R--T-AFT SSDG Replacement Installation Work Package Development

The Engineering Branch (N72) of the Military Sealift Command (MSC) Technical Division requires technical support to develop an American Bureau of Shipping (ABS) Approved Ship Service Diesel Generator (SSDG) replacement, or "repower," and electrical system modification work package to be used on the four MSC Fleet Ocean Tugs (T-ATF Class), USNS CATAWBA, USNS NAVAJO, USNS SIOUX, and USNS APACHE. This task provides requirements for professional engineering services to develop ABS approved removal and installation drawings, a shipyard work item, and cost estimate. Each of the four ships is approaching 30 years old and still have the original three SSDGs manufactured by Detroit Diesel. The manufacturer no longer supports the generator sets, which is causing a lack of available parts and long lead times. The age of the SSDGs alone make them obsolete and they require constant maintenance. New diesel generator sets have the potential to be more fuel efficient, smaller, lighter, and compliant with Environmental Protection Agency (EPA) emission regulations. The existing generators are rated at 450 volts, 60Hz, 3 phase, 400kW, and 0.8 pf. SSDG No. 1 is electric start and No. 2 and No. 3 are air start. The existing generators onboard are capable of being paralleled but must be manually adjusted for load sharing. The controls are antiquated and cumbersome for daily operations. Generators can only be paralleled manually and locally at the ship service switchboard. This is only done when the ship's loads are transferred from the on-line SSDG to another SSDG. All load sharing must be manually accomplished. The generators do not have the capability of paralleling with shore power (utility) and, therefore, the ship must drop all load prior to connecting to a land-based grid. Ships do not have the capability for automatic call up of a standby generator, auto paralleling, or auto placing a standby generator online. This replacement work package offers the ability to design in more modern operating features. SSDG No. 1 is located in the lower level pump room forward of engine room and is electrically started. SSDG No. 2 and 3 are located in the engine room and are both air started. MSC is currently participating in an on-going procurement of new SSDGs and equipment to replace the existing three SSDGs on each of the four ships. It is expected MSC will select a replacement SSDG and equipment which will be installed by the work package developed in this task. The work package developed under this task will install additional features such as automatic and remote paralleling between the three SSDGs, load sharing, and shore power upgrades.