About 1814 the Russian-American Company renamed an old ship, called "Il'men" or "Il'mena" in works written in English. Ильмень is of course a famous lake.
Boris Dralyuk suggested to Susan Morris that obvious confusion between the spellings could be down to distinction between the nominative and genitive cases. I do have one reference to it in the Russian language, but this spelling appears to be yet a third case:
ПРОБЛЕМ А УЧАСТИЯ АНТИПАТРА БАРАНОВА В ЭКСПЕДИЦИИ НА «ИЛЬМЕНЕ» У КАЛИФОРНИЙСКИХ БЕРЕГОВ В 1814-1815 ГГ.
What is the correct name of the ship? Is the nominative case the one that should be used to refer to it in English?