Since coring techniques have not evolved much (empirical adjustments), coring on large seafloor areas with new cables requires new conditions for implementation and adjusting. Recent studies using special instrumentation set up on various mobiles parts of the corer and which analyzed the layers sampled showed that recovery can vary by a factor of 2, the sampled levels being located on different sides of the core sample (layer shape not well preserved) and the length of sediment disturbed by the piston coring is proportional to the depth of water and the corer's weight in the water. This can reach 20m for a 40m core at water depth of 4000m. The ESSCAR9 cruise(PGE02-PJE0202-E020204A1) had 3 main objectives to improve the core sampling technique: -Characterizing the deep water aramid cable to take account of the elastic recoil in order to adjust the height of the free fall and of the loop. -Testing various tricks to reduce the negative effects of the elastic recoil and preserve the sedimentary layers (using a piston with one-way valve, a diaphragm enabling water to flow through, a long nose cone and significant free fall length). A painted tube was also tested to see the effect of frictional resistance of sediment on the tube during penetration, to obtain the same penetration with lower ballast weight. -Understanding and modelling the kinematics for adjustments and tricks used to improve the rate and quality of sediment recovery in the core and provide graphs for operational teams. Twenty different configurations and adjustments were tested. A single parameter was changed to ensure that its influence was shown. For each configuration, core sampling was done twice to qualify the adjustment's reproducibility. Results obtained are applicable to RV L'Atalante, Beautemps-Beaupré, Pourquoi Pas? and Marion Dufresne.