WAGENINGEN _ Because nothing ruins a day at sea like a generous roll, countless systems have been developed to neutralize that motion. Weights, hull appendages, gyroscopes, tanks, bilge keels, paravanes, flopper-stoppers, fins, cylinders. The list goes on.
The Maritime Research Institute of the Netherlands has been rethinking ways to tame the roll motion at anchor. In a ground-breaking project with Edwin van der Mark Naval Concept Design, it has come up with a superyacht-submarine crossover.
Conventional damping systems ignore a hull’s hydrodynamic properties, i.e. its behavior in water. So the MARIN project does not pursue new damping techniques, but better seakeeping by partially submersing a superyacht and playing with the hull form to reduce motion at anchor.
Setting a hull deeper in the water and creating flood recesses and openings will reduce the waterline area and thus the excitation of waves on the hull. Changing the way the yacht “floats” in this manner creates what MARIN calls a “comfort draft,” turning a yacht into a deluxe submarine.
That ‘comfort draft’ term is a nod to John Venables of Naiad Dynamics which has made more than 10,000 stabilization systems. He speaks of a “Comfort Imperative,” meaning: no onboard comfort, no clients.
Motion damping gear is as old as the sea. But not until recently did a Dutch-made system enter the market that stabilizes a yacht underway, at anchor or when drifting. Lying idle _ anchored or moored _ is superyachts’ natural habitat. Dutch custom maker Feadship, using historical AIS data of 35 Feadships, found a few years ago that “generally, each yacht sails approximately 10% of the time.”
MARIN’s comfort draft concept is designed to stimulate thinking. For now, it focuses on the hull design, stability requirement and hydrodynamic properties but not the immersion mechanism. That’s the job of you naval architects and engineers out there.