Have a look at page 1 of Book 1 of classic Traveller. It says there that the game setting was inspired by 18th century history.

Specifically, the fact that communication was limited to the speed of travel. Either Loren, Marc or both have also mentioned the Age of Sail in general, the Roman Empire, and the South Sea Islands trade in the 1930s as specific inspirations for Traveller.
As for the characteristics of the Age of Sail, I'd say these are the main ones, all stemming from that basic fact that communication was limited to the speed of travel.
1. If you get into trouble, you can't just call for help. You have to sort things out yourself.
2. The government is physically incapable of micromanaging affairs from a distance. Instead, they have to appoint trusted people - plenipotentiaries or viceroys - and give them full responsibility for running things. That means that the local governor or noble in charge might well have some odd ideas about the best way to deal with a crisis, which can get player characters involved...
3. Criminals can remain at perfect liberty as long as they move faster than the warrant calling for their arrest. This is also something that PCs can benefit from.
4. Trade is speculative because there's no way to check the price or availability of goods without physically travelling to the source to buy them. Equally, you won't know what the demand will be in your market until you've physically shipped the goods back home - if you arrive back to find a rival merchant has just reached port and glutted the market by selling his own cargo, you'll only get a much lower price for your own goods. That's why clippers were built to be so fast - the first shipload of tea from China arriving back in England each year could get many times the price of the second shipload.
5. Piracy in the Age of Sail took three major forms.
First, there's the classic 'arr, Jim Lad' full-time pirates. These were a lot rarer than Hollywood makes out, and most had very short careers. They often used stolen ships which had their superstructure cut down for extra speed, and so fell apart after a few months (so they had to steal a new ship...).
Second, there's government-authorised privateers. These were extrememly common in wartime... and if a British ship meets a French ship somewhere in the Indian Ocean after a six-month voyage from home, how was either supposed to know whether their two countries were currently at war or at peace? Safer just to open fire anyway, and blame "pirates" if it turned out that actually, they were at peace.
And finally, there's what the TML used to call "ethically challenged merchants." It's simple enough: all merchant ships were armed, to protect them from pirates. If two ships meet at sea, neither can call for help (no radios, remember?) so if the larger and more heavily-armed ship decides to indulge in a little piracy, who's to know? Human nature being what it is, this sort of thing happened all the time. Eventually, large government-organised navies decided to stamp out piracy, but it took a long time and only really happened near the end of this period.
6. At the beginning of the Age of Sail, all ships were privately owned. Even 'royal' ships were owned by the King and paid for with his own money. If a country went to war, the government would hire as many private ships as it could afford, and organise them under an admiral. Even by the 17th century this system was still in effect, although goverments tended to pay for more 'King's Ships' to act as the hard core of the fleet, in case they weren't able to hire enough private ships. It was only by about 1650 onwards that professional navies of the type known today really started to form.
7. Mass migration really wasn't an important feature of the Age of Sail. The colonists who headed out for the New World were relatively tiny groups, a few dozen or a hundred or so at a time. You actual mass migration happenened in the 19th Century as a result of the invention of the steamship.