This achievement has you visit the bowspirits on 5 shipwrecks in the Draumheim ocean (the water up above). The reward is Reginald, a Harvesting/Artifact minion.
If you've forgotten how to get to the ocean above - jump on the little jellyfishes next to most porticulums in the zone.
The swim buff from Ember Isle is recommended (port to Breaker Point in the middle west, dive west and down, use the blue crystal).
Jump out to the bowspirit (pole coming out from the front of the ship). There's some wood sticking up blocking your path - just mash jump while running straight into it and you will go right over it.
There's named level 65 elite mobs around some (and sometimes invasions too(??)). These mobs give 10 void stones each, though any further purpose is as yet unknown.
Exodus Quester - 6121, 4922
Ocean Horror - 4613, 5845, under the water!
Deceitful Mermaid - 6172, 4974 (right next door to the Quester)
Night's Fall - 6160, 7066
Draum's Doom - 5413, 7004