This technical note presents charts and a table available for the design of ejector-pumps which can be used for the great depth dredging. Calculations are made in the following ranges:
　a) Ratio of the cross sectionl area of nozzle to that of the throat Aj/Ad=0～0.1
　b) Ratio of the cross sectional area of the throat to that of the outlet Ra=0.2～0.01
　c) Head of ejector-pump Hs=0～200m
　d) Pressure of water for driving ejector-pump Pj=10～100kg/cm2
　e) Suction velocity of ejector-pump Vs=3～6m/s
　f) Specific weight of the sucked soil-water mixture Gs=1.1～1.4ton/m3