6.3 Ton Knuckle Boom Marine Crane

Where the 6.3 ton SQ6.3ZA4T fits

The SQ6.3ZA4T has no winch, so loads hang from the boom hook: that suits deck cargo, barge work and quay handling where the lift stays above deck level. With a self weight of 1,680 kg and a 680 × 680 mm base plate, it suits supply boats, barges and quays that move drums, pallets, small machinery and deck equipment.

Rated capacity always depends on radius. At 6.3 m the SQ6.3ZA4T lifts 2,020 kg and at 8.3 m it lifts 1,500 kg, so check the weight of your heaviest regular load at the distance you need before you choose a tonnage.

We size a marine crane by the load and the radius you need, not by vessel length. Send us the heaviest load, the furthest point it must reach and a deck drawing, and we check them against the SQ6.3ZA4T load chart.

Load at each radius

Figures from the SQ6.3ZA4T load chart with the boom horizontal. Do not lift more than the chart shows at your working radius. Download the SQ6.3ZA4T load chart (PDF)

Deck mounting dimensions

These figures come from the SQ6.3ZA4T dimension drawing. Your shipyard or naval architect designs the pedestal and the deck reinforcement for the crane’s 1,680 kg self weight and its 13.2 t·m maximum lifting moment.

We can adapt the mounting to your vessel’s deck, for example by changing the pedestal height. Download the SQ6.3ZA4T dimension drawing (PDF)

Corrosion protection for sea duty

The T in SQ6.3ZA4T marks the marine version, which receives a multi-layer anti-rust treatment for salt air and spray. How long a crane lasts in a harbour still depends on routine care: rinse it with fresh water after salt-water work, grease the slewing bearing and pins on schedule, and check hoses and fittings for corrosion.

Warranty and service

BOB-LIFT covers the whole crane for 12 months. Common spare parts leave the factory within 48 hours, and our service team answers within 12 hours and can guide repairs by video. Cranes ship from Lianyungang, Qingdao or Shanghai.

All knuckle boom marine cranes · How to choose a marine crane

Where the 6.3 ton SQ6.3ZA4TJ fits

The SQ6.3ZA4TJ combines a 6,300 kg rating with a 10.2 m reach and a self weight of only 1,740 kg, less than our 5 t knuckle boom model. That ratio suits workboats, barges and small cargo boats where deck load is tight but reach matters. At full reach it still lifts 1,190 kg.

Need a longer, straight boom instead? Compare the 6.3 ton telescopic boom marine crane (SQ6.3SA4T).

We size a marine crane by the load and the radius you need, not by vessel length. Send us the heaviest load, the furthest point it must reach and a deck drawing, and we check them against the SQ6.3ZA4TJ load chart and the deck space it needs when folded.

Deck mounting dimensions

These figures come from the SQ6.3ZA4TJ dimension drawing. Your shipyard or naval architect designs the pedestal and the deck reinforcement for the crane’s 1,740 kg self weight and its 13.2 t·m maximum lifting moment.

We can adapt the mounting to your vessel’s deck, for example by changing the pedestal height. Download the SQ6.3ZA4TJ dimension drawing (PDF)

Corrosion protection for sea duty

The T in SQ6.3ZA4TJ marks the marine version, which receives a multi-layer anti-rust treatment for salt air and spray. How long a crane lasts in a harbour still depends on routine care: rinse it with fresh water after salt-water work, grease the slewing bearing and pins on schedule, and check hoses, fittings and the winch rope for corrosion and wear.

From our customers

Our Egypt case study follows SQ5ZA3T knuckle boom marine cranes from shipyard outfitting to a finished harbour workboat. See the Egypt workboat project

Customers in Russia and Chile have sent photos and video of earlier 6.3 t knuckle boom marine cranes (SQ6.3ZA3T and SQ6.3ZA4T). See their photos under Customer feedback

All knuckle boom marine cranes · How to choose a marine crane

Where the 6.3 ton SQ6.3ZA5T fits

The SQ6.3ZA5T is the long-reach option among our mid-size marine cranes. Its five-section boom reaches 12.2 m and keeps useful capacity out at radius: 2,020 kg at 6.3 m, 1,500 kg at 8.3 m and 1,190 kg at 10.2 m. Folded, it measures 2,407 × 870 × 2,252 mm. That suits supply boats, barges, pontoons and fish-farm service vessels that lift cages, nets, generators, tanks and stores across a wide deck or onto a quay.

If you do not need that reach, the BLZ90K4TJ sits on the same 680 × 680 mm base plate, is rated at 4,600 kg and reaches 9.75 m, at 310 kg less self weight. Send us the heaviest load, the radius it must reach and a deck drawing, and we check them against both load charts.

Load at each radius

Figures from the SQ6.3ZA5T load chart, with the boom horizontal. With the boom raised to 75°, the hook reaches about 14.5 m above the base. Download the SQ6.3ZA5T load chart (PDF)

Deck mounting dimensions

These figures come from the SQ6.3ZA5T dimension drawing. Your shipyard or naval architect designs the pedestal and the deck reinforcement for the crane’s 1,730 kg self weight and its 13.2 t·m maximum lifting moment.

We can adapt the mounting to your vessel’s deck, for example by changing the pedestal height. Download the SQ6.3ZA5T dimension drawing (PDF)

Corrosion protection for sea duty

The T in SQ6.3ZA5T marks the marine version, which receives a multi-layer anti-rust treatment for salt air and spray. How long a crane lasts on the water still depends on routine care: rinse it with fresh water after salt-water work, grease the slewing bearing and pins on schedule, and check hoses, fittings and the winch rope for corrosion and wear.

All knuckle boom marine cranes · How to choose a marine crane