One of the principle attractions to the port of Baltimore is the abundant lack of "Massholes".(g)
On a more serious note, the port of Baltimore is much more congested, as compared to Boston, with commercial ship traffic. Most shipping lines do not even call Boston any longer. Largely due to the longshoremen. (where did you think the term "Masshole" came from?)
Well, I count four exams. 3/M, 2/M, C/M, and Master. All Oceans, unlimited tonnage, steam or motor. The only one I ever had to renew is the Master's.
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.