A wind component carrier is not a scaled-up container carrier. Nacelles concentrate mass into a short, offset envelope, tower sections are long and thin with stiff flanges at each end, and blades are flexible structures with a published limit on how far they may bend. Each family needs its own attachment and its own load case, and a yard that handles all three usually needs either a convertible machine or two.
Wind farm construction has moved a large share of its lifting work from the erection crane to the laydown yard. Components arrive by road, rail or vessel, sit in storage for weeks or months, and are then fed to the crane in a fixed sequence. Every one of those moves happens at ground level, at walking pace, with a load that is worth more than the machine carrying it.
That is the duty a straddle carrier suits. It travels on its own wheels, it can straddle a stored component instead of approaching from the end, and it puts the load between the legs where the operator can see both sides. This page covers what changes when the load is a turbine rather than a container: the component families, the lift points, blade limits, the machine configuration, the yard, and what to send with an enquiry.
Why wind components are a different duty
Four properties separate turbine handling from container or steel work.
- Fixed lift points. The OEM defines where the component may be lifted, and often how. A spreader that bears anywhere else is not a cheaper solution; it is an unapproved lift. The machine has to reach the points the component offers, which is why portal width and lift height are driven by geometry rather than by weight.
- Concentrated or offset mass. A nacelle packs a drivetrain, a generator and a yaw system into a short body, and the centre of gravity is rarely in the middle. Tower sections are the opposite: mass spread along a thin shell, with most of the stiffness at the flanges.
- Flexibility with a limit. A blade is a structural spring. It bends under its own weight when lifted at two points, and the manufacturer publishes how much bending and which sling angles are acceptable. Exceeding it does not usually break the blade on site; it produces a defect that is found later.
- Value and surface. These are finished, coated, often certified components. Contact damage, gel-coat cracking and leading-edge marks are warranty issues. Protection is part of the attachment, not an accessory added afterwards.
Duty class matters as much as the load. A port that tranships turbine components may make a few hundred lifts a year; a manufacturing yard feeding a production line may make that in a month. The two belong in different classification bands even when the components are identical.
The component families
The ranges below are for utility-scale platforms and vary by OEM, by generation and between onshore and offshore designs. Treat them as context, not as a specification: the numbers that matter are the ones on your component drawings.
| Component | Typical form | What it changes |
|---|---|---|
| Nacelle | Short, heavy, box-like body with an offset centre of gravity and defined lifting points on the frame or the housing. | Rated capacity at a short load centre, a spreader that matches the lift points, and headroom for the housing height. |
| Tower section | Long steel shell, tapered, with a machined flange at each end and lifting lugs or trunnions near the top flange. | Portal length, lift height, a long-load stability case, and a route that lets the machine travel with the section along the aisle. |
| Blade | Long, tapered, flexible composite shell, lifted at the root and at a marked point along the span. | A blade yoke or clamp, a controlled bending allowance, and the largest swept envelope in the yard. |
| Hub, drivetrain, base frame | Compact cast or fabricated assemblies, often with an irregular outline and no convenient lifting face. | Purpose-made slinging or a trunnion adapter, plus a stability check for an asymmetric load. |
A yard that stores all four families will usually need more than one attachment, and possibly more than one machine. It is cheaper to decide that at the specification stage than to discover it during the first campaign.
The load cases that decide the machine
Capacity on a nameplate tells you very little about a turbine carrier. Six load cases do the real work.
- Rated capacity at the real load centre. A nacelle's centre of gravity may sit a metre or more from the geometric centre, and a short load centre is not a generous one. Always compare capacity curves at the actual centre, not at the maximum radius.
- Long-load bending. A tower section carried at two points behaves as a beam. The carrier's suspension, the travel speed and the ground profile all feed into the bending case, and the section's own stiffness may be lower than the frame that carries it.
- Blade bending and root moment. The blade is the only common wind load where the permitted deflection, not the mass, usually governs the attachment design.
- Wind sail area. A blade or a tower section presents a large surface to the wind. A component that is stable in still air can be unmanageable in a gust, which is why operational wind limits belong in the machine's operating procedure.
- Wheel loads on the storage surface. Laydown yards are often compacted gravel, temporary hardstanding or a quay slab with a published load limit. The loaded wheel load per corner, unladen and laden, is the number the yard designer needs.
- Transport interface. The handover from trailer, SPMT or vessel to the carrier is where most of the cycle time and most of the risk sit.
Attachments for turbine components
The attachment is decided before the machine, because it sets the load case.
| Attachment | Used for | What to watch |
|---|---|---|
| Multi-point lifting beam | Nacelles and other components with two or four defined lifting points. | The beam has to match the point spacing exactly; sling angles change both the load in the component and the headroom. |
| Blade yoke or clamp | Blades, gripped at the root and supported along the span. | Contact pressure on the shell, the permitted sling angle, and the bending allowance published by the blade maker. |
| Trunnion or lug adapter | Tower sections lifted from the top flange lugs or from trunnions. | Whether the section hangs vertically or travels horizontally, and how the adapter is locked against rotation. |
| Slings and soft slings | Irregular assemblies and one-off loads. | Manual work per lift, edge protection, and a sling plan that is written down rather than agreed on the day. |
A rotating or slewing head is common on turbine carriers, not to spin the load for its own sake but to align a component with a storage row or a trailer without repositioning the whole machine. That adds a load case and a stability check; it is a structural decision.
Blades: the flexible load
Blades are the component that most often forces a different answer. A blade is designed to bend, and it does so under its own weight as soon as it is lifted at two points. The manufacturer usually publishes a maximum tip deflection and a permitted sling configuration; working outside either is a quality risk that appears months later as a structural defect.
- Two-point lifting is normal. Root and a marked span position. The yoke or clamp at each point has to hold the section without crushing the shell, which means a defined contact area and a controlled clamping force.
- Bending is managed, not eliminated. The attachment geometry and the sling angle are chosen so the blade bends within its allowance. A shorter sling is not automatically safer.
- Storage drives the yard. Blades are stored in racks, often at height, and the carrier has to reach the rack without the blade tip sweeping into the next row. The swept envelope, not the blade length, is the planning dimension.
- Wind is a hard limit. A blade is a sail. Operating limits are usually set by the OEM and by the yard's procedure, and they are lower than for a comparable steel load.
Machine configuration
With the components and attachments settled, the machine is a set of clearances and weights.
- Portal inside width is set by the widest component plus its attachment plus operating clearance — and where the machine must straddle a storage row, by the row.
- Clear lift height follows the highest rack or stack the yard will build, plus the attachment depth. Blade racks are usually the tallest thing in the yard.
- Portal length matters more than in container work: a long tower section carried between the legs needs a wheelbase and a frame that can take the bending case without imposing it on the load.
- Rated capacity is quoted at a load centre. For a nacelle the centre is short and the mass is high; for a blade the mass is low but the moment is large. Both cases must be checked on the same chart.
- Wheel arrangement and steering follow the yard. Crab and four-wheel steering reduce the swept path where aisles were laid out for trailers rather than portals.
- Drive follows the location: diesel for gravel laydown yards and long routes, electric or hybrid where the machine works inside a production hall or under a strict emissions rule.
Published models cover the smaller end of this duty directly. Above that, and for any component with unusual geometry, the machine is designed around the component — the selection guide sets out the order in which those numbers should be fixed, and the specifications page shows what can be quoted without a project-specific design.
Laydown yard, port and route
Turbine storage is usually the tightest constraint in the project, because the yard is temporary, the ground is often not designed for the wheel loads, and the storage plan changes with every campaign.
- Aisle width along the loaded route, including corners, and including the sweep of a blade tip or the overhang of a tower section.
- Storage geometry: row pitch, rack height, and whether components are stored on timber, steel cradles or bespoke saddles.
- Transport interface: trailer deck height, SPMT platform, rail wagon or quay edge — each has a different approach angle and a different clearance.
- Ground: bearing capacity, slope, drainage and any area where the surface is thinner than the rest. Temporary yards change with the weather.
- Overhead: lighting masts, power lines, crane booms parked in the storage area.
Two measurements catch people out. The first is the turning envelope with a long component carried off-centre: the machine may fit the aisle while the load does not. The second is the gap between storage rows, because a carrier needs clearance on both sides at once — a bay that worked for a telehandler is often too tight for a portal.
Safety, weather and control
- Operating wind limits per component, written into the procedure rather than left to judgement. A blade and a nacelle do not share a limit.
- Load monitoring visible to the operator: overload protection, hoist limits, and where fitted, anti-sway.
- Exclusion zones during lifting, sized to the swept envelope rather than to the machine footprint.
- Lift-point discipline: only the points the OEM defines, with the correct pins, shackles and torque values, recorded per lift where the contract requires it.
- Damaged components segregated, because a blade with a leading-edge repair or a tower section with a dented shell behaves differently under load and belongs in quarantine.
Standards and documentation
Turbine carriers are designed and documented against the same crane standards as other lifting machines. The relevant ones for this duty are:
- ISO 4301-1 and ISO 4301-5 — classification of the machine by duty.
- EN 15011 — bridge and gantry cranes, which covers the structural approach for portal machines.
- EN 13001 — general design of cranes, used for the proof-of-competence route.
- IEC 60204-32 — electrical equipment of hoisting machines.
- ISO 12488-1 — tolerances for wheels and travel tracks.
Standards are cited by number here; the edition that applies to a given contract is confirmed with the drawing package. Component-specific requirements come from the OEM and sit above the general standard — a blade maker's sling plan overrides anything in this page. Ask for the classification, the load chart at the real load centres, and the wheel-load calculation as a set; they should agree with each other.
What to send with an enquiry
Six items are enough for a first configuration.
- The component list: nacelle, tower sections, blades, hubs — with mass and overall dimensions for each.
- The lifting points, as drawings or OEM documents, including any sling-angle restriction.
- Storage method and maximum rack or stack height.
- A yard plan with storage rows, aisles, the transport interface and overhead obstructions.
- Ground information: surface, bearing capacity if known, slope and drainage.
- Throughput and campaign pattern, so duty class and drive can be set against the real workload.
Send them as drawings, photographs or a spreadsheet. The review usually identifies one or two numbers that decide the machine, and they are rarely the ones on the enquiry form.
Wind energy FAQ
Can one carrier handle nacelles, towers and blades?
Sometimes, with a convertible attachment set and enough headroom. More often the blade drives the yard geometry and the nacelle drives the capacity, and the two pull in different directions. A single machine is a legitimate answer when the campaign is small or when the same yard will not store all three at once.
How is blade bending controlled during transport?
By the attachment geometry and the sling angle, working within the blade maker's published allowance. The carrier does not stiffen the blade; it holds it at the defined points and lets it deflect as designed. Any change to the sling plan has to be agreed with the blade manufacturer.
What ground bearing does a loaded carrier need?
It depends on the loaded wheel loads, which depend on the component, the attachment and the machine. We return wheel loads per configuration — laden and unladen — so your yard designer can check the hardstanding against the real machine rather than an estimate.
Can the machine work on a quay or inside a production hall?
Yes, with the right drive and the right wheel loads. Quay slabs have published limits, and indoor work usually means electric or hybrid drive, a floor loading check and a charging strategy that fits the shift pattern.
What wind speed stops a lift?
The limit is set per component by the OEM and by the site procedure, and it is lower for blades than for steel. We provide the machine's own operating envelope; the component limits come from the manufacturer and the yard's safety case.
Do you supply the lifting attachments?
Yes, as part of the machine package, designed around the component lift points you supply. Where an OEM already owns a yoke or a beam, the machine can be built to interface with it instead.