SaVel part II

On Wednesday, SaVel operations continued onboard NRP Cassiopeia, collecting CTD data along the transect close to the navigation channel. As in the week before, it was a (very!!) long day for Xplore-1 and Xplore-2. Temperature, salinity, turbidity and chlorophyll data was taken during more than 12 hours in a place where the collision risk is very high.

Most of the plan went smoothly for both vehicles until the 7-hour mission. The LAUV Xplore-2 abort the plan due to a motor fail. The vehicle continued to send its position at the surface but the propellers couldn’t initiate. So, we needed to start a rescue plan for the Xplore-2…. However, the search was very easy and short. We found the vehicle close to a small boat where an old couple trying to pull a fishing rod complaining about something… Well, you can imagine what the result was. Their fishing line was completely tangled on the propeller and we needed to bring the vehicle onboard for a verification. Despite the bad luck, it was possible to release the fishing line from the propeller and launch the vehicle on mission again. That’s why we opted to use two vehicles at the same time in this mission. If something went wrong for one, we can fill the time gaps with data from the second vehicle.

The sea state was not like a mirror as in the first week but the conditions were good for the mission. The measured communication ranges were quite stable at 600m for Wi-Fi and more than 2.5 km for acoustic modem (Xplore-2).