PURPOSE: To enable a lifting action higher in the stroke as compared with the overall length of a tower by separately engaging vertical direction racks provided inside and outside a support tower for a working equipment for improving subsoil of the sea bottom with respective drive pinions provided on a working ship and the working equipment.
CONSTITUTION: The first vertical direction rack provided outside a support tower 1 adapted to support and guide a working equipment for improving subsoil of the bottom of sea or the like is engaged with a drive pinion 5 of a tower lift 4 arranged on a working ship 2 to support the tower 1 liftably on the working ship 2. The second vertical direction rack 3B provided inside the support tower 1 is engaged with a pinion 9 of a driver 8 arranged on the working equipment 6 to support the working equipment 6 liftably on the tower 1. This enables lifting action about twice the overall length of the tower 1 thereby simplifying the entire construction.
ISHIGA YASUMASA
KATOU SEIJI
