This might contain SPOILERS for "Lair of the Leviathan".
When I interrogated Noogie about the Tongue of the Manatee on the ship, I just chose the option "ARRR" and made a face - and it turned out to be the solution! I was confused about Noogie's "Sister Agnes" comment, but I was glad it made him talk.
Afterwards, I looked through de Cava's crew member files... and there I saw Sister Agnes!
Anyone else who made that face by chance, without knowing of Sister Agnes before?