"> FINAL UNDERWATER CORE SAMPLER TESTS

CBR15 – when it took place

From 10 to 13 October the second test campaign of the remote-controlled vehicle for coralligenous sampling was carried out. Testing the ultimate updates has been the main objective of the campaign. During the last tests, done in July, several issues mainly regarding power supply emerged and caused frequent ROV power failure. These problems affected the whole test operation during which we were able to extract only one sample. Moreover, the lack of a protective frame for core carrel magazine caused some collisions between barrels themselves and coralligenous build-ups during the anchoring and the tool changing phase. Lastly, throughout post operation inspections, the corer frame main plate and the anchoring plate were found slightly bent due to mechanical stress during transport and core drilling.

Activities

In account of power supply problems, a 3 kW-3 Wh portable power station, with an expansion 3 Wh LiFePO4 battery has been used. The total capacity of this power station provides an autonomy of 2 hours at full power. In addition, in order to prevent any impact among core barrel and surrounding build-ups, an anodized aluminium plate has been installed beneath the barrel magazine. Eventually, both the anchoring plate and the skid main plate were replaced by new ones having double the thickness of the old ones. These actions have led to an increase of the vehicle weight (9 kg in air and 5 kg in water) requiring the ROV ballast removal.

During the entire campaign a faulty commercial cable penetrator caused water leaks in the core drill control electronics canister. Due to this, some of the device functions, as the “double tube” mechanism, have been disabled. Nevertheless, several sample operations have been carried out at depth ranging from 30 to 37 meters resulting in 5 core samples.

Figure 1 – Repair work on electronics canister
Repair work on electronics canister.
Figure 2 – One of the core sample brought to the surface
One of the core sample brought to the surface
Figure 3 – ROV on-board view during core operation
On-board view during core operation (ROV)
Figure 4 – ROV on the Marzamemi seafloar
ROV on the Marzamemi seafloor
Figure 4.1 – ROV on the Marzamemi seafloar
Floating in the blue (ROV)