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The Speed of Light & The Challenge of Delivering Broadband Internet at Sea

In a world where we're constantly connected, those new to cruising are frequently shocked to find out about the high cost and sometimes poor speed of cruise ship internet connections.  We've written before about staying in touch at sea, as well as various lines' efforts to better connection speeds and prices on-board cruise ships.  What we haven't discussed is why it's so tricky.  We'll try to keep things relatively simple, but be ready to get nerdy as we examine why the speed of light isn't fast enough when it comes to WiFi on the high seas.

The State of Internet on Cruise Ships Today

Think back to hotels 15+ years ago.  Some had high-speed internet, others didn't.  Often you needed to plug your computer into an Ethernet port (wired vs WiFi), adjust settings, etc.  However you got connected it may have only been in option in certain parts of the hotel - not everywhere.  These days you can be pretty sure that most hotels you stay at in developed nations will have fast internet throughout the property - and it'll likely be free.

Depending on what ship you're cruising on you'll find today's shipboard internet access to be somewhat similar to hotels in days past.  Most have WiFi now, and for the most part that WiFi coverage is available throughout the ship.  Once connected to the network however, the speed and reliability vary depending on the ship - sometimes slower than dial-up and other times quite quick - and the price is certainly not free (though occasionally bundled with the cost of the cruise.  Many ships still charge for access by the minute, and you'll use a lot of that time for the simplest of tasks.  The systems in place on many Royal Caribbean ships (and those of her sister line Celebrity) are quite good, and currently the "gold standard for internet at sea), but they're the exception to the rule, and still not quite as quick as what many have come to expect.

How We Stay Connected on Land vs at Sea

Let's start here by clearing something up:  When you're using the internet at home or around town it's probably coming to you via satellite.  This is a common misconception.  Mobile phones don't use satellites (well, for GPS - but that's a different story) and your home broadband isn't traveling via satellite either.  When you load up a website or an app you're connecting to the internet via a giant network of cables which run all over the world, including under the sea.  Now, walking that back a moment, there are some people, usually in remote areas, who may use a satellite dish for their home internet connection.  Those systems (in addition to being slower than cable and other methods) use a phone line or other technology to communicate in one direction, and only download via satellite.  Further, the satellites are positioned over populated areas, so the distance the signal travels is much shorter, and the target is a dish at home, not a moving ship.

map of undersea cables - submarine cables
map of undersea cables (click to enlarge)

Undersea cables have been keeping us connected since the first submarine telegraph cable in 1858.  Every phone call across an ocean, and every website you load up from a far-away land.  As you can see, this actually works out pretty well.  These cables require a lot of work and maintenance, but allow us to move information at incredible rates.  Once the information gets close to you, it's usually distributed to you via telephone lines, cable TV coax, or cellular signal.

Obviously, having an incredibly long extension cord that cruise ships all drag around isn't practical; ever try to untangle 9,000 miles of Christmas lights?  To solve for this, ships use two different ways to stay connected: land-based radio systems and satellites.  Some ships have systems which, when within 50-100 miles of land, use land-based radio systems very similar to cellular data networks (but with larger antennas and fancier equipment).  These can actually work quite well when in range.  When out of that range however, satellite becomes the only option.  This means that everything you do with an internet connection needs to make all the normal trips around the globe plus travel up to space and back again.

The Challenge of Satellite Connectivity - Gettin' Nerdy

Satellites carry a feeling of being so high-tech that they're the answer to our challenges, yet in this case they present a significant challenge.  One challenge is of course cost - the price of getting technology into space and keeping it operational is high - but beyond that, the problem is distance.  Let's start by looking at how we measure speeds on the internet: bandwidth and latency.

Picture a conveyor belt moving items across it. 

The width of that conveyor belt is the bandwidth.  The wider the belt the more you can move at once.  With a little bit of bandwidth you can move a text file, or maybe a phone call.  With more bandwidth you can move HD video and more.

Now how how long it takes those things to get from one end of the conveyor belt to the other depends on how long the belt is and how fast it's traveling, right?  That length of time is latency.  

When you use the internet on land, the data could be coming to you from a few miles or across the world.  If you're on a large site and in Europe or North America, there is a good chance that this information isn't traveling very far as it's replicated somewhere near by so it can be quickly delivered to you.  In cases where the information you're accessing does need to travel far, it's traveling via fiber-optic cables which allow very fast transmission of information.  

While using a satellite internet connection (on a ship for example), every single request must travel up to the satellites, back down to earth, and then to the servers - which could be located nearby, or thousands of miles away.  This process results in very high latency.  If you use a speed test app on your phone right now (and you're not on a ship), you'll probably have a "ping" time (this is how we measure latency) of somewhere between 5 to 30 milliseconds.  This is because you're testing against a server nearby (within a thousand miles in most cases).  If you did this same test on a ship however, that data would have a much longer distance to travel. 

Many satellite systems used by ships are operated by a company called O3B/SES, which has a mission to provide broadband internet to everyone.  In fact, O3B is actually called that because of the "Other 3 Billion" people in the world who don't have access to high-speed data.  These satellites are mostly at around 5,000 miles above the earth.  This means that even if a satellite is right above the ship (which it usually isn't), the message must travel 5,000 miles to the satellite, over 5,000 miles back to an earth-based receiver (traveling at an angle - the earth-based received isn't directly below the satellite), then to the servers with the data you're looking for - which could be thousands of miles away.  This must happen all over again when the data comes back to you on the ship.  That's easily 12,000 miles in total without calculating the land-based trek.  This satellite data is moving via RF, which travels at the speed of light: 299,792,458 meters per second, so that results in over 64 milliseconds of latency.  Add in a 2,000 mile round-trip through fiber-optic cable on earth and that's another 16 milliseconds.  You then must factor in the network hardware, etc and you can see that 80-120 milliseconds is expected even with the best of satellite connections.

There are of course many other challenges - such as dealing with a focused satellite signal on a ship that is moving in all directions, nevermind weather conditions which not only exacerbate movement but also obstruct the signal with water vapor.  High-gain receivers, noise-cancelling technology, and stabilization systems for the receivers/dishes themselves all help to overcome these challenges, which were true barriers to satellite connectivity not long ago.  We focused above on latency however because it's something we have less control over - we can't control physics, but we're sure to work on new technologies which help us achieve faster connections.

I Can Stream Video on Voom - What Does This Matter?

As more ships use technology similar to Voom, the good news is that for now, for most users, this doesn't matter.  High latency can negatively impact hardcore PC gamers, but that's about it.  Things get challenging as we demand more from technology.  Higher resolution, 3D, augmented reality experiences push the limits of our technology even on the ground, and servers used by businesses (including cruise lines) may have technological demands that simply can't be met with the current restrictions.

How Can The Technology Improve to Keep Up?

For lines that still offer "dial up" experiences, they can (and surely will) begin using technologies we currently have and are capable of scaling.  We can't of course increase the speed of light, so that's somewhat restrictive.  Can we transmit data wirelessly within our atmosphere over longer distances?  Well, there are ways, and we've been doing this for years, but for a number of reasons this is not likely the solution (for one, to do this the signals bounce around our atmosphere multiple times).  One option is to leverage satellites in lower orbits to reduce the overall travel time.  In fact, many ships have started leverage Starlink for internet service, and those satellites are indeed in much lower orbit, resulting in lower inherent latency (though it still depends on how cruise lines implement these systems).  Another thing that will continue to happen is that the data centers where information is replicated to reduce latency on the ground will grow and hold more information in more places so that at least when the ground-based stations get the message from the satellites the data will have less distance to travel to get to it's final destination.  What else? Well we're not sure - this is a cruise site, we're not rocket-scientists!

Wrapping it Up

Consumers demand the ability to stay connected wherever they are, and many lines can do better when it comes to their internet connections, but the technology still struggles to deliver.  We know that while technology will keep improving, our demands upon that technology will continue to grow as well.  What the cruise industry has to gain is customer satisfaction of course, but also amazing marketing as people share their vacations from wherever they are.  Further, consumers increasingly work from outside the office, both while on vacation and day-to-day, and any destination which requires being disconnected will increasingly be off-limits.  

Sure, there is something to be said for wanting to disconnect while cruising.  Every time I sail I get excited about sharing my experiences with the world but at the same time I'm conflicted because I miss the days when we sailed away and knew that nothing that happened at home could matter during the trip, because there was no way to know about it or anything to do about it until our return.  At the same time, we recently talked about how while we long for the good old days of cruising things are pretty great now.

What is remarkable, more than the technologies themselves, are how quickly we've become reliant on connectivity.  Hopefully, knowing a bit more about how this works will make it a little less frustrating when it takes an extra second or two to upload that picture of your dessert on your next cruise.  Your friends are already jealous, there's no rush.

Have questions about the technology that lets us Tweet from Tahiti or Skype at sea?  Comment below or reach out on Twitter or Facebook.