Dracula says that Admiral Nelson's body was placed in a barrel of rum. Actually, it was a barrel of brandy.
The rigging and design of the Demeter is far too old for the time period.
Dracula tells Piotr the story of admiral Nelson, and how he was brought back to Britain after being killed in battle by putting him in a barrel of rum. Actually, Nelson was put inside a barrel of brandy. Given the fact Dracula absorbs the knowledge of his victims by feeding on them (and previously had killed a very cultured Englishman), he should know that.