Design for Harbour fishing electrical crane

Customer: I need 4 fishing electrical cranes to disembark the fishing vessels. Electrical power 380V 50 hz 3 phase, If possible telescopic crane : -Capacity 500kg up to 6.50 meters, Mini 3.00 meters.

 It would be better with a telescopic boom for the crane. Rotation 360° 500kg/max. I send a picture below. 

Show me different models of your range, thanks. We can have a boom méchanically adjustable but the winch motor must be electric with a cable which can withstand 500kgss up to 750 kgs if possible. 

Waiting for your reply CIF Nouadhibou or Nouakchott, Mauritania with full spécifications for 5 cranes. 360°for the rotation. 

RAMHOIST: we can make as the most similar as yours, would you tell me pillar (column) height and diameter, for telescopic boom (jib), except the max. length is 6.5m and the min. is 3m, do you have other request for size? 

Customer: Height of the column is approximately between 2.80 and 3 meters according to the models. For the diameter, it depends on the resistance calculations for the type of steel, you have to determine yourself. 

RAMHOIST:  we can make as your request 4500 USD/unit (either of the two port with this price). the specification is what you send me before, we can make fully reach your requirment 

Another electrical power possible : 220V,  is it 3 phase or 1 phase?

Customer: Thanks for the offer, You may specify for 380V, 3phase 50 Hz.

3kw for the engine power seems enough, what is your technical choice ?

RAMHOIST: 2.2 KW is enough, below is the draft drawing we design:

RAMHOIST: The initial proposal convinces me but you have to continue in detail now and to push the power to 1 ton if possible.  Final technical specifications are welcome especially on the steels used. 

We can push the power to 1Ton but price is 1000 USD higher (need use bigger motor and stronger structure), below is based on 1TON.
Function: Hydraulic and Electric rotation, lifted by electric motor, the angle of jib is adjusted by hydraulic and electric system, Stretched out and drawed back is adjusted by hydraulic system.
Main material: 100 * 150 Rectagular steel tube
                        100 * 100 Square steel tube
                        80 * 80 Square steel tube
                        Φ 168 * 10 Seamless steel tube 
                        20mm steel plate for bottom

Customer: I have seen the plan but I do not find the hydraulic pump which must have an electric motor and a double-acting distributor with two controls. However It is clear for the winch. 

RAMHOIST: