What are some not-so-obvious skills one should have/learn in order to successfully sail around the world?

I've not circumnavigated but I've done four passages of 3,000 nautical miles between landfalls. I won't address all the practical skills already mentioned but the one thing no one has written about - the solitude.   If you're on a small boat, even with a crew, you're going to spend a lot of time alone on deck with nothing to distract you from yourself. Your horizon will likely be limited to a diameter of 7 miles and all of it the same. The batteries for your music player will soon be drained. You'll be faced by what Joseph Conrad referred to as the mirror of the sea. In the solitude that mirror reflects all your thoughts that were drowned by the noise of civilization, all the bits of yourself you'd rather not acknowledge. I've seen different people affected in dramatically different ways but everyone is affected. As Nietzsche said, when you look long into an abyss, the abyss also looks into you.   My suggestion would be to spend some time alone with nothing to distract you - people, music, books. Make sure you're comfortable with yourself.

I did a circumnavigation about 10 years ago with Clipper. There's a significant difference in the dynamic between a big crew and a small group and you didn't say how you big a crew you were sailing with, or if you were going solo. Anyway, ocean cruising is a marathon. For significant periods of time, you'll be some way from land and there won't be a lot of support for you. Make sure you ( or at least one of your crew ) knows how to fix every single item on your vessel. If it breaks, it's down to you to fix it. You'll spend more time maintaining and fixing than sailing. Even when at sea. The actual sailing, on the whole, is a lot less intense than inshore. There's less to run into ( other boats, rocks, swimmers ), and you can plan your tacks hours in advance. Of course, when it does get bad -- it can get proper bad. Do read the stories of others that have sailed before you go. You'll get all sorts of ideas of things you might need to practice. DO NOT read their stories when you are actually sailing unless you like nightmares. Remember that some of the challenges you will face will be different from anything they wrote about. Don't sweat the customs details too much at this stage -- you can look up all of that nearer the time, although check the Visa situation for countries before you leave. It will probably be simpler to organise some visas before you depart, rather than trying to arrange them on arrival.

In long distance offshore sailing, your greatest asset is your ability to remain calm, understand your limits, problem solve, and most importantly of all, understand your own learning style. There are many systems to learn on a boat. Boats are extraordinary in the sense of how simple, yet how complex they are at the same time. In such a small compact area, you have many systems which have an odd tendency for cascading failure - one thing breaks, and all of a sudden things begin going down hill very fast. At a less abstract level, if you have six years up your sleeve, compartmentalise (list) what is possible to learn on land, ignoring the other million things you'll need to learn once on the actual boat. Read everything, and perhaps steer away from the more technical literature until you're sitting in the cockpit and can make direct correlations between what you're reading and what you're seeing. A big part of sailing is maintaining energy and drive - sailing is very rarely sitting in tropical paradise like you see in the pictures - you'll spend a lot of time fixing stupid stuff which keeps breaking and annoying the hell out of you - you'll spend time in marinas and anchorages feeling lonely - you'll spend time at sea being afraid and wondering why you left the comfort of your own home - etc. On the flip side, you'll also have great insights and experiences which I cannot convey and will be yours, and yours alone. You have six years to dream, and many more years to do, once you're finally aboard. So perhaps what I'm saying is instead of trying to read about diesel injectors when you've never smashed your hand on the water pump while changing an impeller, spend your time on reading famous and not so famous accounts of other sailors so you can dream and also get a better sense of the realities. Many of the minutiae (fishing, laws, comms) are not really study topics - they're things one better inhales through experience. Sometimes a spoon works better for a lure than a cedar plug; don't leave a country without a zarpe (paperless); and if you can, get an SSB: These granular facts are more fun learnt while chatting with some strange old guy in the boatyard, or at anchor with new friends over tinned stew. Read some Moitessier or Sterling Hayden every night and never give up.

In addition to the practical skills listed in these excellent replies, there are also the "softer skills" or personal qualities: patience - circumstances can be difficult for days and weeks, optimism - it was Shackleton who said "optimism is true moral courage", responsibility - you are responsible for yourself, not the manufacturer, not the government, humour, - when all else fails perseverence - stick-at-it-ness, no matter what courage - being afraid and still moving forward compassion - for oneself, for the world. strength of character is at least as important as physical strength, I believe.

Getting from the Eastern Mediterranean to India is particularly challenging given all the piracy there originating out of Somalia. Every other section is challenging in its own right, but the added layer of avoiding/repelling piracy would add an entirely new dimension. Running aground is another risk that should be dealt with. The grounding of Team Vestas in the 2014-15 Volvo Ocean Race (http://www.sailingscuttlebutt.com/2014/12/05/wouter-verbraak-team-vestas-wind-went-aground-volvo-ocean-race/) shows how even the best can make this mistake. Bring paper charts that you can consult in addition to online routing software (on two laptops for redundancy). Routing software doesn't show small islands and reefs when zoomed out. The Volvo Ocean Race blog (http://www.bandgblog.com/volvooceanrace/category/blog/) has great accounts of the challenges faced by round-the-world sailors and is worth a read, even if you're just cruising.

The first five years around the Pacific we had no refrigeration and used a sextant until we bought a sat-nav as we were coming home through the Aleutians where there is little sun for fixes. When the sat-nav went on the blink I took it apart, cleaned the contacts and it started working. I guess that is what you have to learn- if you don't fix it, nobody will- so don't be afraid of trying. Nowadays people have so many systems; refrigeration, sat phones, water-makers, that are difficult to fix unless you have specialized equipment. Don Casey has a great book about fixing old boats. He makes the point that you can pay a shipyard worker to fix something, but who has more to lose when it breaks again? So the more skills- basic fibreglassing, sail repair, diesel maintenance, the better off you will be. Plus having a good sense of humour, because Nature always bats last.

I think a long sailing trip requires less boat handling skills and more emergency and equipment repairing skills.  Below is an excellent story about a person who tried to sail from Los Angeles to Hawaii with a 3 person crew.  It looks like he just put his boat on a broad reach and turned a windvane on to keep the heading.  But he began to have normal equipment failures and then one of his crew became very sick.  This story gives you an idea on how to cope with things that (inevitably) go wrong on a long sailing voyage. http://www.equipped.org/0698rescue.htm Some things that could be helpful to know on a long voyage - AMVER - the merchant vessel emergency program First aid Radio and Satellite phone operations GPS Weather

While I haven't sailed around the world myself, since I was asked to answer I'll take a crack at it. 1. Is this something you really want to do? It is a wonderful goal, but it is hard and dangerous. You will start to figure it out if you do progressively longer trips in challenging environments. Try joining a crew for offshore races, such as the VanIsle 360 or Vic-Maui. 2. Are you going to go by yourself, with a partner, or with a team? If by yourself, can you spend that much time alone without going a bit crazy?  A friend of mine tried a solo circumnavigation and ended up turning back because she just got lonely. If you are going with other people, are they up for the challenge, and can you get along with them for the year or more it will take you. 3. Spend time sailing with people who have done it. Sailing around the world is a whole different type of sailing that cruising or off shore racing. You will start to pick that up as you spend time with people who have experienced it.

1. Know how to handle a sailboat safely in all weather conditions.   a. Take some sailing courses.   b. Get on a few race crew in you local area (start by talking to some yacht clubs that sponsor races to ask who may need crew).   c. Sail, Sail, Sail: In a combination of weather conditions.   d. Charter a small boat and do an overnighter. 2. Be social in the sailing world. Most sailors are a very supportive bunch that are supportive of adventurous newbies who are willing to give and take (like joining as free crew on some boat deliveries or always sticking around to clean up the boat after a day on the water). 3. Be a MacGyver/Mr. Fix it.   a. Owning your own small boat for a few years and learn from books and the people that come to fix her (always stuff to be fixed). 4. Understand that mother nature rules and pays no mind to your schedule or situation. Know that Mother! Do the above for a few years and a good bit of the needed information will fill in.