They're in Forgotten Fane of the Coiled Goddess. And one of the TSR Conan AD&D adventures (with Arnold on the cover) from the 1980s features them.
"Could you fancy me as a pirate bold? Or a longship Viking warrior with the old gods on his side? Well, I'm an inshore man and I'm nobody's hero. But I'll make you tight for a windy night and a dark ride."--Jethro Tull