FS2004 ATC Mod Supermarine Sea Otter. Voice pack modifications for the Supermarine Sea Otter. The Supermarine Sea Otter was a British amphibian aircraft designed and built by Supermarine. It had a range longer than that of the Walrus (from which it was derived) and was the last biplane flying boat to be designed by Supermarine. It was also the last biplane to enter service with the Royal Navy and the RAF. To be imported using EditVoicePack (EDITVP31.ZIP). By Mike Stallwood.