Consulting Grose (for what it's worth) there is the following definition in 1811.
TO WAP. To copulate, to beat. If she wont wap for a
winne, let her trine for a make; if she won't lie with a
man for a penny, let her hang for a halfpenny. Mort
wap-apace; a woman of experience, or very expert at the
sport.
WAPPER-EYED. Sore-eyed.

Considering the Ratcliffe area and it's reputation the word may well have been in common usage. That said Grose would be working for the Sun Newspaper in this day and age. So take a pinch of salt, or any other available dockyard spice!