Ocean-going powerboats tend to be of the trawler type: heavy displacement with deep hulls. But MJM Yachts founded by Bob Johnstone, who was the co-founder of J-Boats (which has a reported 12,000 sailboats still sailing worldwide), has recently built a 50-foot power boat called the 50z that has more of a lightweight planning hull than a displacement one. The 50z also has a Seakeeper Gyro Stabilizer unit as standard equipment. The Seakeeper unit spins at 8,000 rpm and counteracts the effects of roll. And the 50z, built by MJM licensee Boston Boatworks, is designed to be lightweight with pre-preg epoxy, Kevlar, E-glass and Corecell. The result is that the boat achieves a fuel efficiency of 0.9nm/pg at 25 knots — speed and efficient fuel consumption.
The previous boat in the line, the 40z is ISO Certified Category A Ocean. According to MJM, there are only two 40 footers with that certification, the 40z and the Nordhavn 40. The 50z is built to the same standards as the 40z.