4.6 Ton Knuckle Boom Marine Crane

Where the 4.6 ton BLZ90K4TJ fits

The BLZ90K4TJ is the compact option in the 4–5 t knuckle boom class. Its three-section boom reaches 9.75 m, and it keeps more capacity out at radius than a longer boom of the same moment: 1,525 kg at 6.09 m and 1,140 kg at 7.9 m. That suits workboats, landing craft and fish-farm service vessels that lift nets, tanks, engines and stores close alongside, where deck space and topside weight matter more than extra reach.

If the load has to travel further, the sister model BLZ90K5TJ has the same 90 kN·m rating and a four-section boom that reaches 11.7 m (590 kg there), at 100 kg more 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 BLZ90K4TJ load chart, with the boom horizontal. With the boom raised to 84°, the hook reaches about 11.9 m above the base. Download the BLZ90K4TJ load chart (PDF)

Deck mounting dimensions

These figures come from the BLZ90K4TJ dimension drawing. Your shipyard or naval architect designs the pedestal and the deck reinforcement for the crane’s 1,420 kg self weight and its 90 kN·m maximum lifting moment.

We can adapt the mounting to your vessel’s deck, for example by changing the pedestal height. Download the BLZ90K4TJ dimension drawing (PDF)

Corrosion protection for sea duty

The T in BLZ90K4TJ 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

Where the 4.6 ton BLZ90K5TJ fits

The BLZ90K5TJ is the long-reach option in the 4–5 t knuckle boom class: four boom sections reach 11.7 m and still lift 590 kg there. That reach suits quays, barges and work pontoons where boats moor a few metres away, or vessels that load cargo across a wide deck. It is rated at 4,600 kg at 1.9 m and weighs 1,520 kg.

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 BLZ90K5TJ load chart and the deck space it needs when folded.

Deck mounting dimensions

These figures come from the BLZ90K5TJ dimension drawing. Your shipyard or naval architect designs the pedestal and the deck reinforcement for the crane’s 1,520 kg self weight and its 90 kN·m maximum lifting moment.

We can adapt the mounting to your vessel’s deck, for example by changing the pedestal height. Download the BLZ90K5TJ dimension drawing (PDF)

Corrosion protection for sea duty

The T in BLZ90K5TJ 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.

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