The boat brief outline.
The side door of a dwelling. with a door/entrance open and partial view of the interior. Outside the door is a medium to large boat/water based vehicle on a trailer, the vehicle in under repair, or being loaded for a trip and is surrounded by parts/items/boxes/kit etc. A pet sits in/on the vehicle waiting for its owner to return.
A few ideas for a submarine scene.
My final idea and a photo of a scene.