With the HMT system a large number of parameters are continuously measured on each dredging vessel of a project. Using short intervals (2 to 10 sec) the measurement covers the total project duration from the beginning to the end and provides a sound information on all physical processes involved.As many parameters of this system are interdependent the evaluated results have a high level of reliability. To further increase the operational safety a redundant measurement method is employed. As the production and the survey procedures are measured simultaneously, all dredging activities can be linked to the respective location.