More Horsepower, More Business
"You can never have too much horsepower in a crewboat," said Shane Pescay of Crewboats Inc., Chalmette, La. This belief, coupled with an increase in offshore drilling opportunities in the Gulf of Mexico, drove Crewboats Inc.'s decision to power each of its four new quad-screw crewboats with 3,300 bhp engines — ample power and speed for the vessel's demanding tasks.
Crewboats Inc. rents its boats to major commercial and independent oil companies to haul cargo and personnel to offshore drill rigs and platforms in the Gulf of Mexico.
Throughout the 1980s oil demand in the Gulf of Mexico was low while drilling occurred within 50 miles of the coast. As a result, offshore crewboats were built appropriately in the 100 to 120 ft. (31 to 37 m) range with cargo capacities of approximately 90 tons. In the early 1990s oil demand increased and oil companies began demanding larger crewboats to haul twice as much cargo and personnel to and from offshore platforms. At the same time, rigs were now being situated as far as 100 miles offshore, so maintaining high speeds became just as essential as their increased capacities. Beginning in 1989, Crewboats Inc. responded to the trend by building 11, 135-ft. (42-m) boats capable of carrying 190 tons of cargo and five, 152-ft. (46-m) boats that are capable of each carrying 235 tons of cargo. Most recently, the company has built Canyon Runner, Samuel P., Gulf Runner III and Anna P.
Mr. Pescay realized that keeping up with the offshore drilling trends meant more than building bigger boats. It also meant equipping them with power plants that could reliably deliver the horsepower needed to maintain a competitive advantage.
"Oil companies demand crewboat service 24 hours a day," Mr. Pescay said. "They don't put up with unreliable vessels, or those with downtime beyond routine maintenance.
Cargo is unloaded via a crane on the rig platform. During the process the boat must be as still as possible. Additionally, the crewboat cannot be tied to the dock or left idling while unloading, as wind and currents can cause the boat to drift into the platform, damaging itself and the platform. The captain steadies the vessel by a process known as 'walking the boat'. To do so, two engines are used to advance forward, while at the same time two are used to reverse with appropriate rudder power, to eliminate any fore or aft motion. "This process requires an enormous amount of power, especially when we're battling high winds, waves and currents," Mr. Pescay said. Another power option for crewboats is to install twin engines with a bow thruster, but, according to Mr. Pescay, a quadscrew design is more efficient.
"It's much easier to walk a boat with four engines. When done with two engines you run the risk of the boat pivoting left or right. Also, if you're out at sea and one of the engines breaks down, you can return to shore faster with three engines than with one." Mr.
Pescay adds that a quad-screw vessel is more cost effective on a price-per-horsepower basis, when compared to two high horsepower engines and a bow thruster.
Mr. Pescay specified four Caterpillar 3412 engines from Louisiana Power systems, Belle Chasse, La, for each new vessel. Each engine is rated 825 bhp @ 2,100 rpm and powers a Twin Disc MG 5202 marine gear with a 2:48:1 ratio turning a four blade, Nibrol 42 in. by 38 in. HyTorq propeller. Each boat has a fuel capacity of 10,000 gallons. This fuel and capacity can be used to either pump to the rigs or refuel the oats.
Lasting Power Mr. Pescay reported that the on-demand horsepower during cargo unloading has been very good with all the boats, even during rough weather or while unloading pipe, which can take several hours. All of the vessels maintain high speeds when load- "ng and unloading. Each 135-ft. 5-m) vessel is capable of hauling pproximately 190 tons at 20-21 nots and can reach a maximum peed of 26 knots unloaded. "There is at least one time I can ecall when we won a major bid rom an oil company because we ffered the highest capacities at he highest speeds - not just ecause of the price," Mr. Pescay aid. For the same job, competiors only offered approximately 90 ons at 14-18 knots. Crewboats nc. still has a contract with the ompany today.
As the oil trend continues, rewboats Inc. is continuing to uild seven, 152-ft. (50-m) boats, hich will bring its fleet to 36 vesls 14 large offshore vessels and small crewboats.