How to Choose a Marine Crane for Hatch Covers & Winches
Marine ancillary equipment—hatch covers (1–5 t/pc), windlasses (3–8 t/unit), winches (2–6 t/unit), and steering gears (1–3 t/unit)—consists of large steel structures and precision drive components. A QD double-girder crane (10–20 t) with an electromagnetic suction cup, paired with an LD single-girder crane (5–10 t) and a KBK system (2–3 t), is the recommended configuration. Kelude’s marine ancillary solution covers all four core component types.
Hatch Cover Welding & Hoisting: Large Steel Plate Splicing and Flipping
Hatch covers are welded steel or aluminum structural components, with maximum dimensions of 6m × 8m and individual weights ranging from 1 to 5 tons. The process involves plate splicing, welding, flipping, and back-side welding. Flatness requirements for hatch covers are ≤ L/1000 (e.g., a 6m-long hatch cover must have flatness ≤ 6mm). Welding deformation control is critical.
Recommended Model: QD-type double-girder bridge crane, 10–20t capacity with an 18–24m span, equipped with a lifting magnet (3–5t lifting force) for rapid steel plate handling, paired with a flipping welding positioner (5t capacity, 1 rpm rotation speed) for double-sided welding. A welding fume extractor (capacity ≥ 2,000 m³/h) is recommended for the welding area.
Price Reference: QD double-girder 10t/20m: approximately $18,000–$30,000 per unit; lifting magnet: approximately $1,500–$3,000 per set. Kelude's hatch cover solution comes standard with remote-controlled lifting magnets and overload protection.
Windlass Assembly: Chain Wheel, Base, and Drive Alignment
The windlass consists of a chain wheel (cast steel, 1–3t), a base (welded steel plate, 1–2t), and a motor/gearbox assembly (1–3t). The chain wheel's sprocket grooves require high machining accuracy (pitch error ≤ 0.5mm). Assembly involves flipping and bolt tightening (M30–M48 bolts).
Recommended Model: QD-type double-girder bridge crane, 10t capacity, covering the assembly line. A C-hook spreader is used to lift the chain wheel and position it onto the base for tack-up. A dedicated 3–5t jib crane is installed above the test bench (equipped with a hydraulic torque wrench rated up to 8,000 Nm) for accessory installation and removal.
Price Reference: QD double-girder 10t/18m: approximately $15,000–$27,000 per unit; hydraulic torque wrench: approximately $4,500–$7,500 per set. Kelude's windlass solution integrates test bench lifting with torque wrench operation.
Winch Drum Machining: Turning and Welding Operations
Winch drums range from 1 to 3 meters in diameter and consist of a drum body (rolled and welded steel plate, 1–3t), end plates (cast steel, 500–1,000 kg), and a shaft (forged steel, 300–800 kg). The drum's outer surface requires machining on a large horizontal lathe (diameter accuracy to IT8 grade), with a welding roller stand assisting in the welding area.
Recommended Model: LD-type single-girder electric crane, 5–10t capacity with a 12–18m span, equipped with a V-type support frame (120° opening angle) for drum loading and unloading. The welding area is fitted with a welding roller bed (5t capacity, adjustable speed 0.1–1 rpm), while the crane handles tack-up and transport.
Price Reference: LD single-girder 5t/15m: approximately $7,500–$15,000 per unit; roller bed: approximately $1,500–$3,000 per set. Kelude's winch solution includes a double-hook spreader for level drum lifting, preventing tilting.
Precision Steering Gear Assembly: Gearbox Alignment and Testing
Steering gears are precision hydraulic or electric drive units with gearboxes weighing 1–3t. Internal gear alignment tolerance is ≤ 0.05mm. Assembly requires a clean environment (dust-free assembly room), and precise positioning demands millimeter-level micro-motion capability. Seal integrity testing is conducted at pressures of 20–30 MPa.
Recommended Model: KBK flexible modular crane, 2–3t capacity, fitted with a variable-frequency drive (VFD) electric hoist (slow speed ≤ 0.5 m/min) for precision gearbox alignment. A hydrostatic load test bench (max torque 10,000 Nm) is installed in the assembly area, with a jib crane overhead for auxiliary disassembly and assembly.
Price Reference: KBK system 2t: approximately $6,000–$12,000 per set; VFD electric hoist adds approximately 20% to the cost. Kelude's steering gear solution includes micro-motion functionality and a positive pressure ventilation system for the clean assembly room.
Marine Ancillary Equipment Lifting Configuration Comparison
| Component | recommended model | tonnage | special requirements | reference price |
|---|---|---|---|---|
| hatch cover | QDDouble Girder+Lifting magnet | 10~20t | Tiltingwelding positioner | 12~20Universal |
| windlass | QDDouble Girder+C-hook spreader | 10t | Hydraulictorque wrench | 10~18Universal |
| winch | LDsingle girder+roller bed | 5~10t | VType Support/Double Hook | 5~10Universal |
| steering gear | KBK+Variable Frequency Drive (VFD)Electric Hoist | 2~3t | Micro-motion≤0.5m/min | 4~8Universal |
Key Parameters for Marine Ancillary Equipment
Kelude Crane Solutions for Marine Equipment: Service Advantages
Kelude Heavy Industry has years of experience serving the marine ancillary equipment sector. With a 50,000 m² production facility and ISO 9001 Quality Management System certification, we deliver differentiated crane solutions for four key customer segments: hatch covers, windlasses, winches, and steering gear.
Heavy Lifting Plans
Our core offering combines QD double-girder cranes with lifting magnets and hydraulic torque wrenches, covering the full assembly process for hatch covers, windlasses, winches, and steering gear.
Customized Protection
Standard three-layer protection using nylon slings, silicone protective sleeves, and specialized spreaders prevents surface damage and deformation during assembly.
Whole-Line Layout Planning
We provide complete layout plans for marine equipment workshops—covering crane type, tonnage, rail routing, and workstation density at each position—ensuring zero interference between equipment and maximum operational efficiency.
Frequently Asked Questions
Q: How can welding distortion in hatch covers be controlled with crane assistance?
A: Distortion control for hatch cover steel plate splicing welds: ① Pre-deformation method—set a pre-deformation angle (2–3°/m) on the platform before welding; the plate springs back after welding. ② Forced restraint—use lifting magnets to hold the plate flat against the platform during welding. ③ Symmetrical welding—two welders work simultaneously from the center toward both ends. Kelude Heavy Industry's lifting magnets (with adjustable holding force from 0 to 100%) are well suited for the pre-deformation method.
Q: What lifting capacity is required for a windlass test bench?
A: Windlass testing includes no-load and load tests (rated pulling force 500 kN), during which the anchor chain sprocket rotates. Lifting requirements around the test bench: ① Motor/gearbox erection and dismantling—a dedicated jib crane rated 3–5 t with a 3 m slewing radius; ② Test fixture handling—fixtures weighing 200–500 kg need light-duty assistance; ③ Removing the finished unit from the test bench—handled by the workshop's QD double-girder crane. Kelude's windlass test bench solution includes a dedicated jib crane and protective guards.
Q: How do you load and unload a winch drum on a horizontal lathe?
A: The winch drum (2–6 t, 1–3 m diameter) is loaded onto a horizontal lathe as follows: ① An LD overhead crane lifts the drum and positions it in front of the lathe spindle; ② The drum's center bore is aligned with the spindle center, and the drum is manually pushed onto the spindle; ③ The tailstock center is tightened against the opposite end of the drum; ④ The hook is released to complete loading. Unloading is performed in reverse order. Note: A copper gasket must be placed between the drum and the lathe chuck to prevent damage. Kelude Heavy Industry offers a V-type support frame and guided auxiliary device for this operation.
Q: What are the cleanliness requirements for steering gear gearbox assembly?
A: The assembly accuracy requirements for gears and bearings inside the steering gear gearbox are as follows: ① Cleanliness class — Class 10,000 (ISO Class 7), i.e., no more than 352,000 particles ≥0.5 μm per cubic meter; ② Temperature and humidity — 20–26°C, 40–60% RH; ③ Lifting equipment — chain hoist with a 304 stainless steel dust cover and a fully sealed electric hoist motor to minimize particle generation. Kelude Heavy Industry provides customization service for cleanroom cranes (hermetic motor + stainless steel + anti-static).
