I was lucky to join Bob Marx for full five days during his visit on UNESCO Underwater Heritage Conference held in Santo Domingo three years ago and I experienced several of his official lectures he had given here in the city as well. His memory is unbelievable at his age, he remembered perfectly dates, names of ship masters, names of capes and rocks, detailes, just everything. In spite of his "specific language" (almost everybody is fu..... *******, you know a sh....., and so on), his knowledge and personal experience have no comparison in treasure hunting and underwater archaeology.
It is highly recommended to attend any of his lectures.
Best regards,
Lobo