I grew up in Puerto Rico going to La Parguera every weekend, then I moved to the states and missed those beautiful waters every day I was away.
Sailing back into the waters of La Parguera was incredibly special! I was finally able to show Maddie, my wife, all the places I swam and explored as a kid. We even went to the bioluminescent bay, also called the bio bay, where Maddie went skinny dipping!
Hiding in the lee of an island is a great way to protect yourself from punishing winds. The land blocks the sea from building waves that will rock your yacht as well as blocks the wind m, allowing you to anchor rather peacefully in some horrible conditions!
When you are looking at a new place to go cruising and need to find happy hiding holes that you can tuck into if the wind builds, how can you figure out how far away from land you will still be protected?
Navionics will tell you the elevation of various points on a landmass. Some are in feet, some are in meters, but the math all works out the same.
The equation is simple:
Elevation in Nautical Miles x 20 = Distance of wind shadow in nautical miles
For example: 564 feet (elevation) / 6076 feet (number of feet in 1 nautical mile) = 0.09nm tall
0.09nm x 20 = 1.85nm wind shadow
In other words, if you are within 1.8nm of that point of land, you will experience much less wind as you will be shielded from it.
Another example would be 168m right next to it:
168m x 39 (number of inches in a meter) = 6552 inches / 12 (number of inches in a foot) = 546 feet / 6076 (number of feet in a nautical mile) = 0.089 x 20 = 1.79nm wind shadow
To make it easy, just do these calculations:
If the elevation is in feet:
Elevation / 6076 x 20 = Windshadow
If the elevation is in meters:
Elevation x 39 / 12 / 6076 x 20 = Windshadow
Do you need to have radar on your cruising boat? The short answer is: “No” but the long answer is: “Maybe”.
It really depends on where you plan to cruise. Are you aiming your bow for warm tropical waters? In that case you won’t need radar. If you are going to more “unique” destinations where fog is a normal part of life, then suddenly radar becomes a very valuable tool.
Radar has many uses on a boat, many of which I do not find to justify the cost of the unit.
The most proclaimed reason is to “watch the weather so storms don’t sneak up on you”. The reason is radar will pick up dense clouds in your surroundings and that will alert you to the presence of a storm. Do you know what else detects the presence of dense clouds in your surroundings? Your eyes! You already have them and you don’t have to shell out any boat bucks to buy them.
The classic rebuttal to this statement is: “but what about at night when you can’t see the clouds because it’s dark?” I have found this to be a false argument because at night, the clear blue sky is replaced by a black sky filled with stars. If there is a moon, suddenly it becomes less dark, but still filled with stars! When clouds roll in, patches of the sky lose their stars and become just black patches.
As you spend time out there, you will become very familiar with the different constellations and will quickly notice when you can’t see Orion or Scorpio or Gemini or Pegasus. When you can’t see parts of the sky and the stars are quickly disappearing, you also know that clouds are rolling in and a squall is going to hit soon. Once again, you don’t need radar to alert you to weather changes.
The idea is if you are entering a harbor in the dark or if you are sailing near land in the dark, the coastline will be drawn on the radar screen. This is useful for identifying rocks that are above water and cliff faces.
I have two major problems with this idea. First, you should never sail into a harbor or near land in the dark. There are so many things that could happen that you just won’t see. Minor things like fishing traps that will foul your propeller to more dangerous things like a submerged log just beneath the surface. If your travels have you arriving after nightfall, either heave to offshore and wait for daybreak or drop anchor outside and enter the harbor at dawn.
My second major issue with this is electronic charts do this exact function and are a fraction of the price! I have Navionics on my phone and it draws all the coasts in perfect detail. It goes one further and also shows me the bathymetry of the sea floor which is something radar still can’t do. Why pay thousands of dollars to have a thing draw the coast when you could have the same thing on your phone for about $20 a year?
If it’s dark out and you can’t see, Navionics will show you the way, if you get hit by offshore fog, Navionics again will show you where land is so you can avoid hitting it.
Land and rocks don’t move. They are also well charted, which means that the electronic chart will help you avoid hitting a shore that you can’t see.
This one has some validity to it. The idea is that if a boat doesn’t have lights on (because they are an idiot) and their speeding around you in the dark, you will be able to detect them on your radar. This also applies to non-idiot boaters who do have their lights on and are simply approaching you. You can set certain parameters so that if someone comes within a certain range of you, an alarm goes off to notify you of their approach.
The reason this is somewhat of a valid point is because AIS does this exact same thing. You can set your AIS to do these same functions but it only works if the other boat is transmitting AIS.
As of right now, all commercial boats have to transmit AIS (Class A signal) while recreational boats don’t have to; and if they do they transmit Class B signal. If you are crossing an ocean, you will have over night passages and you will be sailing downwind (or you are going the wrong way and want to reconsider your route). All other private vessels that are sailing across the ocean will be going in the same direction, so an approaching vessel has to be going faster than you to come from behind or you have to be going faster to approach someone else’s stern. In other words, a head on collision with another sailboat is very unlikely!
The only boats that will not be going downwind will be power boats. These will consist of massive commercial cargo ships that will be transmitting Class A AIS and massive private motorboats which will most likely be transmitting Class B AIS. The reason it’s safe to assume that only massive and expensive power boats will be out there is these boats have to carry enough fuel to cross an ocean! Unlike sailboats which rely on the wind to power them across the great blue sea, power boats need diesel to move, and lots of it! The fuel cost for an ocean crossing will eliminate all possibility of a person with limited financial means being out there on a motorboat. If they can afford the fuel, then they can also afford the electronics that make those boats fancy, and one of the first electronics they will install will be AIS.
Think about how many times you see a derelict sailboat cruising around and enjoying life as the captain gets to freely sail to new destinations and explore the world. Now think about how many derelict power boats you see doing the same thing? Wind is free and food can be found. Sailors can live a happy life on barely no money where a power boat needs to have money to purchase fuel. No fuel, no moving, no exploring, and no living an awesome life! In other words, a powerboat in the middle of the ocean going against the wind belongs to someone who can afford AIS and therefore would show up on your AIS display. A sailboat in the middle of the ocean may belong to a happy boat person who is traveling the world on a tiny budget (much like we have been doing for the past 5 years) and doesn’t have AIS but will be going the same direction that you are!
To summarize, AIS is wonderful but only works if the other boat also transmits AIS. Out in the middle of the ocean, everyone is going to be moving the same direction so if someone isn’t transmitting AIS, they will not approach too quickly. Where this becomes a big problem is sailing through island chains where boats will be traveling in all directions and may not be transmitting AIS! Here is where radar becomes very helpful as an adjunct to AIS. If anything approaches, transmitting or not, it will be detected by one of the two systems and you will be notified of their approach!
This is the real reason to have radar! Storms can be seen with your eyes, day or night, other boats can be seen by keeping a proper watch and using AIS, but fog is blinding! Thankfully, when fog rolls in, the winds are also light or nonexistent, so if you are sailing you will stop moving. This means that if you are purely sailing out in the ocean to destinations that are not routinely covered in fog, and fog appears; you will come to a stop and if you do bump into anything it will be slowly and hopefully less damaging.
What if you are sailing the foggy coast of Maine or near England? The wind can die as the fog rolls in but that doesn’t mean the tidal currents will slow. Suddenly, you might find yourself with no wind in your sails, no visibility, and being swept away with the tide.
Rocks and shorelines are still visible on your phone with Navionics, but what about all the anchored boats or small craft that might also be caught in the same situation? You are blind and suddenly surrounded by a lot to hit while moving quickly!
This is where radar shines. To answer the earlier question of “Do you need radar to go cruising?” The answer is “No” because you can go cruising in places that are not plagued with fog. Head to the tropics where the water and air are both warm and fog is a rare sight to see.
We have been sailing around successfully for 5 years without a radar unit and we have done our best to avoid sailing in fog. We have had a few instances in the middle of the ocean where we came upon fog (it looks like a big grey wall in the moonlight) but it burns away as soon as the sun comes out.
One instance that radar would have been very helpful in was when we were sailing out of the Bay of Cadiz in Spain. We were anchored and a dense fog rolled in while we were preparing to sail to Morocco. We continued to prepare the boat as we waited for the fog to lift, and once it did, the world was clear and visible once more. We raised anchor and as we were sailing out of the channel, the fog came back onto us! With Navionics, I was able to overlay the AIS display on the chart on my phone’s screen; this made me feel safe sailing blind as we made our way out into the open ocean.
AIS shows me where all the boats that are transmitting AIS are located and the electronic charts show me where land, rocks, and all the buoys are located. So far, so good! But what about someone else sailing in that area who is not transmitting AIS? They would only show up on radar and I was not privy to that information.
Instead of sailing around in constant fear of crashing into an unknown vessel in the fog, I radioed the nearest commercial cargo ship (whose name I was able to get off the AIS screen) and asked if they had anything showing up on their radar that wasn’t showing up on their AIS display. The captain confirmed that everyone on his radar screen was also transmitting AIS. This meant that I could safely follow the chart on Navionics as we sailed out of the fog and into the ocean. Would I have liked to have radar in that moment? Yes. Did I need to have my own radar to sail out of that harbor? No.
Sailing in warm waters where fog is seldom seen is a nice way to avoid the need for your own personal radar, but what if you are longing to sail in high latitudes where the water temperatures are cold and any moisture in the warm air coming off the land will instantly condense into a thick cloud of fog. What are your options when it comes to radars?
The cheapest option is to have someone stand on the bow throwing potatoes as far as they can. As long as the person on the bow hears a splash, it is safe to proceed moving forward. If the person on the bow hears a thud, STOP!
The Halo24 is a powerful radar unit that can see things up to 48 nautical miles away! As you can imagine from it’s name, it is 24 inches in diameter which makes it “compact” as far as radars go, yet big enough to give you a lot of usable information.
“Real” radars have a really REALLY wide antenna which spins around. These are called Open Array antennas and while they give you incredible detail at really long distances, they have one massive problem on a sailboat: Rigging. Open array radar antennas will get fouled in your rigging, be it a halyard, or a part of the sail. At some point, it’s going to get tangled and that will make a mess. Radar manufacturers know this and in an effort to find more ways to sell more stuff to sailors, they figured out how to put all the moving parts inside a small dome shaped container, cleverly called a Radome (or Radar Dome).
While this unit is compact and will give you lots of information about your surroundings it does come at a cost. This radar unit will cost you about $3,600 and also consume about 17 to 25 amps per night (over a 10 hour night). Your wallet will take a little bit of time to recover as you wait for the sun to come out and charge up your batteries through your solar panels.
Going a little smaller, this radar unit is only 20 inches in diameter. While less might seem better on a sailboat, the range is also restricted (as the antenna is smaller to fit inside the smaller container). The range on this unit drops along with the price tag. This 20 inch radar can see a whopping 36 nautical miles and will cost you about $2,300!
While it is smaller, the power consumption is still around the same as the Halo24.
An important thing to note when it comes to various brands, they all have about the same power consumption, range, and size because these limitations are controlled by the laws of physics. Radar needs power to work, and the range is dependent on the size of the radar. Making the radar bigger does increase its range but this also increases its usable area. If you can see something farther away, you will have more time to react to it and this will make close encounters at sea a rare occurrence as you can steer clear of obstacles long before they come into visual range.
Not that you could actually put one of these on your sailboat, but this is the ideal radar antenna. It is very big, very wide, and very powerful. This unit uses a ton of power and costs a fortune but will provide you unparalleled detail of everything around you. The largest and most powerful antennas can spot and distinguish between birds in a flock over 70 nautical miles away!
Why? Well, flocks of birds are useful to identify where fish are because a flock of birds will collect over a school of fish, so if you are trying to find fish in the big empty sea, then finding birds in the sky is going to be a good starting point. While power boaters are interested in identifying what and how many items there are in the distance, sail boaters don’t really care about such detail. A fisherman wants to know where the birds are in the distant sky and how many there are, as well as how they are moving. A sailor wants to know where something in the water is so that they can steer clear of the obstruction and avoid a collision. It doesn’t matter how many items there are in the distance because a sailor will avoid the entire area!
If you had your heart set on having the best most precise radar antenna on the market, and wanted to mount it on your sailboat, you would have to fit a very narrow set of rules to make it work. First you would need a ketch rig that way you would have a mizzen mast. Second, you would need internal halyards so that no halyards are flapping around and getting fouled on the long antenna. Third, you would need in mast furling so that when the sail is stowed, there would still be no halyard around. Fourth, you would need a rigid vang so that you wouldn’t have a topping lift on the main boom.
In other words, you would need to have a powerboat with two masts on it to have this kind of radar antenna. That is why the smaller Radar Domes or Radomes exist and are so popular on sailboats. The entire assembly is crammed into the small plastic case, protected from impact and fouling of lines high above the deck of the boat.
In conclusion, radar is not a mandatory piece of equipment standing in your way of cruising freedom. It is a tool that is useful in a fog. All other applications for this tool are superfluous as they can easily and more cheaply be accomplished by other pieces of equipment on your boat. If you have a small budget and don’t think you can afford radar, simply go cruising in the warmer waters of the tropics. If you feel the need to punish yourself repeatedly by sailing into the frigid high latitudes where wicked tidal ranges predominate and fog is a regular part of the landscape (it helps hide the sharp rocks so that it looks prettier), then radar will be a very important piece of gear to add to your cruising yacht.
When looking at the different units, consider where you will mount it, how much it will drain your wallet, and how you will power the device. There is no point in buying a unit that will tether you to shore as you make monthly payments on it and continue to work a land based job instead of cruising, or buying a power hungry monster that will drain your batteries so fast that you can’t afford to run it. Choose a unit that will augment your freedom and grant you access to a broader world instead of one that will cripple your dreams of sailing the world.
And now for the last bit of days from our passage across the Atlantic Ocean.
It was a lot of days, and apparently the website could only support 12 embedded video links per page, so here are the Days 13 onward!
