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Rewards: Broken Sword Knife Recipe, $750
To the far east of central Boston, you can find this chest at a congregation of British Soliders. They will be guarding the chest which is against a wall, so go to town on the guards in your way to get access to the chest.
For this chest, you will need to swim over to the east docks and to the ship that is guarded by 4 guards. Climb up the side of the ship and you will be able to pick the lock of the chest undetected.
Reward: $1454, $750
To get access to this chest, you will need to complete a few Liberation Missions in Boston. Once you have completed a few of them, you will then get access to the Liberation Contact in the Central section. Enter the building at the map marker for it, and then take a walk to the second floor to find the chest. Thankfully you won’t need to pick this lock.