JAK® Coupling

The JAK® ATB Coupling System of Beacon Finland is invented and developed especially for use on Articulated Tug Barge (ATB) systems. It is a modern innovation with significant advantages with regard to space, weight and cost.

The original invention was made in 1991. Since then, Beacon Finland has continued to develop it into a very competitive product for the ATB market.

The basic idea of the invention was to improve the existing connection devices between the tug and the barge in the ATB-system with the aim of a lightweight, safe, simple and cost effective coupling. The JAK®-ATB Coupling System solved the conventional problems and fulfilled the basic targets more than well.

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The JAK®-ATB Coupling System is a pneumatically actuated electrically controlled articulated tug-barge connecting system. The coupling action is controlled from a control panel on the vessel's bridge or/and from the local control panel in the coupler unit compartment.

The efficiency and the reasonable cost of the coupling device are based on its simple construction. There are also several other benefits of this system, e.g.:

  • Cost efficient due to simple construction and installation
  • Environmentally friendly due to pneumatic operation and lubrication with environmental friendly oil
  • Ease of operation due to simple control and less need and ease of maintenance
  • No on-deck equipment and little space demand under deck
  • Small power demand as the power consumption is only 5kW. The system utilizes the existing power and compressed air supply of the tug. (24V DC supply & compressed air (425 psi) supply)

JAK® "Lightering System"

Beacon Finland Ltd has developed the capability of the JAK® ATB Coupling System so that the Tug remains in the notch of the Barge during loading and unloading operations. The method is simple, whereby the Coupling System's Pins remain extended in the verticle grooves of the Socket Plates, port and starboard, allowing the Barge to move vertically, up or down.

JAK® "Hydralok System"

Beacon Finland's JAK® "Hydralok" is a Hydraulic Interlock System which is an attachment for the Pneumatically operated JAK® ATB Coupling System. The Hydralok's purpose is to significantly reduce, or possibly eliminate the horizontal movement of the Tug while engaged with the Barge by locking the Main Coupling Pins, while in the extended position.

Scope of Supply

Application Design

The scope of supply includes the required application design, which is started already in the quotation phase and is based on inquiry data. Beacon Finland is providing the classification drawings for both the tug and the barge, as well for the hull construction as for the installation of the JAK system. Strength analysis utilizing finite element calculations are also performed.

Hardware & Instructions

The following equipment is included in a typical Scope of Supply:

  • Coupler Units (2 pcs)
  • Guide & Socket Plate Assembly (2 pcs)
  • Pneumatic Valve Panel
  • Control System
  • Instructions (installation & operation)

Additional Services

The following Services are not included in the Scope of Supply:

  • Workshop Drawings
  • Ship Check and Measurement Verification of existing tug and barge (obligatory)
  • Training of operating personnel

Beacon Finland can on request provide the Additional Services mentioned above.


Tested for Reliability
The pin-load has been model tested on a model tug-barge system at the ship model basin of VTT - the Technical Research Center of Finland in different sea-states, speeds and angles of attack. The results are applied for each tug-barge combination to establish the applicable sea-state limits.

The JAK®-coupling comes in two basic models, the standard P-type is pneumatically actuated and electrically controlled. There is also a hydraulically actuated and electrically controlled H-type available.

JAK®-ATB Coupling System includes product versions adapted to various tug-barge/sea state combinations, dependent on:

  • Pusher engine power
  • Barge displacement
  • Operational circumstances

There are five sizes available: the JAK®-100, the JAK®-200, the JAK®-400, the JAK®-700 and the JAK®-1000. See separate specification table.

JAK® -ATB Coupling Comes in 5 Sizes

ATB Coupling Size Tug Displacement
Tug Main Engine Power (hp)
Barge Displacement (tons)
JAK®-100 50–150 350–750 200–1 000
JAK®-200 100–500 500-2 500 500–8 000
JAK®-400 350–1 000 600–6 000 1 000–25 000
JAK®-700 650–1 800 2 000–7 000 10 000–30 000
JAK®-1000 1 500–2 500 5 000–10 000 20 000–35 000

NB: Table values are for approximation purposes only

Basic Values

Coupling Size Max. Significant Wave Height (m) Typical Operational Area
JAK®-100 up to 2 Sheltered Waters
JAK®-200 up to 5 Rivers, Lakes
JAK®-400 up to 7 Coastal
JAK®-700 up to 7 Offshore, Coastal
JAK®-1000 up to 7 Offshore, Coastal

Installation of the JAK®-Coupling

The JAK®-coupler unit is mounted by welding the housing to the hull structures of the pusher (SB- and PS-side), directly under deck.

The socket plates, including guide plates - the counterparts of the cylinders - are welded to the SB - and PS-sides of the notch of the barge.

The location of the couplers in the bow makes it necessary to construct a blister to level the coupler units and to fit the pusher into the notch. Being rather small, the casing will normally not increase the vessel's total breadth.

Modification of Existing Barges

To enable the connection, existing barges need to be modified by adding a notch for the tug bow at the stern end of the barge.

No electrical installations on the barge are necessary nor any piping.

The barge will need to be re-classified, which will require some calculations.

Rules & Regulations

Terminology of Tug Barge Connections

Common IMO Terminology
Classification Society Articulated
Tug Barge (ATB)
Tug Barge (ITB)
Det Norske Veritas (DNV) DNV Type II DNV Type I
American Bureau of Shipping (ABS);
US Coast Guard (USCG)
Integrated Tug Barge (ITB)
Dual Mode (DM) Pushing Mode (PM)
Articulated Connection Rigid Connection

The JAK®-ATB Coupling System installations have been accepted by the following classification societies:

  • ABS (American Bureau of Shipping) as ITB (Integrated Tug Barge): Dual Mode (DM) / Articulated Connection
  • LRS (Lloyd's Register of Shipping)

The JAK®-Coupling system and equipment can be modified to meet the requirements of the Flag authority and local Classification society.

JAK-Inquiry Form

In order to enable us to provide you with an accurate and realistic offer, at least the following data need to be included in the request for proposal:

Pusher (Tug) data:
Length over all
Bow shape
Propulsion system
General Arrangement Plan (at least of the fore ship area)
Max. Size: 2000kb Extensions: jpg, gif, jpeg, pdf, png
Lines Plan (at least of the bow fore ship area)
Max. Size: 2000kb Extensions: jpg, gif, jpeg, pdf, png
Barge Data:
Length over all
Required draught range (min. ballast draught; max. loaded draught)
General Arrangement Plan (at least aft area)
Max. Size: 2000kb Extensions: jpg, gif,jpeg, pdf, png
Lines Plan (at least aft area)
Max. Size: 2000kb Extensions: jpg, gif, jpeg, pdf, png
Common Data:
Classification Society and class notation
Flag authority
Operating sea area
Operating sea state
Required delivery time and delivery address (shipyard)
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