Work: work is customer will first consider the problem, but for the device there is no specific value can be based on the amount of work, can only be estimated, and the same dredger per hour of work in different work environment is also different, so the dredge work design according to the specific site of mud viscosity and hardness, combined with previous working experience in the comprehensive consideration of flow concentration and estimate. Therefore, it requires technology to have enough mature experience in dredger production and operation.