So I just dove to a skeleton captain voyage and it took me to Discovery Ridge, with the skeleton spawn point being the mermaid painting on the west side of the island. Most of them spawned fine, but the final captain somehow spawned inside the cliff wall. Thankfully I was able to use a keg to kill it and complete the voyage, but couldn't get the skull. It's not the end of the world (though if I -had- gotten it, it would've tipped me over to the next tier on the emissary board) just thought the team should know.