This data set was acquired with a Sippican XCTD-1 XCTD Expendable Probe during Marcus G. Langseth expedition MGL1212 conducted in 2012 (Chief Scientist: Dr. W. Steven Holbrook). These data files are of Sippican MK21 Export Data File format and include Sound Velocity, Salinity, Temperature, and Conductivity data that have not been processed. Data were acquired as part of the project(s): RAPID: Collaborative Research: A Short, Open-Access 2D MCS Acquisition Program off Washington State and COAST - Cascadia Open-Access Seismic Transects, and funding was provided by NSF grant(s): N000141010175, OCE11-47762, OCE11-47841, OCE11-49095, OCE11-50628, and OCE11-53563.