It's taken a little while, but this remarkable story is now available in the USA via the following:
Barnes and Noble (http://www.barnesandnoble.com/w/chasing-black-gold-robert-stone/1121230480?ean=9780750960335)
Books a Million (http://www.booksamillion.com/p/Chasing-Black-Gold/Robert-Stone/9780750960335?id=6779183069437)
...and in Canada from Chapters Indigo (https://www.chapters.indigo.ca/en-ca/books/chasing-black-gold-the-incredible/9780750960335-item.html?ikwid=Chasing+Black+Gold+by+Robert+Stone&ikwsec=Home&ikwidx=0)
I had the pleasure of working with Robert over several years, firstly to nail down this story, then to write it, and finally to get it to publication. We are already looking at a follow-up, which will go deeper into his smuggling, treasure-hunting and deep-sea fishing activities.