Turning at a constant speed of 1500 RPM or twice the speed of earlier submarine diesels, these light weight aluminum engines had a history of frequent breakdowns. Albacore's two engines were the last ones of this type in active service. These engines, installed in an entire class of six submarines, were removed and replaced because of their unreliability. Those 24 dismantled engines and their repair parts were warehoused and used to keep Albacore's engines operational. One of the considerations for retiring Albacore was the cost to the Navy of either buying and installing new engines or starting up a long dormant production line to make additional repair parts since she had nearly used up all the parts taken from the other submarines.