Duramax® Marine - our marine bearings, sealing systems, coolers and fenders are known worldwide for their dependable performance. Duramax?Marine: the worlds choice for technologically-advanced, high-performance John......Duramax® Marine - our marine bearings, sealing systems, coolers and fenders are known worldwide for their dependable performance. Duramax?Marine: the worlds choice for technologically-advanced, high-performance Johnson, Cutless? Romor?brand marine and industrial bearings, stuffing boxes, shaft seals, keel coolers and fendering systems. At Duramax Marine, our commitment to excellence is evident in every product we manufacture. Our marine bearings, sealing systems, coolers and fenders are known worldwide for their dependable performance.