Marine Link
Tuesday, November 21, 2017

Crewboat/OSV Focus

December 6, 2000

Thoma-Sea Launches New OSV for Massie

Thoma-Sea Boatbuilders Inc., Houma, La., launched the first of two new 150-ft. offshore supply vessels (OSVs) it is building for Massie Towing of Houma. The vessels were designed by Frank Basil of Intech & Associates, also of Houma.

The first vessel, M1, entered service in mid-June, and the second vessel is scheduled to launch in December 2000. Massie will operate both vessels in the Gulf of Mexico.

Propulsion power for the two new OSVs comes from twin Cat 3508EUI marine engines, each rated 905 bhp (675 bkW) at 1,600 rpm. The electronic unit injected 3508s drive Bird Johnson 72 x 59 in. propellers through Twin Disc 5:1 gears, providing a service speed of 14 knots. Thoma-Sea’s local Cat Dealer, Louisiana Power Systems of Morgan City, La., is providing all engines and marine gears for the vessels.

“We’ve had good success with Cat 3500 engines, and we have a good working relationship with Louisiana Power Systems,” says Robert Thomassie Sr., Thoma-Sea’s owner. “When we need anything - whether it’s to verify proper cooler size or adapt a PTO drive to accept a different pump - they do it without delay and they don’t gripe about it.”

The M1 is equipped with a Schottel bow thruster powered by a Cat 3406C rated 300 bhp (254 bkW) at 1,800 rpm. Fire-fighting capability is added with a Crane Deming 2,000 gpm fire pump driven by the 3406’s front PTO. Three-phase electrical power is provided by two Cat 3306B gen sets rated 95 ekW at 1,200 rpm.

The vessels have 2,646 sq. ft. of deck cargo area. Tank capacities include: 1,100 barrels liquid mud, 90,648 gallons fuel, 112,492 gallons fresh water, 14,430 gallons potable water, 1,297 gallons sewage, and three similarly sized tanks totaling 2,354 gallons (8,922 L) for bilge water, dirty oil and clean lube oil.

Eastern Shipbuilding Delivers OSV

Eastern Shipbuilding Group recently delivered the OSV San Rafael to Naviera Ramaulipas, S.A. de C.V. of Tampico, Mexico for operations in the Bahia de Campeche (Bay of Campeche) oil fields off Eastern Mexico. This highly sophisticated 204 x 44 x 16 ft. offshore supply vessel is equipped with the latest in propulsion equipment and control systems.

The propulsion plant consists of a pair of Caterpillar 3516B main engines rated at 2,000 hp each @ 1,600 rpm, complete with Caterpilllar Engine Vision alarm and Monitoring Systems, coupled to Reintjes WAF-862 gearboxes with 96-in. diameter four-blade stainless steel propellers. Special equipment includes a 100 hp Thrustmaster retractable tunnel/azimuthing bowthruster powered by a Caterpillar 3508B engine, high lift style independent rudders, 6,600 gpm Skum fire monitor capable of over 450 ft. reach and a Konesberg/Simrad SDPO1 Dynamic Positioning systems with Joystick Autopilot.

Eastern's local Caterpillar dealer, Thompson Tractor of Mobile, Ala. provided all of the main and auxiliary engines, while the Reintjes gears were provided by Karl Senner of New Orleans, La. Engineering was provided by Design Associates, Inc. of New Orleans.

Capacities include 110,000 gals. of fuel, 211,000 gals. of drill water/ballast, 7,200 cu. ft. of bulk in six tanks and 3,012 barrels of liquid mud. The San Rafael is certified by American Bureau Shipping Maltese Cross A1 Maltese Cross AMS, Ocean Service, with full International SOLAS certificate.

German Company Unveils SWATH Vessel

Germany’s Abeking & Rasmussen presented its SWATH vessel concept under the brand SWATH@A&R at the recent SMM Exhibition in Hamburg, Germany, a unique vessel concept designed for a number of uses, including pilot boat, search and rescue, as well as crewboat and offshore support vessel.

In fact, in the latter case, the boat design is being touted as attractive to offshore users due to its inherently stable design and capability in working in Sea States that could leave similar monohull vessels at the docks.

Also, when the weather does become a factor, A&R contends that its design is faster than a similarly sized monohull vessel.

The vessel takes into account the affects of a vessel’s motion on the crew’s ability to maintain concentration, and thus the proper control of the vessel. The vessel offers unique features that are designed to ensure superior seakeeping performance. For example, by minimizing the waterplane area of the vessel, Abeking & Rasmussen believes it has succeeded in minimizing the forces, which lead to sea response motion.

The yard contends that various stabilization systems have been developed to reduce rolling and pitching of existing vessels, but notes that all of these systems have their limits. As humans are not built specifically to deal with extended periods of the rigors of the sea, extended periods of motion at sea lead directly to lack of concentration, fatigue and seasickness, even in the most experienced sailors. In order to keep crew and passengers fairly comfortable and enable them to perform their main duties, the motion parameters of a vessel must be limited. Therefore limits have been defined, e.g. by the U.S. Navy or by ISO standards for the permanent accelerations on board of seagoing vessels, which represent the seakeeping capability.

Both vessels are sailing in a head sea of approx. 2m resp. 3m significant wave height.

The above-referenced 33-m monohull boat was designed for a top speed of 39 knots. However, to keep its movements within the Crew Limit of 4m/s², the maximum speed it can achieve is approximately 15 to 20 knots in seastate 4 to 5.

In comparison, the 25 m SWATH@A&R Pilot Tender can maintain its top speed of 20 knots, without even exceeding the limit for Crew Comfort of 2m/s², making it a faster vessel in rough seas.

The results noted are far from theoretical, as a pair of aluminium 25-m Pilot Tenders with a displacement of 12 5 tons have been in continuous operation since the summer of 1999, with a reported great success.

In addition, a 50-m SWATH Pilot Station Ship of the A&R design came into operation this August.

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