New offshore service vessel adds value

Nov. 1, 2007
Rigdon Marine Corp. was the first to design platform support vessels (PSVs) with diesel electric propulsion and dynamic positioning class II station-keeping capability.

Rigdon Marine Corp. was the first to design platform support vessels (PSVs) with diesel electric propulsion and dynamic positioning class II station-keeping capability.

Because diesel electric propulsion uses generators and electric motors in lieu of mechanical engines, shafts, large gears, and other ancillary drive train components, it gives flexibility in vessel design. Only an electrical cable is needed to connect the generator power source to the stern and bow electric motor driven propulsion systems. As a result, the vessel can be designed to maximize the cargo systems, which greatly increases the vessel’s marketability and value.

In 2005, Rigdon began to developed a compact, capable vessel with the diesel generator machinery space on the main deck. The company entrusted the design to Guido Perla & Associates who designed the 2004 PSVs. The result is exactly as intended - a vessel with the size, construction cost, and draft to compete on continental shelf drilling programs, yet with the capacities, system redundancy, and station-keeping capabilities to handle most deepwater assignments.

The first Rigdon 400 class PSV,FIRST AND TEN, was delivered in late July.
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Dubbed the Rigdon 4000 class PSV after their large liquid mud capacity, these 10 American Bureau of Shipping (ABS) Classed DPS-2, diesel electric vessels are 190 ft x 46 ft x 18 ft (58 m x 14 m x 5.5 m) and feature three stern drives (two azimuthing and one fixed) and two large forward tunnel thrusters.

The Rigdon 4000 class vessels can transport up to 4,000 bbl of heavy liquid mud in a segregated, self-cleaning oval tank system. The Rigdon oval liquid mud tanks are proven to deliver 100% of their cargo while greatly reducing the expense of tank cleaning, the company says. By contrast, most vessels in the 180 ft to 200 ft (55 m to 61 m) size range constructed in the last three years, including those under construction now, typically hold up to 2,500 bbl of liquid mud and rely on a traditional, square tank design, which is more costly to clean and often results in product loss and degradation.

The first Rigdon 400 class PSV,FIRST AND TEN, was delivered in late July and the remaining nine Rigdon 4000 class vessels will deliver in two month intervals throughout 2008.