Ocean Tug & Barge Engineering rethinks the PSV

Ocean Tug & Barge Engineering Corp., is pleased to present the first major rethink of the offshore supply vessel concept in over 40 years – the “PROVIDER” class AT/B supply vessel. First developed by OT&BE in 2004, and in development since that time with Ship Architects, Inc. the PROVIDER has been designed to bring the same cost savings and flexibility to the offshore supply business, as it has brought to other sectors of the transportation business. The PROVIDER is a true revolution in offshore supply vessel design. The new concept is based on proven AT/B and PSV technology, married for the first time in a vessel whose flexibility and application is almost without limit. The design comes from the most experienced AT/B designer in the hemisphere and leverages over 32 years experience in AT/B design. The major improvements over a conventional PSV and the design goals that brought us here, are numerous and highly attractive:

•Increased Deadweight Capacity Per Unit Length
•Increased Deck Area, Virtually Unobstructed Over A Longer Length
•Reduced Building Cost Per DWT
•Reduced Crew Cost
•Wider Number of Shipyard Choices
•Sizes For Both Deepwater and Inshore Operations
•Lighter Drafts, Allowing Access To Less Improved Ports
•High Residual Value
•Total Flexibility in Size To Suit Mission, With Navy-Inspired Deck Mounting Capability for
Different Equipment
•Increased Flexibility During Business Slowdowns
•Easily Modified for Increasing or Decreasing Size
•Multiple Barges, A Smaller Number of Tugs Possible – Lower Capital/DWT By 60%
•Multiple Specialty Barges Can Be Built Without Building New Engine Rooms
•Extremely and Quickly Adaptable to The Changing Marketplace
•Power Unit/ Crew Keeps Moving For A Higher Utilization of the Expense Portion of The
•Reduced Crew Size for Easier Manning/Hiring
•High End Accommodation
•Diesel-Electric/Hybrid Capable Drive Featuring ASD Tugs
•Speeds 12 Knots and Upward Possible

•Simpler Drydocking and Repair/Replacement of Damaged Unit
•Seaworthiness to 8M Significant Height Seas
•Fully Functional Ocean Tugs That Are Tow-Capable
•Barges Adaptable to Many Services Outside the Offshore Industry
•Lower Regulatory Burden
•Fully DP-2 Capable
•Increased Maneuverability, Especially In Heavy Weather

The design series can accommodate a range of tug sizes from 1,800 to 12,000 HP and higher and barge sizes from 1,000 to 15,000 dwt.

Increased Deadweight Capacity Per Unit Length

Because the barge does not have to carry a major machinery and hotel plant, the majority of the barge’s displacement is devoted to cargo. Comparing a 250’ PROVIDER barge, and a 250’ PSV, of the same beam and draft, the difference in carrying capacity can be as much as 40%. This means one vessel can easily service multiple rigs, or carry more at a time to one rig.

Increased Deck Area, Virtually Unobstructed Over A Longer Length

Virtually the entire length of the barge is open deck. The tug Master always operates from his normal conning position and with Z-drives, and DP capability, the unit can operate with the same capability as a self-propelled PSV.

Reduced Building Cost Per DWT

Because the tugs and barges are built in specialized yards and are designed as true tug/barge units, the cost to construct per DWT capacity will be lower than for the single large PSV, and the same cost as a smaller one. It is even possible, with OT&BE’s long design experience and capabilities, to refit existing tugs and barges to this service.

Reduced Crew Cost

The crew of the tug, based on the US Domestic Tonnage, will be smaller that that required for the self-propelled boat. The tug is however, capable of carrying a larger crew if desired by the Owner. Also, the barge is considered unmanned and has a loadline based on this, with a 25% freeboard reduction allowed, and no crew.

Wider Number of Shipyard Choices

Especially in larger units, there are more yards available to build the tug and the barge, in more places. Both ocean and inland yards can produce this design, in all its’ sizes and variants.

Sizes For Both Deepwater and Inshore Operations

The PROVIDER has 4 basic size tugs, 65’-1800HP, 85’-3000 HP, 105’-4,000 HP and 116’-6000 HP. Large sizes can be built, all the way up to 12,000 HP. Barges are designed in beam increments of 42’, 54’, 64’ and 72’, and can be built to virtually any length.

Lighter Drafts, Allowing Access To Less Improved Ports

The PROVIDER class has barges that draw from as little as 9 feet for inshore operation, to 12- 14 feet for deepwater operation. Deeper drafts are also possible. This means that unlike larger deep-draft boats, even the largest barges can enter ports without deep water.

High Residual Value

Unlike self-propelled PSV’s which have a somewhat limited resale market, the PROVIDER class unit has added flexibility that brings a higher residual value. The design is flexible enough that the unit can carry containers, be adapted to liquid cargoes of larger DWT than a comparable PSV, be employed as a deck unit to move ro-ro and other cargoes, and can have a house constructed on deck for carrying cargo requiring protection. The tugs are stand-alone Z-drive tug, designed to be easily adaptable to other missions such as ship docking, towing, or other types of AT/B service.

Total Flexibility in Size To Suit Mission

Following the Navv’s lead in designing “platforms” capable of a wide rang of missions, simply by adding and removing modular systems and machinery needed for any specific mission, the PROVIDER class can be modified inexpensively to suit virtually any requirement. Using various mounting schemes
adaptable to most machinery or storage systems, the barge can be changed in a matter of days, from one mission to another, and back again. Facilities needed to do so are limited in availability only by crane capacity. Mud tanks, water tanks, and other storage tanks and machinery is easily installed below deck or even on deck in some cases.

Increased Flexibility During Business Slowdowns

The units’ adaptability and mission flexibility means that during offshore slowdowns, the tug and barge can move containers, deck cargo, etc., along any coast with virtually no modification. In addition, a new barge can be constructed for the tug to push for a specialized alternative operation where a specialized cargo unit is required. This can be done without tying the tug up for extended periods, as it will virtually never need modification, and can continue to earn for the Owners.

Easily Modified for Increasing or Decreasing Size

The barges are designed around basic building blocks of length, that allow for multiple sizes designed to meet the Owner’s requirements. If those requirements change, the hull modules can be built fairly quickly and added into the barge in a relatively short time. The unit remains in service until the new module is built, then spends a relatively short time in drydock to install it. The tug meanwhile, can continue to work with other barges in the fleet until the modified barge is ready. This is not possible with a self-propelled vessel. The reverse can be done if a barge is too big for a charter.

Multiple Barges, A Smaller Number of Tugs Possible – Lower Capital/DWT By 60%

The PROVIDER is a perfect application for “drop and swap” operation where one tug can be assigned to multiple barges. For example, a tug can bring in an empty barge to the sea buoy, and have a smaller towboat take it into port to be re-loaded. The AT/B tug can take a loaded barge from the towboat or shift boat, and head right back out to the rigs. Multiple barges can be loading without the tug needing to be there. This increased utilization of the “expense” part of the unit means lower long term costs and less crew required. Also, in an emergency, for those operations where there is no weather issue or DP required, a conventional tug can push the AT/B barge with conventional push gear.

Extremely and Quickly Adaptable to The Changing Marketplace

The entire fleet can be designed to be made interchangeable with all tugs able to handle all barges, if desired. Business that requires a 250 foot barge, but may have a low speed requirement, can be handled by a tug of lower size and HP, saving fuel and associated costs, when normally a 3000 HP tug handles that same barge.

Power Unit/ Crew Keeps Moving For A Higher Utilization of the Expense Portion of The Unit

Again, using drop and swap, the tug and its’ crew can keep working and running to the rigs while another barge is in port loading. There is no need to keep the tug tied up and waiting.

Reduced Crew Size for Easier Manning/Hiring

A typical crew size for an AT/B is driven by the domestic GRT of the tug. This can run from 5 to 9 crew. This means that depending on route, and Owner preference, a smaller crew than an PSV may be possible. ALSO – because of the larger cargo capacity, as well as the drop & swap possibility , the number of crew needed to move a given yearly quantity of cargo is far less than a self-propelled unit because the productivity of the crew is so high.

High End Accommodation

The accommodations on our AT/B designs are of a very high standard, as evidenced by the crew satisfaction record of our tugs. The accommodations will equal those found on many PSV’s and can be designed to even higher standards. All of our tugs will meet IMO requirements for sound levels..

Diesel-Electric/Hybrid Capable Drive

The PROVIDER class boats will have an EcoMarine Diesel-electric/hybrid drive system available as standard, but can be fitted with any type of drive available. The system will be easy to maintain, more flexible than traditional marine electric drives and more emissions/fuel efficient, especially in the hybrid versions. Some versions of the designs also allow for a greatly improved, conventional Z-drive arrangement using a unique engine arrangement developed by OT&BE.

Speeds 12 Knots and Upward Possible

Using the extensive R&D we have done into barge and tug design as it relates to speed, the PROVIDER class units can be designed to exceed 12 knots in service, and even higher if required.

Simpler Drydocking and Repair/Replacement of Damaged Unit

The tug and barge can be drydocked for repair and inspection in a larger number of locations than the PSV. This is especially true of the tug, as compared to large, deepwater PSV’s. Each unit can run without the other if required, with the tug pushing another barge of the fleet, or a barge handled by another tug.

Seaworthiness to 8M Significant Height Seas

The AT/B of comparable size can operate in this service in the same seas in the Gulf that even the largest PSV’s can work in.

Fully Functional Ocean Tugs That Are Tow-Capable

The PROVIDER class tugs are true ocean or coastal tugs, designed to be capable of independent operation, in services tugs provide. The tug can be designed with a towing winch, or with other features to assure its’ flexibility.

Fully DP-2 Capable

The combined unit can be designed to be fully capable to DP-2 and flexible enough to meet future requirements.

Increased Maneuverability, Especially In Heavy Weather

The maneuverability of the AT/B is not diminished in heavy seas. The propellers of the tug, hinged in the notch, will be less likely to come out of the water in heavy seas, improving steerability and propulsion.

OT&BE is currently working with major suppliers of offshore support vessel equipment to provide the very best options possible for the PROVIDER class designs. Discussions are currently underway with a number of companies for deployment of the AT/B PSV in the near future.

By Professional Mariner Staff