Marine Towing Hook | 400 kN Manual-Release Spring Type for Tugboats

Product Overview

The 400 kN manual-release spring towing hook is a shipboard towing fitting used on tugboats and towing vessels to retain the towing connection during operation and permit deliberate local release through a mechanical operating arrangement. The spring-assisted mechanism supports hook opening after the retaining device is disengaged. This page is for the manually operated spring type and does not represent a hydraulic or pneumatic remote-release system.

CB/T 637-1995 covers product classification, technical requirements, test methods, inspection rules, marking, and packing for spring towing hooks used in ship towing. The supplied series ranges from 16 kN to 400 kN, with this page focused on the 400 kN model. The supplied dimensional table uses the term "Max. Load"; the contractual designation as allowable load, SWL, or safe towing load, together with the required release load and test load, must be confirmed from the approved project drawing and class scope before manufacture.

Quick Specifications

• Product type: Manual-release spring towing hook → local mechanical release for ship towing arrangements.
• Standard reference: CB/T 637-1995 → applies to spring towing hooks for ship towing and includes technical, test, inspection, marking, and packing requirements.
• Page model: 400 kN maximum load in the supplied table → highest-capacity model in the provided 16–400 kN series.
• Release arrangement: Manual operation → hydraulic and pneumatic remote-release equipment are not included in this configuration.
• 400 kN model size: L 2259 mm × B 640 mm × H 472 mm → foundation space and operating clearance must be checked before production.
• Calculated weight: approximately 1340.1 kg → relevant to handling, transport, onboard lifting planning, and foundation installation.
• Material basis: Mild steel / C-Mn steel → exact plate, casting, pin, bush, and spring material grades are to be confirmed.
• Surface treatment: Sa 2.5 blasting + one epoxy shop-primer coat as reference → final marine coating follows the vessel painting specification.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm the 400 kN model and state whether the project load is specified as maximum load, allowable load, SWL, or safe towing load.

Step 2: Provide towing-line type, towing eye or connection dimensions, expected lead direction, operating angle, and the required clear hook opening.

Step 3: Confirm the installation foundation, load path, under-deck reinforcement, fastening / welding interface, and available operating clearance by drawing.

Step 4: Confirm the manual release arrangement, local operating position, lever or release-wire route, required release load, and reset procedure.

Step 5: Confirm material grades, minimum design temperature, corrosion environment, ice-class or low-temperature requirement, and final coating system.

Step 6: State test and certificate scope, class society, witness points, quantity, delivery destination, required delivery date, and provide GA or installation drawings.

Structure

Towing hook body | Retaining and latch assembly | Spring-assisted release mechanism | Manual operating lever / release linkage | Pivot pin and bushes | Base and foundation interface | Reset and locking arrangement | Marine protective coating

Release, Installation & Quality Advantages

• The manual mechanism provides local mechanical operation without relying on a hydraulic power pack or pneumatic supply; the operator position and safe access must be checked in the vessel arrangement.
• Spring assistance supports hook opening after the latch is disengaged, while the permitted release load must be demonstrated by the approved design and test procedure rather than assumed from the 400 kN table value.
• The 400 kN model provides a defined dimensional envelope for deck-layout review, foundation design, access planning, and quotation comparison.
• The towing force is transferred through the hook body, pivot, base, and supporting hull structure; foundation strength and under-deck reinforcement are therefore part of the complete towing arrangement.
• Pins, bushes, latch contact areas, springs, and release linkages should remain accessible for inspection, lubrication, wear checks, and functional testing.
• Load testing, release-operation testing, material traceability, and class witnessing can be arranged according to the approved inspection and test plan.

Custom Attributes

• Standard: CB/T 637-1995 → standard reference for spring towing hooks used in ship towing.
• Model: 400 → selected from the supplied 16 / 25 / 40 / 63 / 100 / 160 / 220 / 320 / 400 kN series.
• Load Rating: 400 kN maximum load in supplied data → final contractual load definition and marking to be confirmed.
• Release Method: Manual local release → remote hydraulic or pneumatic release is outside this model unless separately designed.
• Material: Mild steel / C-Mn steel → exact component grades and low-temperature requirements to be confirmed.
• Surface Treatment: Sa 2.5 + epoxy shop primer as reference → final paint system follows project specification.
• Installation: Deck / foundation mounted → load direction, fastening details, deck reinforcement, and access clearance require approved drawings.
• Inspection & Certification: According to order scope → test loads, release test condition, class witnessing, and certificate type must be agreed before quotation.

How It Works

Towing connection is placed on the hook → Retaining mechanism secures the hook in the working position → Towing load is transferred to the base and supporting hull structure → Operator actuates the manual release arrangement → Latch disengages and the spring assists hook opening → Connection is released → Hook is reset, locked, and function-checked before reuse

Applications

Harbour tugboats | Coastal towing vessels | Ship-assist tugs | Workboats with approved towing arrangements | Newbuilding projects | Replacement of compatible spring towing hooks

Certifications & Advantages

Certificates and inspection can be arranged according to project requirement, approved test scope, material traceability, and classification society procedure. Availability is subject to class approval and the agreed order scope.

Certification: CCS, NK, BV, ABS, DNV, LR, KR, IRS, RS, RINA, CRS, Makers Test Certificate.

Drawing & Photos

FAQ

Q1: Can the hook be manually released while carrying the full 400 kN load?

A1: The supplied table identifies 400 kN as the maximum load, but it does not independently confirm the permitted release load. Release under load must be defined in the approved specification and verified by the required release-operation test. It should not be assumed that full-load release is included.

Q2: Does this model include wheelhouse remote release?

A2: No. This page describes a manual-release spring towing hook. A hydraulic or pneumatic remote-release system requires a different approved configuration, control philosophy, fail-safe review, and test scope.

Q3: What information is required before quotation?

A3: Provide the required load designation, towing-line or eye dimensions, pull direction, foundation and installation drawing, manual release arrangement, material and coating requirements, class society, test scope, quantity, destination, and delivery schedule.