R2Sonic 2026, Operation Manual

Page: 151 / 254

Page 151 of 254
Version 6.3 Rev r012
Date 05-11-2022
5.
Secure the bitter end of the downline to the vessel.
6. Request permission, from the bridge or helm, to deploy and await their OK to launch.
a. Bridge or helm to ensure that the vessel is out of traffic.
b. Bridge or helm to assess wind and sea conditions and advise as to which side of the
vessel the deployment should be made.
7. Put the probe in the water until it is totally covered and let it remain there for a period of
time to acclimate to the sea temperature. This is very important with a CTD type of probe,
but of less concern for a time-of-flight probe.
8. Verify the water depth.
9. Lower the probe at a constant rate; only the downcast should be used.
10. Try not to allow the probe to touch the bottom.
11. Recover the probe rapidly.
12. As soon as the probe is on deck, notify the bridge or helm that they are free to manoeuvre,
but remain in the area.
13. Rinse the probe with fresh water and dry thoroughly.
14. Download the cast and verify that it looks good.
15. Load the cast into the data collection software.
8.6.5.2 Deep Water Cast / Deployment by mechanical means
A cast in deeper water requires more preparation and planning. A deepwater cast can be
considered to be any cast that is deployed via an ‘A’ Frame, winch, or other mechanical means.
Even a shallow water cast can fall under this definition when mechanical means are used.
One of the main concerns, in a deep water cast, is that the probe will not go straight down due to
the current flow or vessel drift due to wind and/or currents. This being the case, weights must be
used to ensure the cable (and probe) go as straight down as possible.
Unless the sound velocity probe is designed to have an additional weight attached to it, no weights
should be attached to the sound velocity probe. The weights, which enable deployment as straight
as possible, are attached to the end of the cable. The probe should be attached to the cable
approximately 3 – 5 metres above the weights; if the weights hit bottom, this should provide
enough scope for the probe to land clear of the weights.