All boat hulls have their own strengths and weaknesses, but if you were trying to identify the best boat hull design ever, the SVVT is certainly one that would be in the running. SVVT stands for Stepped Vee Ventilated Tunnel, and it was created by Michael Peters Yacht Design of Sarasota, Florida. It is actually the latest hull design by Peters, in which the air is directed into a tunnel behind the steps, helping to improve fuel efficiency, overall handling and provide a softer ride for those onboard.
Above: A 2021 Caymas 341 CC center console boat with an SVVT hull design by Michael Peters. Photo via North Point Yacht Sales in Annapolis.
The Science Behind SVVT
The concept behind stepped hulls dates back almost as far as planning hulls, and the basic idea has always been the same: by designing in a longitudinal notch in the hull bottom and chines, wetted surface and thus friction can be reduced. As the boat moves forward, low pressure is created just aft of the step. This creates suction at the notches in the hull sides, drawing in air. Then as speed increases and more and more lift is produced, the section of the hull just aft of the step pulls in more and more air until there’s a whole pocket of surface area that’s no longer in contact with the water.
The net result should be increased speed and efficiency, and in most cases, it is. However, steps can have a lot of very undesirable side effects. In the most extreme cases handling can become dangerously unpredictable, as large surface areas of the hull aren’t supported by the water. In some other cases the steps create so much aeration of the water passing under the boat that the engine’s raw water intakes don’t get sufficient water flow, and the cooling systems malfunction.
Some boatbuilders put a lot of time, effort, and research and development into stepped hulls over the past couple of decades, and the designs found on the market today are generally quite reliable. Still, as a result of these issues and the amount of work it can take to overcome them, stepped hulls remain less common than straightforward deep-V hulls.
By all accounts, the SVVT design appears to not only eliminate the common problems seen with stepped boats, but also enhance the advantages. First off, it has two steps rather than one. While this isn’t unheard-of, what the hull looks like aft of the steps, the “VT” or ventilated tunnel part, certainly is. Essentially, a centered tunnel runs aft with vertical sidewalls. As air is channeled down the tunnel even more wetted area is reduced, while the sidewalls dig in and grip the water when a turn is initiated. Net result? The hull is stabilized and exhibits none of the unpredictable handling some other stepped hulls can produce, while delivering clean water to the props and powerplants.
2021 Caymas 341 CC with an SVVT hull design. Image credit: Caymas Boats
Advantages of the SVVT Hull Design
Steps are intended to boost speed and efficiency and the SVVT without question delivers both. Just how much is a point of debate, but in truth there’s no specific set number because it can vary depending on a particular boat’s size and weight, its load, and the sea conditions it’s running through. That said, a 15-percent increase in speed and efficiency is the most commonly used reference point. That might not sound like a huge number, but consider a boat that tops out at 45-mph while burning 20 gph. With the SVVT incorporated into the hull design, that could become a 51.75-mph boat without burning a single drop of additional fuel.
On top of that, there are advantages that go beyond speed and efficiency that (having sea trialed a dozen or so boats equipped with the SVVT in varying conditions) we can attest to. First, models with the SVVT hull tend to rise onto plane with little to no bow rise, and even running a 40-plus-foot boat, the captain never loses sight of the horizon over the bow. Second, having that air under the boat forms a cushion of sorts, softening the blows as the hull comes down on waves. The feel is somewhat like being on a powercat, and though it’s less pronounced, you can still sense it underfoot when running through rough seas.
Boats With SVVT Hulls
Perhaps the best proof of the SVVT’s value is the fact that it’s been adopted by multiple boatbuilders, including several in the top tier. Caymas Boats, the new company started by National Marine Manufacturer’s Association Hall-of-Famer Earl Bentz, utilizes the design. The Valhalla line of boats recently introduced by Viking Yachts does as well. Invincible Boats monohull designs run on the SVVT, too. Mag Bay Yachts, Barker Boatworks, Blacktip Boatworks, and Gulf Stream Yachts all employ it as well.
Most impressive, however, is that even the United States Navy has seen the superiority of the SVVT hull design. The Vigor Fast Interceptor, a 68-foot multiple-mission vessel designed to perform at up to 70 knots, rides on a SVVT. The Metal Shark 52 Fearless Super Interceptor, which is also designed to run at speeds up to 70 knots, utilizes an SVVT hull design as well and 15 are currently under construction for military and law enforcement organizations. In fact, all of Metal Shark’s Fearless range (six models ranging from 32 to 52 feet) which are currently in use by military and law enforcement agencies bear the SVVT bottom.
The Best Boat Hull Design
So, is the SVVT truly the best boat hull ever designed? That’s a loaded question. In fact, no one hull design could ever be “best,” because different boats are designed to do different things. The SVVT would not, for example, be a very good hull for a trawler or an aft cabin cruiser, much less a sailboat. But if you’re talking about a planing powerboat that’s intended to operate at fast speeds through the open ocean, there’s no doubt that the SVVT is going to prove tough to beat.