Hopper dredgers

Motor dredger Jarif, beginning of the loading phase

Motor dredger Jarif, beginning of the loading phase

Costruzioni Navali started building motor ships for excavating and inert transportation at the beginning of sixties. First units, equipped with diggers, were extracting gravel from Po and Ticino rivers beds. As time went on, the massive request led to the construction of bigger and modern concept boats, equipped with dredging pump and cargo hold. Today the loading and unloading operations are steered by a PLC panel which energizes pumps, clutch, valves and other components, according to the selected working program. In addition to facilitate the tasks of the operator, the system protects the ship machinery from damage caused by a wrong use; for example, it is impossible to insert the clutch of the dredging pump if the diesel engine is not at a low engine speed or to operate the hydraulic gates if the lubricating - washing system does not have the correct pressure.
Costruzioni Navali built hopper dredgers with capacity up to 1600 m3, authorized to navigate on international coasts.

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Motor ship for river excavating

Motor ship for river excavating

Hydraulic digger installation

Hydraulic digger installation

Dilution system for dredgers with flat hold

Dilution system for dredgers with flat hold

Hopper dredger Jarif – prow part

Hopper dredger Jarif – prow part

Jarif – installing the prow part

Jarif – installing the prow part

Jarif – installing the bridge/quarters part

Jarif – installing the bridge/quarters part

Suction line dn 600<br> 

Suction line dn 600
 

Flanged articulation for suction lines

Flanged articulation for suction lines

Suction box with water-jet system

Suction box with water-jet system

22/24 pump installed on board

22/24 pump installed on board

Beginning of the loading phase

Beginning of the loading phase 

Water-jet pump

Water-jet pump

Tests on sea

Tests on sea

Isabella d’Este – propulsion groups

Isabella d’Este – propulsion groups

Loading channel

Loading channel

Computerized control pannel

Computerized control pannel

Control pannel

Control pannel

Motor pump group with transmission belts

Motor pump group with transmission belts

Dredging pump room<br> 

Dredging pump room
 

Spare parts stock:pulley with 16 grouves

Spare parts stock:pulley with 16 grouves

Spare parts stock:hydraulic gates

Spare parts stock:hydraulic gates

Spare parts stock: 14/12” complete pump

Spare parts stock: 14/12” complete pump

Inerts transformation system

Inerts transformation system

Sieve/drain group<br> 

Sieve/drain group
 

The hopper dredgers (used in internal waters or limited floors) are generally equipped with hydraulic propulsion groups which can adjust the propeller’s position according to the draft of the ship; no ballast is to be used and the dredger is kept perfectly in horizontal position. As a rough indication, a dredger with capacity of 500 mc has only 80 cm draft when empty and 2.4 meters at full load.
A special attention is reserved to the sieve system design; it has to treat dredged material without slowing down the unload operations which take approximately 40 minutes for 600 mc of sand (with 14/12” pump).

Hopper dredgers

Image Name Year Length Width Height Tonnage Mix capacity Dredging pump Test
Motor dredge “Jarif” Jarif 2002 82 m 12 m 5,10 m 1.500 t 5.600 mc/h 24/22" RINA
Motor dredge “Isabella d’Este” Isabella d’Este 1998 60 m 9 m 2,40 m 1.000 t 1.600 mc/h 14/12" RINA
Motor dredge “S. Patrizia” S. Patrizia 1997 50 m 8,50 m 2,40 m 550 t 800 mc/h 10/8" RINA
Motor dredge “Ca. Ma. I” Ca. Ma. I 1996 55 m 8,50 m 2,40 m 800 t 1.600 mc/h 14/12" MTCC
Image not available Alessandra 1996 50 m 8,50 m 2,40 m 550 t 1.200 mc/h 12/10" RINA
Motor dredge “Lidia Maria” Lidia Maria 1995 50 m 8 m 2,40 m 800 t 1.200 mc/h 12/10" MTCC
Motor dredge “Amelia” Amelia 1993 60 m 8 m 2,40 m 750 t 800 mc/h 10/8" MTCC
Motor dredge “Ghibli 3” Ghibli 3 1988 50 m 9 m 2,40 m 1.000 t 1.200 mc/h 12/10" MTCC
Image not available Ghibli 2 1982 45 m 8 m 2,40 m 480 t 800 mc/h 10/8" MTCC

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