One of the projects I worked on, was a 250mt Secondary Hydraulic Driven Crane. This completely hydraulic driven crane has a Safe Working Load (SWL) of 250mt on the main hoist. The main HPU and drum of the main winch are underdeck. A hydraulic swivel makes sure that the hydraulic power is also delivered to the whip and aux hoist, which are on the crane itself.
The crane has a main and whip hoist winch controlled by secondary hydraulics. The advantage of secondary hydraulics is the low inertia of the hydraulic motors (compared with electrical motors), which leads to accurate control of the load, especially during heave compensation.
As hydraulic engineer I started working on the project in the beginning of the engineering phase. This included making concept drawings (especially hydraulic diagrams), concept calculations on the parts, such as motors and pumps, which would be used and power calculations including a large piston accumulator to limit the power of the Hydraulic Power Unit (HPU). Afterwards the hydraulic design of the main wich and HPU was done by me. The top of the crane was done by another engineer, based on my concept calculations, due to the available time for this project.