Did you know the engines in these ships until recently were Napier Deltic engines: An opposed 2-stroke Diesel engine designed in the 40s originally for locomotives. The engines were so unreliable in the minesweepers that for years the Navy use to limp around on one shaft so there was always redundancy. The engines had a 500 hr service interval but rarely made it 🙄. Thankfully, the engines have all been updated to modern inline Diesel engines.,(reply>), My last ship was powered by opposed piston engines, nothing unreliable about the design.