The Seafloor DMT is a penetrometer for advancing the DMT, the SDMT and the Medusa DMT with multiple short length strokes (0.10 m or 0.20 m). It is very cost-effective compared to competitive devices because it does not require to advance the probe at a specific speed (2 cm/s for CPT). A first prototype was built and tested, but the system is still at a development stag.
The seafloor dilatometer has been developed to execute DMT soundings from the seabed. It is composed by an upper pushing section, whose weight is 60-80 Kg, easily transported, and a lower heavy section, that can be ballasted 3 to 7 tons, easy to construct locally. The two sections can be quickly solidarized using 4 bolts. The seafloor dilatometer can operate up to a waterdepth of 100 m. The maximum test depth depends on soil consistency – it is the depth penetrable with 7 ton push. Six or seven pushrods are already charged vertically on top, before lowering the machine. More rods can be added by keeping the string vertical, sustaining the rodstring with a buoy – or a trestle fixed to the top of the ballast.