A Photo has properties of description, place seen, date seen (date) and image (image). A Photo must be seened by one Ship.
A Ship has properties of
name, year built, gross weight, description, kind and category.
grossWeight
A Change has properties of year and name. A Change must be historyed by one Ship.
A Builder has properties of name, website (uri) and abbreviation. A Builder must builder one Ship.
An Operator has properties of name, possibly website (uri) and abbreviation. An Operator may operator many Ships.