They're rare, and our chosen sport is actually relatively safe, but here's our top 10 things to avoid at sea...
Hitting the pontoon
Even a gentle bump can cause a lot of damage... usually more to your boat than to the pontoon! The biggest problem is when the breeze is gusty and you are in an unfamiliar boat... most problems come from approaching with too much speed (read Marina berthing: 10 tips for perfection).
Losing the rig
All the more reason to check your rigging regularly! It only takes the failure of one component, so make a rig check part of your regular maintenance routine. In fact general boat maintenance can help you avoid a lot of problems, see How to maintain your boat.
While capsizing is all part of smaller dinghy sailing, in a bigger boat capsizing is not a good idea and usually a result of losing a keel... unless you're giant multihull like the AC72 Oracle... see Oracle AC72 Capsize: Amazing Photos.
Even doing all the right things like ensuring you check the weather forecast before a trip, keeping a good lookout and maintaining your boat properly, sometimes you can be unlucky. Boats actually can go down very quickly... faster than you might think (see Dramatic sinking captured on video). That's why ensuring your safety equipment is in place and in working working order is essential because the worse can happen, however careful you are (see 14 tips to make sure your safety gear is in order).
After watching the video you might wonder why did the Extreme 40 crash into the sea wall in Cowes? It was down to rudder failure... if you've got a bit more sea room and are going a bit more slowly you might be able to avoid a collision, but you're likely to need help to get home.
Every year there are collisions at sea, if you're a leisure craft you need to be especially careful in busy shipping lanes and always assume a large ship hasn't seen you - be definite in your movements and keep out of the way.
Many launching problems can be avoided by taking it slowly and launching from places you know are safe and taking a proper note of the nature of the launching ramp.
Some boats simply aren't suitable for a rough sea state... make sure you check the forecast, don't overload with supplies or people and be aware of your craft's limitations.
Hitting the bottom
Less of a disaster if you are sailing in muddy creeks, or racing inshore in lighter conditions... but hit a rock or a sandbank when the weather is up and there's not likely to be much of your boat left, not to mention the danger to the crew. Old wisdom is right; it's generally safer out on the open sea than too close to the coast when you get caught in a storm.
On land or ashore fire is both a friend and a foe. Making sure you have the right fire extinguishers, which are in date and have been properly serviced, located in the right places - by the galley and engine, for example - is key. Fire can take hold very quickly on a boat and result in disaster. Be aware of the dangers of gas on board (see Gas safety onboard: guide for yachts and powerboats) and ensure all your appliances and the engine are regularly serviced.
You can see a montage of disasters on video: Ultimate boat failures: crashes, capsizes and wrecks.