Robert Allan Ltd. has been awarded a contract to design a new version of the successful Z-Tech® 4500 tugs for the United States Navy (USN). The USN already has six vessels of this design, known as the YT 802 Class, in service. This first group were delivered between 2010-2012 and are in use in the Pacific Northwest and Japanese waters. Four new tugs (with an option for two more) will be built in Anacortes, WA by Dakota Creek Industries Inc. The hull form for the new vessels will be essentially identical to previous versions of this Class of vessels, but with deckhouse changes to suit new EPA Tier IV engines, which require significantly larger exhaust emission systems. Changes to the fendering system will incorporate feedback from operators on the existing vessels.