The INTERCON COUPLER SYSTEM provides a safe and efficient solution to the problems of connecting tugs and barges in ocean and coastwise pushing operations. Principal benefits include the ability to push in the widest range of sea states; the complete elimination of hull contact; fail-safe mechanical connection with redundant controls, and elimination of the expense and hazards of towing lines and related equipment. In simplest form, the patented Intercon Coupler System provides a single degree of freedom allowing the tug to pitch about a transverse connection between the tug and barge. All other motions are restrained so that tug motions match barge motions in roll and heave. The connection is mechanical – accomplished with two independently mounted ram assemblies, gear driven, and configured for tug installation. The rams stroke transversely, engaging the vertical ladder structures incorporated into both walls of the stern notch. The resulting tug-barge connection is rigid and mechanically locked.
Tug-Barge Couplers – Design & Construction
The Intercon Coupler System ram assembly is equipped with a cast steel interface head (helmet) which incorporates a multi-tooth profile. The helmet is mounted on a forged steel spherical support (ball) which is designed to allow automatic alignment during engagement yet retain the greatest load bearing capacity in a minimum space. Rotation, caused by tug pitch, is transmitted to the ram by anti-rotation pins that connect the helmet and ball. Ram rotation is carried by a either a bronze or an Orkot® bushing which is installed in the cylindrical ram housing. All other relative motions are restricted. The extension and retraction of the ram assembly is accomplished by an alloy threaded shaft turning in a bronze threaded boss incorporated into the inboard end of the ram assembly. The screw is actuated by electric motors driving through gear reduction mounted on the interior end of the housing assembly. The screw can be actuated in both high speed and low speed modes. In low speed mode, extension force exceeds 260,000 lbs. on each ram. Auxiliary hydraulic drive motors are optionally available. The transverse thrust from the actuator screw assembly is carried by a roller type thrust bearing rated in excess of the worst condition athwartship loads revealed in model tank tests. A load cell is incorporated into the bearing housing to monitor thrust forces.
The Intercon Coupler System has been designed to meet severe operating conditions. These criteria and operating load parameters were tested by computer simulation, and dynamic tank testing at the Netherlands Ship Model Basin. These initial tank tests utilized models of a 260,000 barrel capacity barge pushed by a 6000 HP class tug equipped with lateral connecting rams simulating the Intercon design. Load tests were conducted in 22 ft. mean seas, and included various wave heights in the spectrum. Substantial data was generated by wave heights, periods, and directions; these results guided the final engineering phase of the Intercon System. Subsequent to the initial testing – continued model testing has been conducted to verify coupler sizing on new applications. Upon review of the design and NSMB test data, the U.S. Coast Guard approved the Intercon Coupler System for Dual Mode tug-barge service as defined by USCG NAVIC 2-81.
The rotating ram components are comprised of rolled steel and structural plate, all fabricated and machined as a one-piece cylinder. The outside diameter of the ram is clad with corrosion resistant stainless steel. The ram housing is fabricated and machined as a single weldment. The housing is provided with circumferential flanges and longitudinal ribs spaced to accommodate design loads. The ram housings are incorporated into complete “load box” modules – port and starboard – which become part of the hull structure. The load box weldments are thermally stress relieved, and machined to receive all coupler components. All mechanical and electrical assembly is completed and tested at Intercon’s plant prior to shipment. Load box modules are designed and fabricated to match exactly with surrounding hull structure, allowing the Intercon System to be easily adapted for both retrofit and new construction.
Tug-Barge Couplers – Installation
As a part of the Intercon Coupler System, customers are furnished ladder members for installation in the barge notch walls. Alternatively, skeg modules can be fabricated at Intercon, with the complete ladder section incorporated. The ladder members provide a continuous tooth pattern on the fore and aft sides of the section, designed to engage the ram’s helmet, and thereby lock the tug’s vertical motion relative to the barge. The side taper is relatively flat to minimize resultant thrust from bow to stern sway loads. The tooth profiles are of equal angle, and peaked to balance forces and minimize multi-angle planes of contact when connected. Ladder vertical length can vary from 15 ft. to 50 ft., eliminating the need for ballasting either vessel when entering the notch. When engaged, the Intercon Coupler System fully eliminates hull to hull contact between tug and barge, permitting the tug to pitch freely relative to the barge. Crew fatigue is lessened given smoother tug motions afforded by the pitchline being aligned with living areas. With the ability to retract the interface heads within the hull envelope, the Intercon System avoids dangerous, fixed projections on both the tug and barge. This feature also preserves fleet interchangeability. Tugs equipped with the Intercon Coupler System can conventionally push or tow non-System barges, and conversely, non-Intercon Coupler System tugs can work with ladder equipped barges. Each vessel retains its ability to operate as any vessel in its respective class.
Tug-Barge Couplers – System Operations
The Intercon Coupler System is typically monitored and controlled from the upper wheelhouse using a touch screen controller. A secondary touch screen controller as well as auxiliary manual controls are located in the coupler room. When engaged, the Intercon Coupler System fully eliminates hull to hull contact between tug and barge, permitting the tug to pitch freely relative to the barge. The ram axis is typically aligned with crew living areas to provide smoother motion which lessens crew fatigue. With the ability to retract the interface heads within the hull envelope, the Intercon Coupler System avoids dangerous, fixed projections on both the tug and barge. This feature also preserves fleet interchangeability. Tugs equipped with the Intercon Coupler System can conventionally push or tow non-System barges, and conversely, non-Intercon Coupler System tugs can work with ladder equipped barges. Each vessel retains its ability to operate as any vessel in its respective class.
Tug-Barge Couplers – Advantages
The favorable economics of the Intercon Coupler System result from several factors, but essentially center on speed. This Coupler can produce speed advantages of 35% compared to towed units in average conditions. The ability to pitch maintains propeller and steering efficiency in any sea direction and condition so the tug can stay safely in the notch – pushing – while other units are towing or weatherbound. The Intercon Tug-Barge Coupler is the result of thorough analysis of today’s tug-barge operations. The demands of the application, as well as the limitations of alternate linkage technology, were all considered in the development of this System.
- Permits pushing in a wide range of sea conditions
- Increases speeds 35-40% over towed units
- Fuel savings enhanced by wheel and rudder efficiencies
- Fully eliminates hull contact between tug and barge
- Fail-safe mechanical connection with force monitoring
- Engagement allowed regardless of draft or trim
- Fabricated construction allows retrofit on existing conventional tugs and barges
- Mechanical drive with engagement safeguards – not vulnerable to hydraulic or pneumatic system failures
- Engaged and disengaged without crew on deck
- Eliminates expense and hazards of hawsers, headlines, and cables
- Comfortable ride resulting in less crew fatigue
- Fleet interchangeability due to flush mounted components
- Unmatched maneuverability at sea, and in port
- USCG approved for Dual Mode under NAVIC 2-81
- Worldwide product support from Intercon’s service facilities
- Designed and manufactured in America by one of the leading names in marine equipment
The Intercon Coupler not only provides the economies of pushing, but offers flexibility, speed capabilities, improved transit predictability, and a degree of safety in operation not found in traditional tug-barge operations.
Tug-Barge Couplers – Vessel List
Intercon Coupler Systems Reference
Tug-Barge Couplers – Models
Intercon ATB couplers are available in a range of sizes allowing efficient and safe matching of tugs and barges. Tug characteristics – displacement and length, in particular – are the primary data needed for connection load analysis, and coupler selection.
Intercon Coupler Nominal Data
|SEAFARER||24 in.||34 in.||50 in.||64 in.||72 in.|
|CAPT. FRED BOUCHARD||89,000 lbs.||100,000 lbs.||225,000 lbs.||325,000 lbs.||400,000 lbs.|
|MORTON S. BOUCHARD IV||C-Drive||C-Drive||Standard Drive or C-Drive||Standard Drive or C-Drive||Standard Drive or C-Drive|
|DANIELLE BOUCHARD||C-Drive||C-Drive||Standard Drive or C-Drive||Standard Drive or C-Drive||Standard Drive or C-Drive|
|Interface Head Options||Hex-Tooth||Hex-Tooth||Multi-Tooth or Tooth-Friction or Wave||Multi-Tooth or Tooth-Friction or Wave||Multi-Tooth or Tooth-Friction or Wave|
|Engaged Force Generated||100,000 lbs.||200,000 lbs.||300,000 lbs.||300,000 lbs.||300,000 lbs.|
|Rate of Travel||30 IPM||46 IPM||150 IPM||118 IPM||118 IPM|
|Minimum Installation Envelope(Tug)|
|Beam||24 ft.||27 ft.||32 ft.||36 ft.||41 ft.|
|Height||8 ft.||8 ft.||8 ft.||8 ft.||10 ft.|
|Bow to Stern||8 ft.||8 ft.||12 ft.||12 ft.||12 ft.|
Intercon couplers can be customized for various types of service. There are four basic styles of interface heads that mount to the ram and provide connection to a barge’s ladder surfaces.
• Hex-Tooth – Standard interface head for Model 24 and Model 34 couplers. The hex-tooth profile provides a fixed connection between the vessels. It is used where lightering is not required.
• Multi-Tooth – Standard interface head for Model 50 and higher couplers. The multi-tooth profile provides a fixed connection between the vessels. It is used where lightering is not required.
• Tooth-Friction – Provides the fixed tooth performance, but also allows for lightering by rotating the helmet 90 degrees in calm water and reconnecting utilizing a smooth friction interface. Sea state restrictions apply to the friction mode.
• Wave – Provides secure unrestricted service, while allowing lightering operations without complete disconnection from the barge. This connection style requires Intercon’s C-Drive actuation.
Two types of coupler drives are offered. The Standard Drive (multi-motor) style incorporates a high speed motor for rapid ram travel, and a low speed motor to develop high engagement forces at a slower travel. The C-Drive style incorporates one electric motor for rapid travel which provides initial engagement. Hydraulic pressure then develops high engagement forces. Both types of drive provide mechanical engagement to keep the vessels connected even if power is lost.
Intercon welcomes your inquiry regarding the type of connection and drive that would best serve your ATB mission. Application analysis, coupler sizing, and model testing support, if needed, are provided by Intercon’s Engineering Department.