Shares of dry bulk oceangoing shippers Star Bulk Carriers (NASDAQ: SBLK), Scorpio Bulkers (NYSE: SALT), and Diana Shipping (NYSE: DSX) all enjoyed big gains in March, with Star Bulk rising 19.5%, Scorpio up 16.5%, and Diana gaining 15.8%, according to S&P Global Market Intelligence.None of the three companies reported earnings last month, or anything else of note, for that matter.