Turnbuckles
Dock Open Body Turnbuckle (Jaw & Jaw Type) — Jaw & Jaw (SWL 3.5T - P Grade)
Heavy-duty dock open-body turnbuckle with jaw-and-jaw ends, clevis pins and cotter pins, rated SWL 3.5 ton (3500 kg) P grade. Electro-galvanized finish—185 mm adjustment range (L1 445 mm / L2 630 mm) for shipyard, port and marine lashings.
Request a Quote1. Product Overview
This is a high-capacity heavy-duty dock open-body turnbuckle (marine turnbuckle / rigging tensioner) designed for ships, ports and shipyard work, with jaw-and-jaw (double fork / double U-type) ends at both sides. Safe working load (SWL) is 3.5 tons (3500 kg) at P grade strength level. Built to marine heavy-rigging practice, each end uses a high-strength forged fork, cross pin and cotter pin for secure closed connections. Rotation of the open center frame drives opposite-hand threaded rods to extend or retract together for high-precision straight-line tensioning and span adjustment on dock stays, vessel lashings and permanent port mooring lines. Long adjustment travel with full electro-galvanized protection suits harsh salt-spray environments.
2. Key Features & Design Highlights
- Marine open-body frame: Strong open oval body with a central window—dock and port crews can visually inspect thread engagement on both rods during routine patrols to verify safe thread length at source.
- Lock jam nuts: Hex jam nuts at both frame ends—after tension is set, lock the nuts against the body to prevent rod creep from wave vibration or sustained wind load.
- Opposite-hand threads: Left and right internal threads in the frame—turn the body clockwise or counter-clockwise to tighten or loosen both ends simultaneously.
- Jaw & Jaw ends: Classic U-fork jaws with heavy forged cross pins and cotter pins at both ends—closed connections that will not open under multi-directional pull, unlike open hooks. Fits deck pad eyes, wall lugs, stainless tie rods and swaged wire rope eyes.
- SWL 3.5T, P grade: 3500 kg safe working load at P grade—excellent fatigue and deformation resistance under long-term high-stress tension with ample safety margin.
- Long travel, L1/L2: Closed length L1 445 mm, open length L2 630 mm—185 mm effective adjustment for long-span stay systems. Electro-galvanized finish resists coastal salt spray and humidity.
3. Primary Applications
- Shipyard and dock gate protection nets, positioning cables and port machinery anti-wind stays.
- Vessel deck lashings for large containers, heavy equipment and specialty vehicles on cargo and work vessels—secure under heavy sea motion.
- Coastal building steel bracing, seawall nets and shore-side structural cable tensioning.
- Quay crane towers, temporary shore cranes and antenna guy wires at ground anchor terminals.
4. Specifications
| Product Type | Dock open-body jaw & jaw turnbuckle |
|---|---|
| End Fittings | Jaw & Jaw (double fork with pin and cotter pin) |
| Strength Grade | P grade |
| Safe Working Load (SWL) | 3.5 T (3.5 TON / 3500 kg) |
| Closed Length (L1) | 445 mm (rods fully retracted) |
| Open Length (L2) | 630 mm (rods at safe maximum extension) |
| Adjustment Travel | 185 mm (L2 − L1) |
| Finish | Electro-galvanized (bright silver, salt-spray resistant) |
| Locking | Jam nuts at both ends; cotter pins on cross pins |
| Adjustment | Center body rotation, opposite-hand threads |
Safety Guidelines
- Not for vertical lifting—SWL 3.5T P grade is for tensioning and mooring only. Do not use as a crane hook terminal, hoist assembly or manned lift component.
- Install cotter pins correctly—after inserting each cross pin, fit and spread the cotter pin fully. Never substitute wire for cotter pins; vibration can eject the pin and fail the connection.
- Lock jam nuts after adjustment—when target tension is reached, tighten both hex jam nuts against the frame with a wrench. This is essential to hold tension under long-term vibration.
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