New RAscal Tug For United States Navy

December 11, 2019

Robert Allan Ltd. has been awarded a contract by Modutech Marine Inc. of Tacoma, Washington to design a new version of the commercially successful RAscal 1800-Z tugs for the United States Navy.

This award builds on the success of Robert Allan Ltd.’s Z-Tech® 4500 design for the US Navy which currently operates six, identified as the YT 802 Class, and has another six tugs, identified as the YT 808 Class, currently under construction.

The new RAscal tug (with an option for one more) will be built by Modutech Marine Inc at their facility in Tacoma. Known as the YT 815 the tug will be very similar to ten RAscal 1800-Z tugs which have been built by Sanmar Shipyards in Turkey and already delivered to commercial clients in UAE, Turkey, Spain, and New Zealand.

The design for the US Navy will include updates to suit new EPA Tier 4 engines and associated systems, extensive fendering above and below the waterline to handle US Navy surface ships, submarines and barges as well as incorporating feedback from operators of the existing Z-Tech® 4500 tugs. Wherever possible commonality in arrangement and systems to the existing Navy’s tugs Z-Tech® 4500 tugs is being utilized to minimize training hours. The tugs are configured essentially as “day-boats” but also provide accommodation for a crew of up to four persons. Construction of the first tug is to commence in 2020.

The new tug will have the following particulars:

  • Length Overall: 19.2 m (63’-0”)
  • Beam, Molded: 9.4 m (30’-11”)
  • Depth, Molded: 3.5 m (11’-6”)
  • Power: 2 x 970kW (2 x 1,300 hp)
  • Bollard Pull: 30 metric tons minimum

For more information on these or any of the RAscal family of high-performance tugs, please contact us at