A bunker boat is a purse seiner after menhaden (AKA bunker, pogy, alewife, shad). The fish is use in animal feeds, fertilizer, paint, cosmetics, and its oil has commercial value, It's not a human food fish. The Atlantic seaboard is the largest fishery and a huge fleet of these boats, all architecturally similar, were maintained there. Some sources call the menhaden catch the most important commercial catch in American waters.
The plans for this model are loosely drawn after the Helen Euphane, a 114 foot 293 ton steam powered example of the type. She was built in 1902, and served temporarily in both world wars in the Coast Guard, as a minesweeper and patrol boat. The last history I have of her is from the 50s, at which time she was still working the fishery.
Cheers,
Ed-