schedule a tow in the morning.  

I was to be towed to Deltaville marina to be hauled out and to free the prop from the fouled line.  

We settled in and rested up as we had no idea the drama that the morning would bring.