The emissary system accumulates tank based off you doing things pertaining to that faction. Let’s use Gold Hoarder as an example: if you fly an emissary flag for them every chest you dig, every gold hoarder item you touch, put on your boat, every riddle you solve will increase your ranking.

Simply by flying the flag you are put onto the leader board for that month for all sales made while your flag is up. If, however your ranking increases you get accumulated rewards.

At rank 5 with your flag maxed out you will be able to redeem a special voyage from the gold hoarders as well as any loot sold will sell for 2.5x base value and 1.8x reputation with the faction.

This incentivises you to keep your loot as you accumulate it and sell it all at grade 5 for maximum profit.

However, if you sink you lose your flag. You cannot remount it. Other players will hunt for you because of it as well. You can see players flying emissary flags on the little tables at the outpost: each wooden boat represents an emissary on that server.

At the end of your session you can, however, vote to lower the flag and you will be rewarded with some gold and reputation relative to what rank you attained while sailing with it.

Hope that helps.