A marine crane is any crane built to work on a vessel, barge, pontoon or quay in a salt-water environment. An offshore crane is a specialised kind of marine crane, designed and certified for lifts on or between offshore installations and supply vessels in open sea. The offshore crane is rated against wave height, built to an offshore standard such as API Spec 2C or EN 13852-1, and normally verified by a third party. Every offshore crane works in a marine environment, but most marine cranes are not offshore cranes.
We have manufactured hydraulic cranes in Xuzhou since 2003, including knuckle boom and telescopic marine cranes for workboats, cargo vessels, barges and quays. Our marine cranes have no class-society certification and are not offshore cranes, so this guide is written from the side of the line where we work. It explains where each type is used, why waves change the engineering, which standards and records apply, and how to tell which one your project needs.
Key takeaways
- “Marine crane” is the broad family: deck, ship, boat, barge and quay cranes. “Offshore crane” is the narrow, specialised member that serves platforms and supply vessels at sea.
- An offshore crane’s load chart depends on significant wave height. Higher waves mean a lower safe working load.
- Lifting from a moving supply boat is the hardest case. A badly timed hoist can load the crane with up to three times the weight being lifted.
- Offshore cranes follow offshore standards (API Spec 2C, EN 13852-1) and carry extra safety systems such as automatic and manual overload protection.
- On US fixed platforms, 30 CFR 250.108 requires API Spec 2C cranes, API RP 2D operation, a working anti-two-block device and kept records.
- For harbours, rivers and sheltered coastal water, a hydraulic marine crane is usually the right tool. BOB-LIFT makes these, from 0.8 t to 25 t, but not offshore cranes.
Marine crane vs offshore crane at a glance
The two terms overlap, which is why buyers mix them up. The table sets out the practical differences that decide which crane fits a job.
| Point | Marine crane (general) | Offshore crane |
|---|---|---|
| Where it is installed | Ship or workboat deck, barge, pontoon, quay or jetty | Fixed platform, jack-up, floating production unit, semi-submersible or offshore vessel |
| Typical lifts | Cargo, stores, equipment and small boats in port or sheltered water | Containers, pipe and equipment to and from supply vessels; internal platform lifts |
| Water conditions | Calm to moderate water, usually alongside a quay or at anchor | Open sea, with the supply vessel rising and falling under the hook |
| Load chart | Rated load against working radius | Rated load against radius and significant wave height |
| Design standard | Maker’s design; class rules if the owner asks for classing | API Spec 2C, EN 13852-1 or a class offshore standard |
| Certification | Depends on the vessel, flag and owner | Normally third-party certified and required by the operator or regulator |
| Lifting people | Not intended, unless separately designed and approved | Covered by the offshore standard when the crane is built for it |
What is a marine crane?
A marine crane is a crane designed to work on or beside water, where salt air, spray and the motion of a hull affect its operation. Most are hydraulic slewing cranes on a pedestal, with a knuckle boom or a telescopic boom. Our marine crane range is typical of the class: compact, hydraulically driven and bolted to a deck or a concrete base.
Lloyd’s Register’s Code for Lifting Appliances in a Marine Environment shows how wide the family is. It covers cranes on ships for cargo, equipment and personnel, cranes on barges and pontoons, and cranes on fixed or mobile offshore installations. In everyday trade the word “marine crane” usually means the first two groups. These are the main ones:
- Deck and ship cranes load cargo and stores on cargo vessels, landing craft and supply boats. See our deck crane guide.
- Boat cranes handle nets, catch, tenders and gear on fishing boats and workboats. See the boat crane guide.
- Barge and pontoon cranes turn a flat hull into a floating work platform. See the barge crane guide and our floating crane guide.
- Quay and pedestal cranes stand on a jetty or plinth and serve boats alongside. See the pedestal crane guide.
What these cranes share is sheltered or moderate water. The boat is usually alongside a quay or at anchor, and the operator chooses when to lift. For how the hydraulics work, read our ship crane working principle guide, and for the parts, the marine crane parts guide.
What is an offshore crane?
An offshore crane is a slewing crane mounted on an offshore installation or vessel, whose duties include handling loads to and from supply vessels, barges or semi-submersibles in open sea. That is how Cranes Today describes the scope of the European offshore crane standard in its article How to build an offshore crane [1].
The current draft of that standard, prEN 13852-1, applies to general-purpose offshore cranes with steel structures, including their pedestals. It covers the lifting of goods and of persons [2]. Several kinds of crane sit outside Part 1 and have their own rules:
- General-purpose offshore cranes: pedestal cranes on platforms and production units that serve supply vessels. These are what most people mean by “offshore crane”.
- Light offshore cranes: smaller cranes on offshore installations, covered by EN 13852-3.
- Floating cranes: cranes on a vessel or barge built for construction work at sea, covered by EN 13852-2.
- Motion-compensated and subsea cranes: cranes that lower loads through the water to the seabed. These are excluded from Part 1 and engineered lift by lift.
At the very top end are crane vessels. Wikipedia notes that the largest crane vessels are used for offshore construction, often on semi-submersible or catamaran hulls for stability [3].
Six differences that matter
1. Where they work and what they lift from
A marine crane mostly lifts from its own deck, from a quay or from a boat that is tied alongside. An offshore crane regularly lifts from another floating object. Cranes Today lists the lift types used in offshore crane design: internal lifts, platform lifts, supply boat lifts, lifts in air, submerged lifts and seabed lifts [1].
Of these, the supply boat lift is the hardest. At lift-off the hoist, the crane tip and the boat deck are all moving, so the relative speed between hook and load is highest. A lift from the crane’s own deck is the closest to a lift on land.
2. Sea state and dynamic loads
Waves are the root of nearly every other difference. Significant wave height is the usual measure of sea conditions. As Wikipedia’s article on significant wave height explains, it is traditionally the mean trough-to-crest height of the highest third of the waves [4]. The WMO sea state code turns that into ten bands, from calm to phenomenal.
Offshore crane loads are shaped by that motion. Cranes Today’s Dynamic decisions puts the average wave height when unloading vessels in the North Sea at around 3 m. A hoist timed as the vessel drops into a trough can raise the load on the crane to as much as three times the lifted weight [5].
By contrast, a harbour crane rarely sees that. Its boat is moored, the water is far calmer, and the operator can wait for the hull to settle. This is the main reason a marine crane built for sheltered water should not be sent offshore.
3. How the load chart is written
A standard marine crane load chart gives the rated load at each working radius. Our charts work this way, and our guide on how to read a crane load chart explains them.
However, an offshore crane adds a second dimension. According to Cranes Today, offshore load charts are normally tied to significant wave height rather than wind speed. The higher the waves, the lower the safe working load, so the same crane is rated for less on a rough day [1]. The design calculates a dynamic factor for each sea state and lift type, from the hoisting speed, the crane tip speed, the boat’s speed and the crane’s stiffness.
4. Design standards
Offshore cranes are built to offshore standards. In the United States that means API Spec 2C for offshore pedestal-mounted cranes, with API RP 2D for operation and maintenance. In Europe it means EN 13852-1, and class societies publish their own offshore crane standards.
In practice, these standards ask for more than a stronger boom. Cranes Today notes stricter Charpy V-notch impact requirements for the steel, because offshore loads are less predictable and lifts happen at low temperatures. It also notes higher wire rope safety factors to allow for dynamic loading [1]. A general marine crane is designed to its maker’s rules and, only when the owner asks, to a class society’s code for shipboard lifting appliances.
5. Safety systems
Every hydraulic crane needs overload protection and emergency stops. The offshore standard goes further. The prEN 13852-1 summary lists these safeguarding systems [2]:
- Rated capacity indicator and rated capacity limiter
- Automatic overload protection system (AOPS)
- Manual overload protection system (MOPS)
- Emergency load lowering, emergency stop, and wind and hoist indicators
- Motion detection, dropped object protection and fire prevention
These systems answer the risks of lifting from a vessel that is moving in open sea. A crane serving a moored boat in a harbour is designed around calmer, more predictable lifts, so its safety equipment is specified for that duty instead.
6. Certification, records and operation
Offshore cranes sit inside a tighter legal frame. On the US outer continental shelf, 30 CFR 250.108 sets these rules for cranes on fixed platforms [6]:
- They must be operated in line with API RP 2D.
- They must have a functional anti-two-block device.
- Cranes on platforms installed after 17 March 2003, and cranes made after that date, must meet API Spec 2C.
- Design and construction records are kept on the platform for the life of the crane.
- Inspection, testing and maintenance records, and the qualification records of operators and riggers, are kept for at least 4 years.
In addition, other offshore regions have their own regulators and rules. The pattern is the same: the operator or regulator demands a certified offshore crane, and the buyer cannot simply choose a cheaper alternative.
Can a marine crane be used offshore?
Not as a substitute for an offshore crane. Some jobs involve lifts from supply vessels in open sea. Others come with a requirement for API Spec 2C, EN 13852-1 or class offshore certification. Either way, you need a crane designed and certified for that duty. A standard marine crane was not designed for the dynamic factors, wave-height load charts or overload protection described above.
On the other hand, the reverse is common and sensible. Many lifting jobs at sea are not offshore jobs at all. A crane that loads a supply boat in port, moves cargo on an island ferry or handles gear on a workboat in a sheltered bay does marine work. A well-sized marine crane does that work at a fraction of the size and complexity of an offshore crane.
Which one do you need?
Answer these questions before you ask for quotations. If you answer “yes” to any of the first three, talk to a supplier of certified offshore cranes.
- Will the crane lift to or from another vessel in open sea, away from a quay?
- Will it be installed on a fixed platform, jack-up, production unit or semi-submersible?
- Does your client, flag state or regulator require API Spec 2C, EN 13852 or class offshore certification?
- Will the crane work in a harbour, river, lake, lagoon or other sheltered water? A marine crane fits.
- Is the crane mainly for cargo, stores, nets, tenders or equipment on your own vessel or quay? A marine crane fits.
Example scenario (an illustration, not a customer record): an island cargo operator runs a landing craft between a main port and outer islands inside a reef lagoon. It needs to lift pallets of cement and fuel drums of up to 1 t at about 7 m from the centre of the crane. The work is in sheltered water, alongside simple jetties, with no platform or regulator requiring offshore certification. A marine knuckle boom crane with that reach is the right tool. If the same company won a contract to supply a gas platform in open water, that contract would call for a certified offshore crane on the platform and a different conversation.
What BOB-LIFT makes: marine cranes for sheltered water
Our knuckle boom marine cranes and telescopic boom marine cranes run from 0.8 t to 25 t. The T in a model name marks the marine version. They have no class-society certification and are not offshore cranes. The table shows seven models, with figures from each crane’s current technical drawing.
| Model | Boom | Max capacity | Max working radius / load there | Recommended power | Crane weight |
|---|---|---|---|---|---|
| SQ2ZA2TJ | Knuckle, winch | 2,000 kg | 5.1 m / 750 kg | 9 kW | 590 kg |
| SQ5ZA3TJ | Knuckle, winch | 5,000 kg | 8.05 m / 1,100 kg | 22 kW | 2,120 kg |
| SQ10ZA6TJ | Knuckle, winch | 10,000 kg | 14.68 m / 1,150 kg | 30 kW | 2,920 kg |
| SQZ500T | Knuckle | 25,000 kg | 18.0 m / 2,000 kg | 55 kW | 6,474 kg |
| SQ5SA4T | Telescopic | 5,000 kg | 11.79 m / 600 kg | 18 kW | 2,100 kg |
| SQ12SA4T | Telescopic | 12,000 kg | 16.19 m / 1,200 kg | 45 kW | 4,050 kg |
| SQ20SA5T | Telescopic | 20,000 kg | 22.0 m / 1,500 kg | 55 kW | 6,950 kg |
The recommended power is what the crane’s hydraulic power unit needs. It comes from an electric or diesel power pack, so check your vessel’s spare electrical capacity early. Remember that capacity falls quickly with radius, so choose by the load you need at the reach you need, not by the headline tonnage. Our knuckle boom vs telescopic marine crane comparison and marine crane buying guide go through the other choices.
Frequently asked questions
Is an offshore crane a type of marine crane?
Yes. Every offshore crane works in a marine environment, so it belongs to the broad marine crane family. It is the specialised member designed and certified for open-sea lifts on platforms and between installations and supply vessels.
What standard applies to offshore cranes?
The common ones are API Spec 2C for offshore pedestal-mounted cranes and EN 13852-1 for general-purpose offshore cranes in Europe. API RP 2D covers operation and maintenance, and class societies publish their own offshore crane standards. Your operator or regulator decides which one applies.
Why are offshore cranes rated by wave height?
Because the supply vessel moves up and down under the hook. Higher waves mean faster relative motion at lift-off and larger dynamic loads, so the safe working load is reduced as the significant wave height rises.
What is the difference between a deck crane and an offshore crane?
A deck crane serves its own ship’s cargo and stores, usually in port or sheltered water. An offshore crane serves an offshore installation and lifts from supply vessels in open sea, to an offshore standard with wave-height load charts.
Are BOB-LIFT marine cranes certified for offshore use?
No. Our marine cranes have no class-society certification and are not offshore cranes. They are made for workboats, cargo vessels, barges, pontoons and quays in harbours, rivers and sheltered coastal water. We supply the crane only, not the vessel.
How we compiled this guide
We rewrote this guide in November 2026 to replace an older, shorter version. The offshore crane scope and safety systems come from the iTeh summary of prEN 13852-1. Load charts, lift types, dynamic factors and steel requirements come from the Cranes Today articles “How to build an offshore crane” and “Dynamic decisions”. The US rules are from the official eCFR text of 30 CFR 250.108. The scope of marine lifting appliances is from Lloyd’s Register’s code page, and the wave definitions are from the Wikipedia articles “Significant wave height”, “Sea state” and “Crane vessel”. All were read in November 2026. Every figure in the BOB-LIFT table comes from the current technical drawing of that model, and the quay photo was sent by a customer in the Maldives. Achord Chan, Product Operations Director, reviewed the guide. It does not replace the standard your project requires, your crane manual or the law where you work.
Tell us where your crane will work
Send us your heaviest load, the reach you need, your vessel or quay and the water it works in. If the job is in sheltered water, we will recommend a marine crane with its technical drawing and load chart. If it needs a certified offshore crane, we will tell you plainly. Every crane carries a 12-month warranty on the whole machine, common spare parts leave the factory within 48 hours, and our service team answers within 12 hours. Contact us for a quotation.
