Calypso

The CALYPSO piston-corer

General Description:

The Giant corer Calypso shown in Figure 1 was developed onboard the R/V Marion Dufresne. Calypso can be fitted with a tube up to 75 m in length. The corer is deployed with an Aramide cable (specially designed for oceanographers with non-rotational technology), which is virtually weightless in water. In one of the Marion Dufresne trips Calypso had a sediment recovery of 64.4 m setting a new world record.

Figure 1: Components of the Giant Corer Calypso

To understand how Calypso works it is very important to notice the components of the corer shown in Figure 1. The corer consists of a trigger (piston), weight (~7 tons), corer pipes (metal tube with transitions), core catcher and four cables: main cable (from the corer to the ship), counterweight cable and the connecting cable between the corer tube and the piston (extra cable showed in top of the weight),i all of which are shown in Figure 1.

Procedure to Obtain the Marine Sediment Sample

Figure 2 is a simple demonstration of how the giant corer Calypso works. The mechanics of the corer are very easy to understand. The steps of the procedure to obtain the marine sedimentary sample are the following:

Descent: The corer is slowly put it into the sea and starts the descent. The descent of the corer is very slow; sometimes it take two hours just to hit the bottom of the ocean.
Releasing: The counterweight hit the bottom of the ocean, thats the beginning of the corer mechanism to obtain the sample. After the counterweight hit the bottom of the ocean the trigger is activated and the corer is released.
Fall: After releasing, the corer will fall at g-speed (gravitational force) and will get to the surface of the bottom of the ocean.
Penetration: With g-speed the core catcher will penetrate the soft marine sediment at the bottom of the ocean.
Extraction: After the sample is taken the giant corer Calypso is extracted very slowly.

Figure 2: Taking the Sample from the corer

After the giant corer Calypso is extracted from the sea, the marine sediment sample is in a plastic pipe, called a liner, inside the corer pipes. This liner is extracted and cut it into pieces of 1.5 m long and labeled. Each one of the 1.5 m samples are cut horizontally into two pieces. One of the two pieces is used for archiving and the other is used to do the measurements needed. The sample will be scanned to get an image before the sample is analyzed. The general properties of the sediments will be measure by the Multi System Track (MST), which measures p-wave velocity and amplitude, density, impedance and magnetic susceptibility. After the general properties are determined the core sample is cut it into stratigraphic sections depending the age of the sediments.

Storage of coring pipes.
Bringing the core back.
The core on board (after extracting the PVC pipe from the casing).

Control desk of the coring system.
Rolls of kevlar cable.
Winch for the kevlar cable.

Kevlar cable coming out on the back deck.
Kevlar cable out to sea...
Bringing the pipe onboard

Storage of coring pipes.	Bringing the core back.	The core on board (after extracting the PVC pipe from the casing).
Control desk of the coring system.	Rolls of kevlar cable.	Winch for the kevlar cable.
Kevlar cable coming out on the back deck.	Kevlar cable out to sea...	Bringing the pipe onboard