Abstract: In a material transfer system, material from an excavation is drawn into a vessel by suction from a vacuum source. The vessel has discharge flaps at the bottom that are held closed by the suction. When the weight of the material in the vessel reaches a predetermined value, the flaps open and the material is discharged from the vessel. After the discharge, counterweights almost close the flaps and the suction seals the discharge flaps so that additional material is drawn into the vessel. The vessel includes a vibratory section and has sides that slope outwardly from top to bottom. The material entering the vessel contacts the vibratory section at a predetermined angle and is redirected to the discharge flaps without any caking on the vessel walls. The opening through the discharge flaps is larger than the inlet through which the material enters the vessel so that objects entering the vessel are discharged.

Abstract: An adaptive riser angle position reference system and method for determining the horizontal position of a marine vessel relative to an underwater wellhead from angular deviations from vertical of a riser between the vessel and the wellhead are disclosed. The system comprises sensors for determining deviation from vertical of the riser at positions proximate the wellhead and the vessel and a compensation filter for adaptively filtering signals indicative of the lower and upper riser angles in accordance with filter coefficients which are determined by riser parameters. The filter coefficients are established by riser parameter identification means which effectively compares riser response, as indicated by the lower and upper riser angles, with the responses of a plurality of riser models, and selects filter coefficients corresponding to the most accurate model.