Portal Slewing Crane
A portal slewing crane is the machine that works the quay itself. It travels on rails laid along the berth, turns through a full circle and reaches out over the water, so the cargo comes off the ship where she lies and the same hook puts it on a truck, a barge or a stack. The reach is the point of it: how far out over the water the crane has to work is what decides the jib, and the berth is what decides the rail gauge. We supply the MQ series in single-jib and four-bar level-luffing form, from 10 to 40 t with 25 to 35 m outreach.
- Capacity10, 16, 25 and 40 t
- Maximum outreach25, 30 and 35 m
- Jib typeSingle jib, or four-bar level luffing
- ModelsMQ1025 through MQ4035
- StandardsDIN, FEM, IEC, AWS and GB
- SlewingFull circle
Single jib, or four-bar level luffing
The jib is what separates one portal crane from another, and there are two forms to choose between.
Single jib. The jib is pinned at the base and luffed by rope: simple, few moving parts, and lighter for a given lifting capacity, which is why heavy-lift machines are usually built this way. It also has the largest capacity for its size. What it does not do is keep the load level while the jib moves.
Four-bar level luffing. A combined jib system — jib, balance beam and tie rod — arranged so the load travels almost horizontally as the jib luffs. That matters when the crane is working a hatch: the load can be brought from the hold out over the quay at a steady height instead of being lifted and lowered to compensate, which cuts the luffing power and the cycle time, and the drop is small enough for careful positioning.
Both handle general cargo, bulk and containers. Which one you want depends on how much luffing you do under load: a machine that sets its jib once and then hoists suits a single jib; a machine that works a hatch all shift is usually better with four-bar.
Quays, yards and transfer berths
Portal slewing cranes are the standard machine wherever cargo has to move between ship and shore: ports, river quays, container and general-cargo berths, and the stockyards behind them. The same crane unloads a vessel, swings through the circle and puts the load on a road vehicle, a rail wagon, a barge or the ground — which is why the type survives against more specialised cranes.
General cargo — steel, timber, project pieces, palletised goods, lifted on the hook or with a spreader.
Bulk — sand, gravel, coal, fertiliser and grain with a grab; grab duty is heavier than hook duty, so the duty classification and the brakes are specified for it rather than assumed.
Containers — with a spreader, at the modest throughputs where a full container crane cannot be justified.
Five things that decide the machine
- The berth. The rail gauge is not a free choice — it has to match the rails already on your quay, or the rails you are prepared to lay. Send the gauge and we confirm the wheel base and wheel loads.
- The vessel. Beam and freeboard set how far the jib has to reach and how high the hook must travel. Lifting height above and below rail follows from the tidal range and the hatch.
- The load. The heaviest single piece matters more than the average. A crane rated 16 t at 30 m will lift less at 35 m — the capacity curve is not flat, and we quote the curve, not one number.
- The duty. Casual berth work and two-shift continuous handling are different machines: the gearboxes, brakes and the duty classification are sized from your handling rate, not from the lifting capacity alone.
- The supply. Tell us the voltage, frequency and how you want the machine fed — cable reel, conductor rail or trailing cable — and whether you want a diesel-electric set for a berth without a reliable shore supply.
Built to standard, tested before dispatch
The design, manufacture and inspection of the MQ series follow DIN, FEM, IEC, AWS and GB standards, together with the current national standards. Those are the buyer's protections, not marketing: they fix how the structure is calculated, how the duty classification is applied, how the electrical installation is wired and how the welds are made and inspected.
We are a supplier, not the factory: your crane is built by one of our long-term partner factories in Changyuan, and we tell you which one. That is exactly why the inspection step exists — we watch the machine being built and tested rather than forwarding a catalogue.
- Approved drawing before steel is cut: outreach and capacity curve, rail gauge, wheel loads, lifting heights and the clearance envelope, so your quay engineer can check the wheel loads against the structure first
- Structure and welds checked against the drawing, with weld inspection to the level the standard and your inspector require
- No-load and rated-load test: travel, slewing, luffing, hoisting, and every limiter demonstrated; overload limiter set and recorded
- Brakes and safety devices measured and proven on the machine, not on a data sheet
- Photographs and video of the test and of the loading, sent before the container is sealed
- Documents in the container: packing list, product certificate, test report, O&M manual, erection and electrical drawings
Specification range
| Models | MQ1025, MQ1030, MQ1625, MQ1630, MQ1635, MQ2525, MQ2530, MQ2535, MQ4025, MQ4030, MQ4035 |
|---|---|
| Capacity | 10 t, 16 t, 25 t and 40 t |
| Maximum outreach | 25 m, 30 m and 35 m |
| Jib type | Single jib (simple, lighter, highest capacity for its size) or four-bar level luffing (load travels horizontally) |
| Slewing | Full circle |
| Standards | DIN, FEM, IEC, AWS and GB, with the current national standards |
| Rail gauge | Matched to the rails on your quay — send the gauge and we confirm the wheel base and wheel loads |
| Lifting height | Above and below rail, set by your berth, tidal range and vessel size |
| Duty classification | Sized from your handling rate rather than assumed; heavier for grab duty |
| Attachments | Hook as standard; grab, container spreader or C-hook on request |
| Supply | To your quay supply — tell us voltage, frequency and how the machine is to be fed |
| Control | Cabin as standard; radio remote available |
The table shows the range we normally supply. Your offer states the exact capacity, span, lifting height, duty class and voltage for your site — and where a figure in this table differs from the offer, the offer prevails. Send us your requirement and we will confirm each line in writing before you order.
Portal Slewing Crane: questions we are asked
Single jib or four-bar — which do I need?
Look at how much luffing you do with a load on the hook. A machine that sets its jib once and then hoists suits a single jib: fewer parts, lighter, and the most capacity for its size — which is why heavy lifts are usually single jib. A machine that works a hatch all shift, bringing the load in and out at a steady height, is better with four-bar level luffing: the load travels almost horizontally, less power goes into luffing, the cycle is shorter and the load does not have to be raised and lowered to compensate. Tell us how you expect to work and we will recommend the simpler one when it is the right answer.
How do I read the model number?
The two numbers are capacity and outreach: MQ1630 is 16 t at 30 m maximum outreach, MQ4035 is 40 t at 35 m. Note that capacity falls as outreach increases — the rated capacity applies at the outreach in the model name, and the crane lifts less further out. We quote the capacity curve for your machine rather than a single figure, so you can see exactly what it lifts where you need it.
What do you need from me to quote?
The rail gauge already on your quay (or the gauge you plan to lay), the highest and lowest water levels, the largest vessel you will work and her beam, what you are handling and the heaviest single piece, how many hours a day the crane runs, and the electrical supply available on the quay. With those we can put a model and a price in front of you, together with the wheel loads your quay engineer needs to check the structure.
Can it work with a grab for bulk cargo?
Yes, and for aggregate, coal, fertiliser and grain it usually does. Grab duty is harder than hook duty — a heavier attachment, more cycles, more dust and impact — so the duty classification, the brakes and the trolley protection are specified for grab work rather than defaulted. Tell us the material and the tonnage per hour and we will size the machine for that, not for a catalogue figure.
How long is delivery, and who erects it?
A portal crane is a site-erected machine: it arrives in transport sections and is assembled on the quay with a mobile crane, typically over several weeks depending on size and site access. We supply the erection drawings, the bolting and welding method and the lifting points, and we can send a supervisor for the assembly, the load test and operator training, quoted separately so you can see what it costs. Manufacturing time is quoted against the approved drawing rather than promised before it exists.
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Supplier, not factory — and we say which factory
We quote from 4–5 long-term partner factories in Changyuan, Henan. You will know which one is building your crane, our inspectors test it before shipment, and the drawings, test report and manuals travel with the machine. More about how we work →