Booking Manager always allowed you to add documents to the boats themselves, regardless whether they were images, pdf's, Word files etc. Those files were available to any portal or web service user as well.
With the latest 9.4 version of the Booking Manager it is possible to select whether you want make your documents public or not.
Open Work > Yachts, select a boat (1.) and click on Documents (2.) to see all the added documents on the boat.
If you want to enable documents to be public, simply place a check in the Public column for any document you wish to make available to the users on the Portal or Web service.