(70 x 3.28) = feet per second (70 x 3.28) ÷ 6,080 = nm per second ((70 x 3.28) ÷ 6,080) x 60 = nm per minute ((70 x 3.28) ÷ 6,080) x 60 x 60 = nm per hour (kts) = 135.95 kts