A boat roughly 7 to 12 m long equipped with a hull- or pole-mounted echo sounder, GNSS-aided motion sensor, sound speed gear and an acquisition station. Launches work the shallow and inshore parts of a survey where the ship cannot go, and many are lowered from davits on the survey ship each morning and recovered at night. A typical crew is a coxswain plus one or two survey technicians.
Both survey launches are in the water by 0730, Launch 1 on the inshore block and Launch 2 on crosslines.
Also heard as
- launch
- hydro launch
- survey boat
Related terms
Hydrographic survey
A systematic measurement of depths, seabed features and shoreline, made so the results can be charted and trusted by mariners.
Pole mount
A sonar transducer fixed on a rigid pole over the side or bow of a boat instead of built into the hull.
MBES
Multibeam echo sounder: a sonar that measures a fan of depths across the track on every ping, covering a wide swath.
Weathered out
Unable to survey because wind, sea or swell would ruin data quality or make boat work unsafe.