Castleman Maritime LLC, Clear Lake Shores, Texas, has designed a 110'x38'x17' tug class for Baltimore-based Vane Brothers. The new Assateague-class of ATB (articulated tug/barge unit) tugs has been developed using American Bureau of Shipping rules for a classed vessel, feature raised forecastles and will admeasure under 500 gt. Construction on three of the new tugs at Conrad Industries’ Orange, Texas, shipyard, began in December, only three months after design began on the vessels.

The tugs will be powered by two Cummins QSK-60 diesels driving open 4-bladed, 102", bronze propellers mounted on 9.5" shafts through Reintjes WAF 873 marine gears with 7.087:1 reduction ratios.

Two 125-kW Cummins generators and one 60-kW Cummins emergency generator will power the tugs’ electrical systems. The design features the Beacon Finland JAK-700 coupling system that will connect each tug to its 405'x74', 80,000-bbl. barge. Crew access to the barges will be accomplished via a Schoelhorn-Albrecht custom-made gangway.

Castleman Maritime’s president, Gregory E. Castleman, said that he is grateful for Vane's confidence in his company’s design capabilities. “I had sent some designs to Jim Demske [Vane’s senior port captain], and he liked my style of design,” Castleman said in a phone interview. “We met and talked. It’s been great. We’ve worked very closely together.”

Castleman said he’s also worked closely with designers at Bristol Harbor Group, Bristol, R.I., who designed the barges that the new tugs will be mated with to create the ATBs. “They’ve been great to work with,” he said. “The whole experience working with Vane and Bristol Harbor has been a really good one."

Castleman said the new tug class reflects 40-plus years of work in the design of many types of service craft, including tugs, barges, crewboats, and offshore supply vessels. The first tug, Assateague, is scheduled for delivery in August 2017.

Ken Hocke has been the senior editor of WorkBoat since 1999. He was the associate editor of WorkBoat from 1997 to 1999. Prior to that, he was the editor of the Daily Shipping Guide, a transportation daily in New Orleans. He has written for other publications including The Times-Picayune. He graduated from Louisiana State University with an arts and sciences degree, with a concentration in English, in 1978.