It’s critical to data accuracy that sound velocity is applied during post processing. Rhys Davies, our Senior Surveyor discusses the two types of probes that iXblue uses.
The first is a portable system – dubbed the ‘mini svp’ which is hooked up to a line and lowered by hand to the sea floor to measure temperature and depth, before being pulled back up. This is suitable for use on smaller boats in shallow still waters, and the vessel must be completely stopped for the mini svp to be deployed.
On bigger boats, in deeper waters, we use an ‘underway sound velocity system’ which can be used whilst the boat is in motion, and saves time and cost.
See our post The Three Things Which Affect Sound In Water for further discussion on the sound velocity probes and the reason why we always use them.