A New Escort Tug Family Designed to Anticipate New Safety Requirements and Operational Needs

The aim of the paper is to describe an industry-academic collaboration to conduct a research project whose main goal is the design of a new escort tug family characterized by high intact/damage stability margins, good maneuvering capability and stable behavior during escort indirect assistance. The project is focused on three main research areas: hydrodynamic design and internal subdivision of the hull, simulation of the escort capabilities in different operational scenario, development of control logics that will allow autonomous or unmanned operations. The paper describes the methodological approach adopted for the design and will show some preliminary results. The tug has been designed to be in compliance with new amendments of the 2008 Intact Stability Code (Res. MSC.415(97)) which will enter into force on 1st January 2020) both for towing and for escort operations. Furthermore, a significant step towards enhancement of ship's safety is granted by tug's capability to withstand a damage in accordance with criteria applicable to OSVs. This paper describes the prototype hull and its stability characteristics. CFD calculations and towing tank tests have been performed in order to assess the hull design and to infer simulation models able to describe the behavior of a family of vessels. In particular, the propulsion and maneuverability aspects in escort operations are deeply investigated. Results of the project will form the bases for the conceptual application to a remotely controlled or autonomous escort tug.