US-based Crowley Holdings has unveiled designs for the sixth heavy-lift deck barge for its fleet, the 455-6, which is scheduled to be constructed and operational by 2013.

The boat is the third heavy-lift deck barge the company has planned this year.

The 455-series deck barges with 25ft side shells can accommodate large drilling and production units deployed for deepwater offshore energy development and exploration. They supply deck strength for loads up to 4,200lb a square foot.

Crowley is also scheduled to deliver the 455-7 deck barge in September and the 455-8 at the end of the year, bringing the total number of heavy-lift deck barge deliveries in 2009 to five.

Crowley offers diversified transportation and logistics services in local and global markets through six operating lines of business.