The only way to get this achievement is through money and apart from the in-game chests & quest rewards, which I spent on equipment upgrades, this is the easiest method I found to get the money need.
edit: Please note, you can also sort the Trade Ships out from any owned shop, as well as The Hideout.
!!! What each city Provides & Demands changes per sequence !!!With frigates, this route takes ten minutes, and nets between ê14,000 - ê16,000 per ship. The only peril on this route is a Storm, which sets the afflicted frigate back by a couple of minutes or so.
S: Speed -
CS: Cargo Space
Galleon: S: 52 -
CS: 130 - ê3,700
Schooner: S: 138 -
CS: 50 - ê4,000
Barque: S: 58 -
CS: 150 - ê8,000
Brigantine: S: 150 -
CS: 60 - ê9,000
East Indiaman: S: 60 -
CS: 200 - ê13,670
Brig: S: 175 -
CS: 70 - ê15,800
Frigate: S: 120 -
CS: 130 - ê19,650
You start with one Galleon, for free, so you only need to buy 7 more ships. That means you only need ê25,900 to buy 7 more Galleons.
The main three to choose from in Speed/Cargo ratio are the Galleon, East Indiaman & Frigate.
Using the route I described above I timed a single ship, of each of the three types and tallied the total money and time at the end of step 3:
Galleon: ê31,200 - 46:08
East Indiaman: ê48,000 - 39:58
Frigate: ê31,200 - 19:58
As I found out, the frigates are the better choice for the naval trade missions, whilst the E.I. can bring ê17,000 more, the frigate can do the same route twice in just under the same time. The Galleon has the same cargo space as the Frigate, but doubles the time needed compared to the frigates.
This is also very handy for getting the funds needed to purchase the pocket watches from the smugglers, prices for which can be found here:
My personal favourite route is for later in the game, or in post game achievement clean up and is as follows:
1: Firearms - from Bordeaux - to New York
2: Furs - From Boston - to Bordeaux
3: Send the ships that arrive at New York to Boston
4: Repeat until the needed money total is acquired
If anyone wants to post any personal route they prefer and/or the ships they use on the route, as well as the Sequence you're currently on, please post in the comments, I'll add them to the guide with credit.
Sequence 7 - from
Akinokaze FA1: Iron - from Seville - to Port-Au-Prince
2: Spices - from Port-Au-Prince - to Seville
Hazards: Storm 30% & Hurricane 10%