Optimized Transit Tool & Easy Reference (OTTER) Improved Data Analysis

Abstract

The Optimized Transit Tool & Easy Reference (OTTER) program is a simple Excel tool designed to help surface ships reduce their fuel consumption during transits while still adhering to mission and operational requirements. Past studies have attempted to pin a precise number to the expected fuel savings made possible through OTTER, but this is difficult to do because of the highly variable nature of OTTER’s potential fuel savings. Possible fuel savings are a function of not only a ship’s mission, but also the base case behaviors to which the optimized transit solution is being compared, and the operational constraints that limit the potential optimizations. This effort expands on previous efforts by considering a wider range of possible transit scenarios for Cruisers and Destroyers. We modeled transits with an average speed ranging from 8 to 27 kts, with up to four hours per day dedicated to running drill sets, and both operational conditions where engine modes are unconstrained and where ships must maintain split plant at minimum. In all cases OTTER was shown to improve fuel efficiency compared to the bases case, but the improvements ranged from significant to negligible depending on specific operating and transit conditions. This effort also solicited feedback from Navy Surface Warfare Officers (SWOs) at the Naval Postgraduate School to get their input on the tool’s interfaces and training materials. Interviews with these SWOs led to revelations on how the OTTER interface can be improved to alleviate confusion and how the training materials can be made more effective. Their input will be used in future versions of OTTER and its related materials to improve the effectiveness of the tool and training materials once it reaches the users.