Harbor Crane Selection: Portal vs Gantry vs Bridge
Key Takeaway Selecting the right crane for a port terminal comes down to three application zones: ship unloading at the quayside calls for a portal crane (16–80 t capacity / 20–45 m working radius / 360° slewing / $220,000–$890,000), yard storage requires a gantry crane (40–100 t capacity / 25–50 m span / cantilever options / $120,000–$520,000), and maintenance shops or general cargo warehouses are best served by an overhead crane (10–160 t / $30,000–$300,000). A typical integrated setup pairs a portal crane for unloading, AGVs for horizontal transport, a gantry crane for yard stacking, and an overhead crane for in-warehouse handling. All equipment must meet IP55 outdoor protection for port environments and be fitted with rail clamps for wind safety.
Kelude Heavy Industry has spent years specializing in port lifting equipment, and ports are among the most crane-dense environments in the world—from ship unloading to yard stacking to warehouse distribution, every stage demands the right machinery. Yet one of the most common mistakes port operators make is deploying the wrong crane type at the quayside, or creating a bottleneck where yard and workshop capacities don't align. This article breaks down the selection essentials for the three main crane types—portal cranes (quayside), gantry cranes (yard), and overhead cranes (maintenance/warehouse)—and presents a full-process configuration solution for port terminals.
Portal Cranes: The Workhorse for Quayside Unloading
Portal cranes are the standard ship-unloading equipment at port quaysides. Their portal base leaves a clearance of at least 6 m for trucks and railcars to pass underneath, while the boom slews a full 360° to cover both the vessel's holds and the apron. They come in two configurations: bulk cargo portal cranes (fitted with a grab bucket, 16–40 t capacity) and general cargo portal cranes (fitted with a hook, 25–80 t capacity).
Selection Parameters: Lifting capacity is determined by the heaviest single load × 1.2 (including the lifting spreader). Working radius (maximum outreach) is dictated by vessel size—a 30,000 DWT bulk carrier requires a radius of at least 25 m, 50,000 DWT requires 30 m, and 100,000 DWT requires 35 m. Lifting speed for bulk grab operations is typically 8–12 m/min (heavy load), while general cargo runs at 6–10 m/min. Work duty classification ranges from A6 to A7 (port terminals typically operate 18–24 hours per day). Portal cranes are a mature technology supplied by specialized port crane manufacturers; Kelude offers full-machine retrofits and electrical system upgrades.
Retrofitting Aging Port Cranes: Many older port portal cranes have been in service for 15–20 years and suffer from low efficiency and high failure rates. Upgrading the electrical system (replacing cam controllers with variable-frequency drives plus PLC) is the most cost-effective retrofit solution—lifting efficiency improves by roughly 20% and failure rates drop by more than 50% after the upgrade. For more technical details on portal crane VFD retrofits, refer to Non-Standard VFD Retrofit Solutions for Harbor Portal Cranes.
Gantry Cranes: The Core of Yard Storage Operations
Port yards fall into two categories—container yards and bulk/general cargo yards—and gantry cranes are the equipment of choice for both. They are classified by travel mode: rail-mounted gantry cranes (RMG) and rubber-tyred gantry cranes (RTG).
Container Yards: Yard width is typically designed for 8–12 rows of containers plus 1–2 truck lanes, requiring a gantry span of 25–40 m and a lifting capacity of 40–65 t (standard container weight of 30 t plus spreader dead weight). RMGs offer a higher degree of automation (can be integrated with automatic stacking systems), while RTGs provide greater flexibility with the ability to move between yard blocks. RTGs are powered by a diesel generator with electric drive (hybrid) or pure electric drive (lithium battery with conductor rail charging); the all-electric option cuts energy costs per TEU by 60% compared to diesel.
Bulk and General Cargo Yards: For storage of steel, timber, mineral powders, grain, and similar materials, MH-type or MG-type gantry cranes are the standard choice, with lifting capacities of 16–50 t and spans of 22–40 m. Configuration essentials: given the outdoor, coastal high-salt environment, the corrosion protection level must reach C4–C5 (hot-dip galvanized bolts + epoxy zinc-rich primer + polyurethane topcoat with a minimum total thickness of 280 μm). Electrical systems and motors must be rated IP55. Rail clamps, rail wedges, and anchor devices are mandatory, verified against wind load requirements per ISO 4301.
Overhead Cranes: For Maintenance Shops and General Cargo Warehouses
Port maintenance shops handle the inspection and repair of portal cranes, gantry cranes, and mobile machinery, requiring hoisting coverage throughout the entire disassembly and repair process. Lifting capacity is determined by the heaviest component being serviced (such as a portal crane slewing ring, a complete diesel engine, or a gantry crane trolley frame), typically ranging from 20 to 80 t. Workshop spans generally fall between 22 and 31 m, with a work duty classification of A5. Configuration essentials: double hook (main hook for lifting major assemblies, auxiliary hook for smaller parts), variable-frequency speed control with both radio remote and cabin operation, and an enclosed cabin with industrial air conditioning.
General cargo warehouses store goods that cannot be left outdoors (such as pulp, non-ferrous metals, and machinery). These facilities are equipped with LD-type or LH-type overhead cranes with lifting capacities of 5–20 t, spans of 18–30 m, and work duty classifications from A4 to A5. Overhead cranes in warehouses are typically operated via wireless radio remote control, eliminating the need for a cabin. When multiple cranes operate on the same runway, anti-collision devices are required.
Full-Process Configuration and Investment Comparison
| Operation Stage | Equipment Type | Lifting Capacity | key parameters | special requirements | Reference Price(10,000 CNY) |
|---|---|---|---|---|---|
| Ship Unloading | Portal crane | 16~80t | Working radius20~45m/Track Gauge / Rail Gauge10.5~16m | IP55/Rail clamp/Corrosion Resistant C4 | 150~600 |
| Stockpiling | Gantry Crane | 40~100t | Span25~50m/With Cantilever | RMG/RTG/Rail clamp/anchoring | 80~350 |
| In-Warehouse | Bridge Crane / Overhead Crane | 5~20t | Span18~30m | Remote control operation/anti-collision | 15~60 |
| Maintenance | Bridge Crane / Overhead Crane | 20~80t | Span22~31m/Double Hook | Closed-Type Cabin / Operator Cab/Variable Frequency Drive (VFD)+remote control | 30~150 |
Port Terminal Crane Data: Key Specs at a Glance
Frequently Asked Questions
Q: Which is more efficient for vessel unloading: a harbor portal crane or a gantry crane?
A: Portal cranes and gantry cranes serve different roles—they complement rather than replace each other. A portal crane works directly at the quayside, with a slewing boom that reaches into the vessel's hold, achieving 40–60 lifts per hour (with grab bucket for bulk cargo). A gantry crane mounted on the quayside (i.e., a quay crane or container bridge crane) offers higher throughput at 30–40 containers per hour, but is limited to container ships. For general and bulk cargo terminals, the standard approach remains a portal crane for unloading paired with a gantry crane for yard storage—a combination that supports terminal throughput of 3–5 million tons per year.
Q: What corrosion protection level is required for outdoor port cranes?
A: Ports sit in coastal, high-salinity environments, so the corrosion protection level must meet C5 (ISO 12944). The coating system should be: Inorganic Zinc Silicate Primer 80μm + Epoxy MIO Intermediate Coat 80μm + Polyurethane Topcoat 80μm (total dry film thickness ≥240μm). Bolts and connectors should be hot-dip galvanized (zinc layer ≥85μm). Electrical cabinets should be rated IP55 (IP56 recommended for coastal areas). Inspect and touch up the coating annually. With proper anti-corrosion treatment, the typical service life of a port crane is 15–20 years, extendable to 25+ years.
Q: What is the return on investment for a VFD retrofit on a portal crane?
A: Legacy portal cranes using cam controllers with rotor series resistance speed control are energy-intensive and costly to maintain. A VFD retrofit (AC-DC-AC inverter + PLC + dynamic braking) costs approximately $44,500–$118,600 per unit (depending on tonnage), delivers 20–35% energy savings, and cuts electricity costs by about $7,400–$22,200 per year. The retrofit also reduces mechanical shock by roughly 60%, extending gearbox and brake service life by 2–3 years. Typical payback period: 2–4 years. Beyond energy savings, the VFD retrofit increases lifting speed by about 15–20%, directly boosting terminal throughput.
Q: What special requirements apply to overhead cranes in port maintenance workshops?
A: Overhead cranes for maintenance workshops have specific requirements: ① A dual hook configuration is essential—the main hook handles large components (e.g., a 30t slewing platform for a portal crane), while the auxiliary hook handles smaller parts (brakes, couplings, etc.); ② Lifting height must clear the tallest equipment in the workshop (e.g., a portal crane boom in the vertical position stands about 15m tall); ③ A closed air-conditioned cabin is required (temperatures inside shipyard and terminal maintenance shops can reach 45°C in summer); ④ Since welding and gas cutting may occur simultaneously in the workshop, cabin windows must have sun/glare shields. Kelude has supplied QD-type dual-hook overhead cranes with VFD control to multiple port maintenance facilities.
