Ship heave over the course of operations at A. Hole U1356A, and B. U1361A. Heave is determined from acceleration measurements of the motion reference unit located near the center of the ship. Heave became too high for logging (or drilling) at U1356A, and during the FMS-Sonic deployment at U1361A, high heave made bringing the tools up through the pipe to the ship a very slow process.