When Dunlap Towing of LaConner, Wash., bought the James T. Quig a couple of years ago, they renamed her the Rosario. Now the good tug is getting a lot more than a name change. The boat, built in the late 1970s or early '80's, originally had a single engine installed but she had been designed with enough beam for a twin engine installation. She has been operated with a single 900 hp main but now she will get two Cummins KTA38 main engines to be operated at 800 hp each to nearly double the boat's output to 1,600 hp. The beamy 64 x 21-ft. boat can easily handle the two engines. With the beam carried well aft, Dunlap's operations manager…