Best Drones for Cruising

Drones are awesome, there is no denying it. They can get to the perfect vantage point, and we all love the drone footage in our favorite YouTube videos! While drones may seem awesome at first, sailing with one may feel a little different.

Being a cruising YouTuber has it’s perks, first you get to meet other cruising YouTube channels and compare notes on different camera gear and techniques. The second perk is your toys will pay for themselves because the videos you make with these toys produce revenue.

But, as always, life isn’t always as easy as it may seem, and sailing with a drone can be a hazard (to the drone). There are a few important points that should be considered when looking at a drone for cruising with. First is size, then capabilities, then price.

DJI Phantom

Drones are often barely seen up in the sky, but when you get up close to them, you begin to notice how big they really are. Big, is never a good thing when you need to stow it safely in a sailboat!

One of the most famous drones, the DJI Phantom, is HUGE! Yes, it has incredible range, films in 4K, and flies at blazing speeds, it is still really big.

Our friends Jessica and Ryan from Jessica and Ryan Adventures have this drone and we got to see it in action first hand. It was amazing!

They would launch it and send it high up into the sky where they would get amazing images of the entire anchorage they were in. They could also fly it around the neighboring islands to see what looks like the best place to go explore by dinghy. It served as more of a reconnaissance aircraft to scout out hidden gems in the islands, and it did this task beautifully!

The drone flight sequence starts at around 4:50 seconds. This drone is fast, and the images it captures are unreal. How else could you get an effortless birds eye view?

So we know that this is the drone that most YouTubers use because it gets the best video from the most powerful drone! But what happens when you are not flying the drone? What happens for the other 99.9999% of the life of the drone when it is NOT flying?

Well it takes up space! Being a big drone, it takes up a lot of space. The body of the drone is larger than a square foot, and the propellers extend making it even bigger. The powerful propellers do not fold, so unless you remove them, it’s going to take up a lot of space.

That being said, if you have the space a budget for a Phantom, go for it! Our friends, Jessica and Ryan have a catamaran, giving them plenty of space to store the drone on a flat surface without fear of the surface tilting while under sail and the drone falling off. If you have an old monohull like we do, maybe think about this purchase a little harder.

All drones have a specially built carrying case, and the phantom is no different, but the phantom’s carrying case looks like a carry-on bag for a flight.

DJI Mavic

The next step down in size is the DJI Mavic. This drone offers similar performance to the Phantom, but in a more “travel friendly” package. The controller is smaller, the drone is smaller, and the drone also folds to make it stow tighter. To round up the whole “smaller package” concept, it’s carrying case is a backpack.

It still offers 4K video, almost a half hour of flight time, and a 3 axis gimbal for the camera, just like the phantom, but in a folding package that can stow more easily in a space limiting environment, like in a sailboat.

This gives you a nice compromise between space and performance, saving you a bit of space while only reducing the performance a slight amount.

DJI Spark

Now, if space and price are both limited, welcome to the smallest and cheapest of the “good” drones: the Spark.

This is the drone we went with, as it is tiny! The Spark is the size of a cell phone, and the propeller fold up to make it stow neatly in a tiny bag smaller than a purse.

This lets it safely live in a padded and protective bag, in our closet (while at sea) or on our navigation station next to the radio on a small shelf (while in port).

So, what are you sacrificing with the Spark to get the tiny size? A few things.

It won’t shoot in 4K, only up to 1080p. It won’t fly for a half hour, only about 12-15 minutes (depending on how fast you want to fly and how windy it is where you are flying), and it won’t fly as fast (6-8 mph in normal mode, low 20s mph in sport mode). Oh, and you are also giving up on the high price tag!

This was one of the biggest points that we considered when we bought our drone! We know the salt air is going to kill the drone. We also know that one day it might fall into the water and die! Losing a drone sucks, but it would suck a lot more if it was almost $1000 that went in the water!

When we bought our Spark, we inquired about the replacement cost of “just the drone”. Not the controller, and the case, and all the other parts that come in the kit, and we were very pleased to hear that it was only around $300. With this wonderful knowledge, we decided to upgrade our YouTube channel with the purchase of our new drone, the DJI Spark!

It fits in our narrow old monohull that we are sailing around the Atlantic without taking up too much space, and it gets great shots from the air! Yes, the flight time is rather short, but this just means that you need to plan your flight before you turn it on. We typically have an idea in mind, send the drone up, capture it, and then bring it back down. Having two batteries means we can do this multiple times on hikes and excursions.

Sadly, video editing is a long process, and the shots with the drone haven’t been reached yet at the time of this blog post (we started flying our drone when we made it to Horta, Azores), but in the channel trailer, at the very end, there is a drone clip filmed with the DJI Spark.

Drones are awesome, and they can take your cruising to a whole new level by showing you where you are from an entirely new perspective. We get used to thinking that sea level is the only way to view new anchorages, but a drone will show you the majestic and magical place you are anchored in, making you appreciate it all the greater!

Electric Motor Regen

It seems that little is ever truly discussed about regenerative capabilities (or regen) of an electric motor on a yacht. Those who don’t have electric motors often tout that regen is fictitious and doesn’t actually produce any usable power, while those with electric motors seem to keep quiet about it.

I wish to break that silence and go into the details of regen and what it can actually do.

Regen occurs when you are sailing and the force of the water over the propeller causes the propeller to spin. Since the propeller is connected to the motor, the motor will also spin. With a small electrical current supplied to the motor, the magnets in the motor will begin to act as a generator and produce power that will feed back into the battery bank. This process can add a lot of power to your batteries, giving you more range under power later while also supplying power to run your yachts electrical systems.

But how does it do this and how does regen work exactly? Regeneration is the transformation of kinetic energy into electrical energy. This takes work to accomplish, and leverage really helps here.

The magnet inside the electric motor is resisting movement thanks to the electromagnetic field created by supplying a small amount of electricity to the wires that are wound up around the motor. To make the magnet spin, you need enough torque on the shaft (work supplied by the propeller) to overpower the force of the electric field and cause the magnet to rotate. You also need the magnet to spin quickly to pull the electrons in the field around fast enough to create a flow of electricity. So, you need fast spinning and you need lots of torque.

As you can imagine, it all comes down to the propeller, as this is the structure that is going to create the spin and supply the needed torque to the motor. The more blades your propeller has, the more effective it will be at being turned by passing water. Also, the longer the blades are (larger diameter of the propeller), the more torque can be generated.

Imagine that you are trying to change a tire and the lug nuts just wont budge. You are faced with two options: get stronger or get a longer wrench.

Getting stronger will apply more force to the same wrench which will then supply enough torque to the suborn lug nut and remove it. This is the equivalent to sailing faster to cause more water to rush by the propeller and force it to spin.

Getting a longer wrench allows you to multiply your force thanks to leverage which will supply more torque to the stubborn lug nut while you are still applying the same amount of force on the wrench. This is the concept behind “foot pounds”. If you hang 1 pound from a 1 foot wrench, you would be exerting 1 foot pound on that stubborn lug nut. But if you hang that same 1 pound from a 2 foot wrench, you would now be exerting 2 foot pounds on that same lug nut!

Having a larger diameter propeller means that the force of the water at the tips of the propeller blades will have much more leverage and will generate much more torque. This will allow you to spin the magnet in the motor with more torque which will in turn generate much more power than if you had a small propeller which supplied much less torque.

Sadly, due to clearance issues, it is impossible to simply “make the propeller huge” on a yacht, as you are limited by the space and clearance of the hull structures around your propeller.

It seems that the minimum propeller size to generate any appreciable regen is 16 inches. Larger propellers produce more torque and therefore can generate much more regen power, while smaller propellers don’t seem to have enough torque to overcome the electromagnetic field of the motor and generate sufficient amounts of power.

This is where the bad reputation gets further muddied. Smaller yachts that are used as day sailors tend to also have small propellers, so they are not being used for long enough distances and have propellers that are too small for the task at hand. Larger yachts have larger propellers and are often cruised over long distances. There are many more day sailors than there are blue water cruisers, so the number of stories of “it doesn’t work” vs “it works great” gets skewed.

I feel the best way to look at regen is not to view it as instant power being added back into your batteries, but more in the view of power that can be harvested over a distance that is sailed. Regen needs a few key ingredients to work, you need a large propeller with many blades and you need speed. We are equipped with a 16 inch diameter three blade propeller, which apparently is the smallest size and number of blades to get any appreciable regen from, and are able to generate around 2 amps @48v while sailing at 5 knots, and 6 amps @48v when sailing at 6 to 7 knots. We never seem to sustain speeds of 8 or 9 knots for a long enough time to retrieve the really high amps that are being produced, so for all intents and purposes, I ignore them.  If we are sailing at speeds less than 5 knots, regen is insignificant and we actually turn the system off so that the propeller can free wheel without slowing us down much. 

So, imagine that we are sailing along at 5 knots and producing 2 amps @48v. This means that in 1 hour, we would have sailed 5 nautical miles and generated 2 amps @48v. If we sail at this speed for 10 hours, we would cover 50 nautical miles and generate 20 amps @48v (or 80 amps @12v). At the same time, if we managed to sail at 7 knot for that same distance, you would only sail for 7.1 hours but have produced 42.8 amps @48v (or 171.2 amps @12v) in that same distance! As you move faster through the water, you will spin the propeller more quickly and that will generate much more power; but you do have to sail the distance to extract the power for your batteries. 

Nighttime photo of motor display while sailing between 6 and 7 knots.

In the display above, you can see that it is producing 6.0 amps at 51.22 volts DC, and 0.30 kilowatts because the motor is spinning at 247 revolutions per minute.

What this all means is that our electric motor is producing 300 watts of power and that power is being fed back into our batteries. 6 amps might not sound like much, but this is in a 48 volt system. When the power is stepped down to 12 volts to power the yachts electrical systems, those 6 amps are the equivalent of 24 amps in 12 volt!

Suddenly, the tiny electric motor is producing the same amount of power as three 100 watt solar panels, but this is occurring all the time! It can be high noon on a cloudy day, or in the middle of the night, the motor will produce this kind of power when you are sailing through the water with enough speed to turn the propeller.

So, why is regen not typically talked about? Well, the numbers are not representative of what you are getting at every single moment, but more of what you could get in an hour. People like instant results and don’t want to wait around for it, but they don’t seem to realize that they have to wait for everything anyways. Solar panels take hours to charge batteries, and so do generators, but these are things that people usually set and forget. Regen requires the boat to constantly remain in motion and if your speed falters, so will your power production. If you are hand steering, then you are going to have to work for that power! If you have a balanced sail plan and wind steering, then it becomes just as passive as your solar panels, wind gen, or genset.

In this example, 300 watts added to the battery bank would only be there after a full hour at this speed. If you are puttering around for a few hours, 300 watts per hour might not add up to anything appreciable, which is why regen has gotten a bad reputation. When you are passage making and sailing around the clock for days, these numbers become very real and very important.

Hour: Watts / Amps @12v / Amps at 48v

1: 300W / 24 amps / 6 amps

2: 600W / 48 amps / 12 amps

3: 900W / 72 amps / 18 amps

4: 1200W / 96 amps / 24 amps

5: 1500W / 120 amps / 30 amps

6: 1800W / 144 amps / 36 amps

7: 2100W / 168 amps / 42 amps

8: 2400W / 192 amps / 48 amps

9: 2700W / 216 amps / 54 amps

10: 3000W / 240 amps / 60 amps

11: 3300W / 264 amps / 66 amps

12: 3600W / 288 amps / 72 amps

13: 3900W / 312 amps / 78 amps

14: 4200W / 336 amps / 84 amps

15: 4500w / 360 amps / 90 amps

16: 4800W / 384 amps / 96 amps

17: 5100W / 408 amps / 102 amps

18: 5400W / 432 amps / 108 amps

19: 5700W / 456 amps / 114 amps

20: 6000W / 480 amps / 120 amps

21: 6300W / 504 amps / 126 amps

22: 6600W / 528 amps / 132 amps

23: 6900W / 552 amps / 138 amps

24: 7200W / 576 amps / 144 amps

300 watts per hour tallies up in the table.

What this means is that if you only sail at 6 to 7 knots for a few hours, you will only gain a few hundred watts, just the same as you would produce from a 300W solar array in peak sunlight hours. This will give you a few watts to play with here and there but probably nothing you would really notice.

If you go out for a daysail and plan on having the regen charge you back up to bring you back into port, but you only sailed for 2 hours, you can only expect to see up to 12 additional amps in your motor battery bank if you managed to sail at speeds over 6 knots for the entire time. This is really insignificant and probably where the bad reputation comes from.

When you are sailing a long distance, and are under sail at speeds over 6 knots for around 12 hours, you could expect to see up to an extra 72 amps in your motor bank! This is a significant amount and will provide you with the power needed to bring your yacht back into port with ease.

When we were crossing the ocean, we were sailing for days (almost a month actually) and we had full batteries the entire way!

Our motor bank is 210 amp hours @ 48 volts and our house bank is 525 amp hours @ 12 volts.

If we left port with completely empty batteries (which was not the case) we would have been able to charge the house bank fully in 22 hours, and have the motor bank completely charged in the next 35 hours! This means that in 57 hours, we could fully charge all of our batteries without using a single drop of fossil fuels; just by sailing fast!

In our case, we actually left with full batteries, but all of our electronics needed lots of power on the crossing, and they were all supplied completely by the regen of the electric motor.

Now, not all electric motors have regen, so it is imperative that you make sure the one you are looking at does. Our electric motor is a QT20 (Quiet Torque 20kw) from Electric Yachts

This motor is a plug and play design, allowing you to have all the benefits of a well engineered system that simply drops into your boat. It gives you all the information you need to properly operate it while maximizing your range and motoring time. It also has a very simple user interface to set the regen level you desire. When we were looking for which type of electric motor to use, we noticed that many of them had complicated procedures to regen, and some of them could easily begin to draw power if you were not paying close attention! This one is pretty much fool proof, as regen occurs when the throttle lever is in the neutral position and power consumption occurs when you move the throttle lever forwards or backwards.

Regen is a truly remarkable feature of an electric motor which I feel makes it the best motor to have for blue water passage making. If you are a coastal cruiser who only does short trips, regen might not be very apparent to you, but the moment you head out on your first long leg, regen can keep you charged up.

Light Houses

Light houses are a beacon of civilization on a dark and lonely ocean. They make great tourist attractions and are often listed in tour guides, but this is only when they are viewed from land.

At sea, light houses carry a different meaning. They are a beacon of danger. They are usually perched on the edge of a cliff signaling the presence of dangerous rocks.

The color of a light house light can vary as well. White simply means that you are being warned of the danger where they are located. Yellow and Red indicate danger, and when you see that color, it means you are in harms way and need to move out to sea in a hurry!

While they stand to identify danger, they also signify the presence of human civilization. When you have been out at sea for weeks on end, seeing the flashing light of a light house will tell you that you have found your new land, and which direction to go to get to shore. You have been alone for so long, and suddenly, you are being guided towards humanity. You will no longer be alone, you will no longer be tossed around, you will soon arrive!

Upgrading to Lithium Batteries, Battle Born vs. Renogy

Electric motors are great, they have few moving parts to maintain or fail, and they can run effortlessly forever…or until the power runs out!

The heart of an electric setup is not the motor, but actually the batteries. These boxes of energy house the electricity that the electric motor needs to propel your yacht. The more power you can carry in your batteries, the more power you can use with your motor.

When we did our conversion to electric propulsion back in 2014, we chose AGM batteries, simply because they were the most cost effective at the time. They provided us with a lot of power in a large space and required little maintenance.

Fast forward to the present, and our AGMs are old and outdated. Better battery technology has come down in price and the “better batteries” of 2014 are no longer prohibitively expensive.

At the moment, there are two companies that seem to be reigning as king over the “direct replacement” lithium batteries. These companies sell lithium batteries that are the same size as the more popular lead acid and AGM batteries, but at a fraction of the weight.

The first company is Battle Born

Source: https://amzn.to/2TfdpoP

These batteries are the same size as a Group 27, but contain the power of a Group 31. Moreover, they only weigh 31 pounds! Our current AGMs are Group 31 and weigh 67 pounds each, meaning these batteries weigh less than half of what our batteries weigh.

The next battery company that we will look at is Renogy.

Source: https://amzn.to/2TgtLO3

Renogy Batteries are also direct replacements for lead acid and AGM batteries, but these are even lighter in weight! Their 100ah battery weighs in at only 28 pounds!

Now that we know the major players in “direct replacement” batteries, lets look at why they are more sought after than a regular lithium battery. The first thing is familiarity. For our entire lives, batteries have been this rectangular box that sits in our boat or car and has two terminals on it. Lithium batteries can come in a huge variety of shapes and sizes, which sadly leads to people wondering “which side is the top?” Direct replacement batteries do away with this metal block to lithium by packing it into a familiar shape and size.

The second advantage comes with the voltage. Lithium batteries are made up of cells, and the entire battery pack can have any voltage value you want! This once again becomes a problem since people are used to a battery being 12 volt. In our case where we run a 48v motor, we simply have four 12 volt batteries hooked up in series to create the 48 volts we need to operate. Instead of Battle Born and Renogy offering their batteries in “custom voltages” they packaged them as 12 volt batteries.

You might be wondering, why switch to lithium at all if they take up practically the same space and give you the same amount of power? There are two answers to this question. The first is weight, and the second is usable power.

Lithium batteries weigh less than half of a regular battery. The best way to visualize this is to look at the Amps per Pound at 12 volts.

AGM batteries hold 105 amp hours and weigh 67 pounds
This is to say 1.567 amps per pound

If you want to have a 800 amp hour battery bank, it will weigh (800/1.567) 510.5 pounds.

Battle Born batteries hold 100 amps and weigh 31 pounds.
This is to say 3.225 amps per pound

That same 800 amp hour battery bank would now only weigh (800/3.225) 248 pounds

Renogy batteries, being the lightest, hold 100 amps and weigh 28 pounds
This is to say 3.571 amps per pound

The same 800 amp hour battery bank would weigh just a smidge less at (800/3.571) 224.0 pounds.

So, you might be wondering now, aside from weighing half as much, why bother with expensive batteries? They take up about the same space, and if the boat isn’t overloaded, why bother? Well the truth is, all batteries hold power, but they don’t all let go of the power the same.

Think of batteries as a jar of jelly. They all hold the same amount of jelly, but they differ in how the jar opens.
Lead Acid and AGM batteries have a small opening at the top of the jar, so you can get your spoon straight in, but you can’t get to the sides of the jar. When you have gotten all the jelly you can reach, you notice that there is still a lot of jelly left on the sides, but you just can’t seem to get to it!
Lithium batteries have a much larger opening at the top, so you can get to the sides of the jar much more easily. This lets you get to more jelly and leave the jar more empty when you are finished.

Lead Acid and AGMs can safely discharge down to 40%, while Lithium batteries can safely discharge down to 10%. This means that in a 100 amp hour battery, an AGM can give up 60 amps while a Lithium can give up 90 amps.

So, back to our hypothetical 800 amp hour battery bank, made up of eight 12 volt batteries. The batteries sitting in their box hold 800 amps hours. If these batteries are AGM or Lead acid, they could only give out about 480 amp hours. This identical battery bank made of Lithium batteries could now give out 720 amp hours. That’s an additional 50%, from half the weight!

So, bringing the battery bank and electric motor out of the hypothetical realm and into reality:

Our electric motor draws from our battery bank composed of eight AGM Group 31 batteries, each with 105 amp hours. We can motor at a slow speed of 2 knots for about 20 hours, giving us a range of 40 miles. With a Lithium bank, we would be able to motor 60 miles! That might not sound like much, but that is a lot of miles from the same size of battery bank. Yes, more batteries would give more miles, but space is an issue on a sailboat.

The switch to Lithium will be coming, and we will then be able to compare lithium batteries to AGM in terms of usability and performance.

What is the Purpose of a Stern Overhang

Long overhangs are a common design characteristic of CCA (Cruising Club of America) boats that were very popular back in the 1950s and 60s. These yachts sported short water lines for their length overall and had significantly long overhangs. Wisdom, as pictured when I bought her in 2012 is 45 feet long with a 32 foot waterline. Simple arrhythmic will tell you that we have 13 feet of overhang, most of which is located in the stern.

The idea behind this design is simple, at rest, the yacht has some lovely overhangs that look timeless and classic, but also help cheat the racing rules at the time. The rules measured the boats waterline for its handicap rating, since waterline length directly correlates to maximum speed through the water. A 45 foot yacht has a hull speed of 8.98 knots while a 32 foot yacht has a hull speed of only 7.58 knots.

So, the large yacht with long overhangs gets rated as a smaller yacht with a lower top speed. Then when the wind comes, it heels over and that long overhang goes into the water, giving the speed boost because of the longer waterline.

The stern overhang is the most effective area for this cheating to take place, as it can quickly fall into the water with very little heeling.

We sailed most of the time heeled over to 10 degrees, and the fouling scum on our topside paint is evidence of what parts of the overhang spent the most time underwater. The blue line demarcates the resting (vertical) waterline while the green line demarcates the heeled waterline. The yellow area between the lines is the added wetted surface.

After spending close to a month sailing from Bermuda to the Azores, the fouling growth is very evident on our topside paint. It is plain to see that the bow overhang doesn’t contribute to the added waterline length while the stern adds a considerable amount of length.

Next time you see a yacht with a long stern overhang, imagine how the waterline changes as they sail and that long stern overhang splashes into the sea!