365 June 2006

The McCalls: DP2 and Drilling Mud

Joe McCall, project manager for Seacor Marine.

When Rita came ashore near Cameron Louisiana she pretty much destroyed the town including Seacor Marine's project manager Joe McCall's house. “We thought that it would come ashore over in Texas,” recalled Joe, “So we had sent a bunch of the crewboats up into Lake Charles for shelter. But it came right down on them. They were all rafted up and came through it pretty well. The crews tend to be all up and alert for an event like that.”

Like the Seacor crews in a hurricane Joe McCall is alert full time to trends and directions in the Gulf of Mexico crew boat market. His latest new build at Gulf Craft in Patterson Louisiana is typical of the annual advances that Joe and his dad Norman McCall seem to develop on a regular basis working with the design team at Gulfcraft headed up by Grant Pecoraro.

“Over the years we have worked with Gulf Craft to stay up to date with our customer's requirements,” Joe explained recently. He then went on to describe their latest innovation.

The 190 by 35-foot hull for the new boat had been turned right side up and was being completed in the water for a December 2006 delivery. As usual the specifications are driven by customer demand. Rather than the usual set of water and fuel tankage this boat will carry liquid drilling mud as well. In the past this has been carried in the displacement hulls of offshore supply vessels (OSVs). The new high-speed boat will not replace these OSVs, but it will be used to “top-up” supplies or to provide specialized drilling mud. With a KTA50 M2 engines each rated for 1800 hp at 1900 RPM for a total output of 9000 hp. With five 54x54-inch propellers and three independent rudders redundancy is assured. The rudders are located behind the two outboard and the center engines. Should one of the outboard engines with a rudder fail there would still be two ruddered engines for maneuvering. Similarly the boat has three bow thrusters --- two tunnel and one azimuthing. Having two tunnel thrusters maintains power requirements while keeping the diameter small enough at 30 inches so that the thrusters will not come out of the water when maneuvering in ten-foot seas. The boat will have four Cummins QSM11 engines, two powering 290 kW generator sets that will provide power for the ship and power for the mud, fuel and rig water discharge pumps. The remaining two QSM11s will drive hydraulic pumps to provide power to the Thrustmaster Bowthrusters. With one of these two dedicated to the 400-hp azimuthing thruster and the other to the twin 200-hp tunnel thrusters.

With redundancy assured the need for efficient maneuvering under the rigs is aided by Seacor's continued use of controllable speed propeller (CSP) technology from CSP Electronics L.L.C. This system, capacity for 1100 barrels in six tanks each approximately 12 feet square the new boat will make 20 knots with a maximum load and 26 knots running light.

GA for the new boat.

This boat differs from Seacor's earlier drilling mud capable crew boats as those utilized deck tanks to carry only the dry powder for making mud. The liquid mud is considered an environmentally hazardous material. This drives the requirement for the new boat to be dynamic positioning two (DP2) equipped. To achieve a DP2 rating all propulsion and maneuvering components must be redundant.

For main propulsion the boat has five KTA50 M2 engines each rated for 1800 hp at 1900 RPM for a total output of 9000 hp. With five 54x54-inch propellers and three independent rudders redundancy is assured. The rudders are located behind the two outboard and the center engines. Should one of the outboard engines with a rudder fail there would still be two ruddered engines for maneuvering. Similarly the boat has three bow thrusters --- two tunnel and one azimuthing. Having two tunnel thrusters maintains power requirements while keeping the diameter small enough at 30 inches so that the thrusters will not come out of the water when maneuvering in ten-foot seas. The boat will have four Cummins QSM11 engines, two powering 290 kW generator sets that will provide power for the ship and power for the mud, fuel and rig water discharge pumps. The remaining two QSM11s will drive hydraulic pumps to provide power to the Thrustmaster Bowthrusters. With one of these two dedicated to the 400-hp azimuthing thruster and the other to the twin 200-hp tunnel thrusters.

With redundancy assured the need for efficient maneuvering under the rigs is aided by Seacor's continued use of controllable speed propeller (CSP) technology from CSP Electronics L.L.C. This system, developed in conjunction with Cummins, CSP and Seacor, allows the props to turn at virtually any low RPM desired. While the Cummins KTA50s idle at about 650 RPM the slowest prop RPM possible with the 2.9:1 reduction on the five Twin Disc MG-6858 gears would be about 200 RPM, the technology in the CSP system allows the prop rotations to be slowed below that while the main engines maintain their efficient idle rate which reduces fuel consumption. All of this is tied in to the DP system so functions with minimal input from the vessel operator. A computer calculates thrust on each prop and to adjusts maintain less than 50% load on any one to keep to DP2 requirements.  In addition to controlling propeller speeds the computerized CSP system provides an integrated alarm system that feeds predetermined alarms directly to the company's shore based offices as well as the boat's wheelhouse. Joe McCall explained that this system is well proven having been installed in five Seacor boats to date.

Most drilling mud weighs about 16.5 pounds per gallon but some mixes can weigh as much as 23 pounds per gallon. With 42 gallons per barrel and 1100 barrels this is a lot of weight and a large part of McCalls reasoning in adding a fifth engine on this boat. While the additional engine adds five knots to the vessel's speed it also contributes significantly to engine life as it allows each engine is working less. In addition to the liquid mud the new boat will have capacity for 430 long tons of deck cargo, 24880 gallons of rig water and 38650 gallons of fuel. Although the market isn't currently demanding it, the mud tanks could also carry fuel. The under 200 ton, Subchapter L classed boat will have seating for up to 36 offshore workers.

“This boat is designed to meet specialized needs,” McCall explained, “We will be supplementing the larger OSVs for topping up requirements or delivering specialized fluids.”

When developments are designed to meet new or emerging markets in the crew boat world they are likely to be built at Gulf Craft for Seacor and under the watchful eye of Joe McCall. While other companies are preparing vessels to transport liquid mud as well, the tradition of leadership that the McCalls have long delivered to Seacor remains.

For further information please contact:

Joe McCall
Project Manager
Seacor Marine
Cameron Louisiana
Phone: 337-775-5485
Mobile: 985-397-2314
E-mail: JMcCall@ckor.com

Red Cunningham
Marine Territory Sales Manager
Cummins Mid-South
Hwy. 90 East
Amelia, LA 70340
U.S.A.
Phone: 985-631-0576
E-mail: David.S.Cunningham@Cummins.com

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