The elements that define the Hunt Deep-V give it the unique ability to navigate rough seas at higher speed with more safety and comfort than any other hull design. It is known for its soft, dry ride in all conditions, the ability to track straight with fingertip steering, stability at speed and at rest, and efficient running that minimizes fuel consumption.
These traits are valued by pleasure boaters, commercial and military users. In fact, the majority of pilot boats serving commercial ports in North America are Hunt designs. Here are boats – and people – who must go out in any weather, deliver pilots to ships quickly and safely, 24/7, all year long. For the same reasons, our Navy and Coast Guard also rely on Hunt Deep-Vs.
At Hunt Yachts, we believe running is believing. Take a test drive and compare Hunt to every other boat you’ve driven, you’ll find there’s no comparison.
Talking Hull design with Ray Hunt Design
How Hunt Yachts arrives at the legendary ride is the business of the naval architects at Ray Hunt Design. Here, they discuss the design elements of the newest generation of Hunt Deep-V hulls.
Hunt Deep-V Stability. Or How to Keep Everyone Happy Underway and At Rest.
Stability is a good place to start a discussion of hull design because it is key to the comfort and happiness of everyone on board. And it has changed over the years.
Stability at rest is largely dependent on vertical center of gravity and waterline beam. Early on, 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 and others of that vintage were light and fast for their time, but tended to roll in a beam sea. Today, we design each hull to have its chines in the water at rest for about half the waterline. This creates a wider beam on the water and the impressive stability of the Hunt Yachts’ hull.
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 resists rolling where a round edge doesn’t.
Let’s consider dynamic stability. The same forces that lift a planing boat above the water also stabilize the boat underway. Planing boats gain stability once on plane. They are actually stiffer running at speed. The Deep-V has added advantage, due to the deadrise, because the planing forces are always working to right the boat.
A Soft Ride- It’s All about the Deadrise.
Deadrise is the angle between horizontal and the hull bottom athwartships. The Hunt Ocean Series, for example, has a 20-degree deadrise angle at the transom. The angle increases gradually as you go forward to about 55-60 degrees at the bow. The more deadrise you have forward, the softer the ride. Many V hulls have constant deadrise carried the length of the boat. This makes for a hard ride. Variable deadrise that is flatter aft for stability and sharper forward makes for a softer ride.
A Dry Ride- Read the Chines, Lifting Strakes and Spray Rails.
Primarily their job is to shave water off the hull. A planing boat is trying to out run the ocean, leave it behind and climb on top, so we want to get the water off the hull quickly. Water attached to the hull means drag and pushing it aside makes waves. Both are wasted energy. A big bow wave may look dramatic but it takes a lot of HP to push water around like that, (and the top of that bow wave usually blows back in your face.) We want to snuff out bow waves. That is the job of the chines, lifting strakes and spray rails.
The primary chine is where the topsides meet the bottom; where the hull turns the corner. It defines the running surface. It runs bow to transom. We vary its size and location depending on several factors. We desgn lifting strakes forward on the bottom and run them aft at varying lengths. These peel the water off, reducing wetted surface, cutting skin friction (drag) and redirecting the water traveling up the hull to add a lifting component that in turn has two benefits: it helps lift the boat out of the water, and it adds stability. A survey of spray rails at a boat show will turn up every possible shape. Some are so small and round they do nothing. Others are under water all the time, and also do nothing. Some actually are indented into the hull. The water just passes these by. Hunt strakes are large and sharp to give the boat great control, dynamic stability, and a dry ride.
The Hunt Deep-V Is Patented, Perfected and Proven Over Time.
While it is still very similar to Ray’s original concept, Ray Hunt Design has improved the Hunt Deep-V and tailored it for every application from 10 ft. PWCs to 110 ft. motoryachts. If you look closely at hulls in a boat show or boatyard you can easily pick out a Hunt hull: more deadrise forward, finer waterlines, robust and sharp edged chines and strakes, and generous flare.
Many other hulls carry transom deadrise too far forward giving a harsher ride. Too sharp forward and the bow will dig in making for a wet ride, or worse. Others have soft chines and strakes that are far less effective in knocking down spray and holding the boat steady at sea.
Some boat designs let interior accommodations define hull shape above and below the waterline. Hunt Yachts put the ride first, so on the unpredictable ocean, you will be comfortable and confident and safer at all times, in all seas.
And At Slower Speeds…
Hunt Deep-Vs are well known as faster deigns. They also perform smartly at slower speeds. Here’s why. Deadrise is less important than other critical characteristics at slower speeds. Get the run and horizontal lines aft, the propeller/gear ratio, trim and weight right, and Deep-Vs make superb displacement boats. Hunt Yachts get those right and give you more hull and displacement under the water than flat-bottomed boats. They handle better, go straighter with less effort, and are more stable than traditional displacement hulls thanks to their hard chine. And when you need get up and go, it’s there for you.
The Joy of Trim Tabs.
All planing boats should have tabs, just like planes have flaps. Trim tabs or the newest device, the interceptor, allow you to adjust a boat’s trim to sea conditions. There is no one perfect trim angle for all conditions. Up wind you want to keep the bow down a bit to soften the ride into a chop. Downwind you want the bow up some to prevent digging in and broaching. We design our boats to run with a bow up attitude and use tabs to trim the bow down. A boat that naturally runs flat can’t get the bow up, which is ok if you never venture out beyond the breakwater. You can use trim tabs to correct for off balance loads, and to add lift so you can keep your boat on plane longer at lower speeds for greater fuel efficiency and range. In this mode the wake is flatter too.
Consider Fuel Efficiency.
First, think in miles per gallon, not gallons per hour. The latter means nothing until you factor in the distance traveled. In larger yachts ½ nmpg is quite decent mileage. On average if you can get 1 nmpg you are doing well, and 2 + nmpg is great. Check out some magazine seatrial data and it will surprise you. You will find some go-fast boats get better mileage than some slow trawlers. Typically, a planing boat will be most efficient once it is on plane, but as you go faster you will burn more and more fuel for smaller increases in speed. You can lower the planing threshold and thus improve efficiency by lowering the trim tabs (this adds lift). Electronically-controlled engines give you a fuel consumption read out so you can find the sweet spot.
Wedge Shaped Rudder: Ingredient of the Secret Sauce.
At high speed the flow around the rudder is separating from the surface; it goes turbulent and will not stay attached to an airfoil shape as it will on a slower speed vessel like a sailboat. So, we don’t want a low drag airfoil shape because the narrow trailing edge will be working in a void of turbulent water. The helmsman will experience a mushy feel in the wheel, and the boat won’t respond until he puts the helm hard over. The wedge shape fills in the void, so when the helm is turned, the wedge rudder immediately finds solid water to work against. Delicious responsiveness.
We hope you’ve enjoyed this design commentary. We know you’ll enjoy Hunt Yachts. Driving is believing. Arrange a sea trial.