SQ2ZA2T Marine Crane on an Aluminium Workboat in China

A yellow knuckle boom crane with a wire rope winch on the column, fitted at the front of the cabin on an aluminium workboat cruising in a harbour: photos and videos from our customer in China show a BOB-LIFT SQ2ZA2T marine crane during fitting and on the water.

At a glance: SQ2ZA2T 2 t knuckle boom marine crane · China · aluminium workboat · 2 customer photos and 2 videos.

What the photos and videos show

• The fitting. Both videos were filmed in a boat workshop. The crane stands on its square base plate on the bare aluminium deck of the new hull, with life rings and life jackets piled beside it.
• The crane. The yellow boom carries the BOB-LIFT logo, the model mark SQ2Z and the warning NO STANDING UNDER THE BOOM! A winch drum with wire rope sits on the column.
• The test. A worker at the control levers raises the boom upright, then folds it down while the camera follows the hoses and cylinders along the boom.
• On the water. Two photos show the finished boat under way in a harbour, with the crane folded in front of the cabin and tower cranes on the shore behind.

These are the customer's own photos and videos. No load weights or comments came with them.

About the SQ2ZA2T

The SQ2ZA2T is an earlier 2 t knuckle boom marine crane. It is no longer in the current range, and the technical department has no current drawing for it, so this record does not quote load figures for it. For a new crane of this size, see the 2 t knuckle boom marine crane page, where each current model has its own dimension and load chart drawings.

Lifting moment is the load times its distance from the slewing centre. That is why the rated load drops as the boom reaches out. For example, a load the crane lifts easily close to the column can be too heavy once the extension is pushed out. Working radius is the level distance from the slewing centre to the hook. On a vessel or a quay, the pedestal takes the place of outriggers. It must be strong enough for the crane's weight and its full lifting moment. For general crane safety rules, see the OSHA cranes and derricks standard.

On a small workboat, the crane often sits in front of the cabin, so the skipper can see the load and the boom can reach over the bow and both sides. A 5 t telescopic marine crane works in our delivery record from the Maldives, and a 6.3 t marine crane stands on a vessel in our record from Chile.

Fitting a crane on an aluminium boat

A light hull needs more care than a steel deck when a crane goes on board. Four points to plan for:

1. Spread the load. Fit the base plate on a doubler and frames under the deck, sized for the crane's full lifting moment, not on the deck plate alone.
2. Keep the metals apart. Use insulating pads and sleeves between steel bolts, the steel base and the aluminium, so sea water does not start galvanic corrosion.
3. Check the trim. The crane and its load sit high and far forward. Check that the boat still floats level with the heaviest load out at full radius.
4. Test before launch. Run every motion and the winch in the workshop, as the videos show, before the boat goes in the water.

Sea water is hard on steel, so the marine cranes get an epoxy zinc primer with a polyurethane acrylic top coat. Other sizes are in the knuckle boom marine crane range, and the marine crane buying guide covers mounting in more detail.

What to send us for a marine crane

To match a current crane to your vessel, we need a few details. Short answers are fine.

• The site. The vessel type and length, or the quay, and where the crane will stand.
• The lifts. The heaviest load, and how far from the crane it is picked up and set down.
• The power. The hydraulic power pack you have now, or whether you need a new one.

If you run an SQ2ZA2T today, a photo of its nameplate helps too. Send these through the contact page, and our team will check reach and load against the current load charts.

Record compiled by Achord Chan, Product Operations Director at BOB-LIFT, from the customer's photos and videos.