Seven-Roller Universal Fairlead with Upper Roller | Ship Mooring and Towing (ISO 13733 Type 7R)

Product Overview

The ISO 13733 Type 7R universal fairlead is a deck-mounted seven-roller rope guide with two rope-passing openings and an upper roller arrangement. It is used to guide ship mooring or towing lines where the rope lead includes horizontal and vertical direction changes. Rotating roller contact reduces sliding friction at the guide point and helps keep the line within a controlled passage.

The nominal size is based on the outside diameter of the main roller. For nominal sizes 300 and 400, the A / B / C suffix distinguishes different SWL levels while the principal roller dimensions remain the same. Final selection should be coordinated with rope type and diameter, required SWL, line lead angle, standard load direction, roller rotation, shaft and bearing maintenance, deck reinforcement, welding details, and class inspection scope.

Quick Specifications

• Product type: Seven-roller universal fairlead → rolling rope guidance for ship mooring and towing stations.
• Standard and type: ISO 13733 Type 7R → configuration with two rope-passing openings and an upper roller.
• Nominal size range: 140 / 160 / 180 / 200 / 250 / 300A / 300B / 400A / 400B / 400C → selected by main roller diameter and required SWL.
• Main roller outside diameter D1: 139.8 to 406.4 mm → nominal size identifies the approximate main roller outside diameter.
• Rope-passing opening B × H: 195 × 150 to 350 × 250 mm → key clearance for initial rope and line-path checking.
• SWL range: 137 to 1,373 kN, shown as 14 to 140 t in the supplied table → use the standard load rating, not rope MBL, for model selection.
• Calculated weight: 256 to 3,591 kg → relevant to deck handling, transport, foundation planning, and installation sequence.
• Installation focus: Deck-welded structure with rotating rollers → deck reinforcement, weld dimensions, lubrication access, and roller replacement clearance should be confirmed before production.

Main Technical Parameters

Selection & Inquiry Guide

Step 1: Confirm ISO 13733 Type 7R and the required nominal size according to the vessel mooring or towing arrangement.

Step 2: Provide rope type, rope diameter, rope MBL, required fairlead SWL, expected horizontal and vertical lead directions, and the operating line path.

Step 3: For 300A / 300B and 400A / 400B / 400C, select the suffix according to the required SWL; do not select only by roller diameter.

Step 4: Confirm installation position, available deck space, foundation and deck reinforcement, welding interface, nearby equipment clearance, and roller maintenance access.

Step 5: Confirm frame, roller, shaft, bearing or bush material requirements; lubrication arrangement; surface treatment; and corrosion-protection system.

Step 6: Confirm quantity, class society requirement, material traceability, inspection and test scope, delivery destination, required delivery time, and provide the vessel drawing or reference photo if available.

Structure

Seven-roller assembly | Two rope-passing openings | Upper roller | Main guiding rollers | Steel support frame | Roller shafts | Bearings or bushes | Deck-welded base | Lubrication points | Specified surface treatment

Mooring, Towing & Engineering Advantages

• Seven rotating rollers distribute rope contact around the guide path and reduce sliding friction compared with a fixed rope-contact opening.
• Two rope-passing openings provide defined line-routing positions within one fairlead assembly; the approved operating arrangement and load case should be confirmed by the vessel drawing.
• The upper roller helps control the rope path when the line approaches or leaves the fairlead with a vertical lead component, subject to the standard geometry and approved load direction.
• Nominal size is linked to main roller outside diameter, while the letter suffix provides a clear method for selecting different SWL ratings at the same 300 or 400 nominal roller size.
• Roller surfaces, edge transitions, and shaft alignment should be controlled so the rollers rotate freely and do not create sharp local contact on the mooring or towing line.
• Bearing or bush selection, lubrication points, sealing, shaft removal, and roller replacement access should be coordinated with the vessel maintenance plan.
• The deck-welded frame transfers fairlead reactions into the supporting deck structure; foundation reinforcement and weld details should be checked by the shipyard or design office.
• Galvanizing or polished stainless-steel finishing should be applied only where compatible with roller fits, bearing areas, welding interfaces, and the approved material specification.

Custom Attributes

• Standard: ISO 13733 → use when the vessel specification calls for universal fairlead dimensions and SWL ratings from this standard.
• Type: 7R → seven-roller arrangement with two rope-passing openings and an upper roller.
• Nominal Size: 140 to 400C → based on main roller outside diameter, with suffix letters used for different SWL ratings.
• SWL: 137 to 1,373 kN → select from the standard model table and keep separate from rope MBL or breaking load.
• Load Direction: Horizontal and vertical line lead → final permissible direction and reaction basis should follow the standard drawing and vessel arrangement.
• Material: C-Mn steel / mild steel / stainless steel → exact grades for frame, rollers, shafts, and bearing components are to be confirmed.
• Surface Treatment: Sa 2.5 blasting + epoxy shop primer as reference → final coating, galvanizing, or stainless-steel polishing follows project requirement.
• Installation: Deck welded → deck reinforcement, weld size, welding procedure, alignment, and access should be confirmed by approved drawing.
• Certificate Requirement: Available according to project scope → material certificates, maker documentation, class inspection, and witness testing should be agreed before quotation.

How It Works

Mooring or towing line approaches the fairlead → The line enters the selected rope-passing opening → Main and upper rollers rotate as the lead direction changes → Rolling contact guides the line and reduces sliding friction → Fairlead reactions transfer through the welded frame into the reinforced deck structure

Applications

Ship mooring stations | Ship towing stations | Tugboats | Workboats | Cargo vessels | Tankers | Offshore support vessels | Newbuilding projects | Replacement of standard universal fairleads

Certifications & Advantages

Certificates and inspection documentation can be arranged according to project requirement, material traceability, test scope, and class approval procedure. The required certificate level and witness points should be confirmed before quotation.

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

Drawing & Photos

FAQ

Q1: What is the difference between an ISO 13733 Type 7R universal fairlead and a fixed mooring chock?

A1: Type 7R uses seven rotating rollers and two defined rope-passing openings to guide a line through horizontal and vertical lead changes. A fixed chock uses a stationary rope-contact surface. The correct product should follow the vessel mooring or towing arrangement.

Q2: How should 300A / 300B or 400A / 400B / 400C be selected?

A2: Models with the same nominal roller size have the same principal roller diameters but different SWL ratings and calculated weights. Select the suffix according to the required fairlead SWL, standard load case, deck structure, and approved vessel drawing.

Q3: Can both rope-passing openings be loaded at the full listed SWL at the same time?

A3: Simultaneous loading should not be assumed from the model table alone. The operating line arrangement, load directions, combined reactions, deck reinforcement, and approval requirement must be confirmed from the official standard drawing and the vessel-specific engineering calculation.