Cruise ID: R/V Rachel Carson Multibeam System: EM2040 Dates: March 21-22, 2024 Executive Summary R/V Rachel Carson (RC) received a major update to its mapping systems during the 2023-24 shipyard period: New Kongsberg EM2040 (0.4° TX / 0.7° RX) New Seapath 380 navigation system with a MRU5 Comprehensive new survey of vessel and sensor offsets by Westlake Consultants The MAC was asked to assist with conducting Sea Acceptance Testing (SAT) of the new EM2040 using the Seapath; due to schedule constraints, the MAC provided remote support from shore for planning and data processing after the SAT; the on-board mapping team included SSSG personnel with multibeam experience and a Kongsberg field engineer (Tony Dahlheim) who completed the Kongsberg SAT contract procedures A number of EM2040 test sites occupied previously by NAVO vessels were prioritized for planning, as the publicly available seafloor data in Puget Sound is often not sufficiently detailed for