Tough New RIB with Hunt Yacht Qualities

At-rest or static stability, is largely dependent on vertical center of gravity and waterline beam. Early deep-vs were designed to float with their chines clear of the water for speed, so they were narrow at the waterline, skinny, for more speed.  The Bertram-31 boats and others of that vintage were light and fast for their time but did roll from chine to chine when at rest in a beam sea.  Today we address that problem by designing each hull to have its chine in the water at rest for about half of its waterline.   This creates a wider beam on the water and and a stable boat.  Today’s deep-vs do not roll any more than flatter bottoms of the same beam.

It’s also important to understand that hard chine boats are generally more stable than round bilged boats. This is because the hard edge of the chine is more resistant to rolling than a nice soft round edge.  A hard chined boat equal in waterline beam to a round bilged boat will be stiffer.

Static stability is only part of the picture however.  Another component in planing boats is dynamic stability. And it is an important one.  The same forces that lift a planing boat above the water also stabilize the boat and counteract rolling.  Displacement boats have no such benefit, thus the need for fin stabilizers and flopper stoppers.  Planing boats gain stability once on plane. They actually are stiffer running at speed. The deep-v has the added advantage due to the deadrise because the planing forces are always working to right the boat. These forces are acting normal to the surface of the hull through the center of lift.  On flat bottomed hulls these forces are acting normal to the bottom also, but do not counteract a roll.

Hunt Yachts President, Peter Van Lancker, and C. Raymond Hunt Owner, John Deknatel discuss the rich history and great performance of the Hunt hull

Fraternal Twins

 

A great time was had by all and we met many new Hunt fans at the Newport International Boat Show and Norwalk Boat Show.

Second in a series of articles about the Deep-V Hull

What is a Deep–V Planing Hull ?

• It is a hard chine hull form that maintains a fairly constant deadrise angle aft

• Deadrise is at least 18- 20 degrees, and as much as 24 degrees aft.

• Buttocks are generally straight aft.

• Most have strakes, or lift strips on the bottom.

• Most planing hulls on the market today are decendants of Ray’s original concept. Offshore raceboats, 40 years later are remarkably similar to the original!

How does a Deep-V work and why are they so good in rough water?

• Sharp entry forward keeps pounding to a minimum.

• Shallow forefoot resists bow steering and broaching.

• V- shape aft gives evenly distributed displacement and lateral plane

• Hull tends to go straight in all seas with moderate steering effort.

• High chine forward along with multiple spray strips knock down bow wave and spray, reduce wetted surface, cut drag and add lift.

• Result is more speed and/or economy and a dry ride.

• Flare in topsides deflects any spray getting by the chine and encloses substantial reserve bouyancy making it nearly impossible to bury the bow.

• Deep-V has more depth than flatter bottomed planing boats and acts more like a displacement hull when at rest.

• As it rolls displacement increases and resists the roll.

• At speed the hull gains stability from the lift forces acting on it.

• The Deep-V leans into a turn – not out.

• None of the above matters if the water is flat!