Unlock the containers where Captain Shandy stashed her treasures in and loot some bleached crossbones. The crossbones bind-on-take, decay after about 2,500 Alyrian minutes, and they must be used in the same room Captain Shandy is in.
Key locations (all in Maldra Keep)
You can carry any combination of the above three but no more than three total (e.g. if you have two hacksaws and a bumpkey you can't pick any more up)
At Captain Shandy's room (A Cramped, Submerged Hideout (30513)), the chest, safe, and lockbox will each have x chains, y gears and z locks. The hacksaw will reduce chains by 1, the battery-powered anglegrinder will reduce gears by 1 and finally the bumpkey will reduce locks by 1. Reduce all these to 0 and they will open. You must wear the appropriate tool and use <tool> <container> to start channeling it at the container. Captain Shandy does not need to be defeated to open these safes.
Each container has a chance to contain the bleached crossbones. Killing Captain Shandy will reset the containers.
For your seamanship and protecting Alyria from the dread pirates, the Powers granted thee a Mark. You have gained the Mark of Seamanship! You gain 48 practices! You gain 400 archon points!