by Capt. Dave Lear

How do traditional Deep-V hull designs compare to their high-speed, stepped hull counterparts?

Aug 28, 2018 | Bluewater Perspective, Featured, Jupiter Boats, Magazine, News, Regulator Boats | 3 comments

Exceptional offshore fishing boats are not a fluke. They are the culmination of exact calculations, computer-assisted design and a well-executed manufacturing process. Each one is conceived to fill a niche in a product line because of size or style. They all share common design elements to ensure rough water performance, predictable handling and proper running attitudes. Naval architects and builders work hand in hand to achieve these desired traits.

“The hull design has to suit the purpose of the boat in terms of where and how it will be used and the speed expectations,” says naval architect Lou Codega, who designs the Regulator line, among others. “Outboard powered boats have to run fast in waves yet still get you home when it gets snotty. It’s a lot more complicated than simply choosing a look.”

Stepped hulls are great for top speed

Speed is not limited by design, but rather by how much discomfort the operator is willing to endure

Design of chines, strakes and center of gravity are paramount in great hull design practices

Codega incorporates an aggressive deadrise at the bow that transitions quickly aft to the transom. He defines deadrise as the angle the bottom makes starting at the center line relative to the water’s surface. Like a knife, a boat with a deep-V shape or larger deadrise cuts through waves easier but the sharper angle also tends to roll side to side if not compensated by adjusting the molded strakes and chines of the hull bottom.

Deep-V vs. Stepped Hulls

“Deadrise at the bow is more important than the transom because that’s what is doing the work,” he explains. “Strakes come into play by how quickly they taper while downward angles on the forward chines provide a drier, more stable ride. It’s all a trade-off. The characteristics that make a boat go fast hurt sea-keeping. Speed is not limited by design, but rather by how much discomfort the operator is willing to endure. When it gets rough, you’re glad to have a big, heavy boat to slog through seas versus getting tossed around.”

Codega does not add steps or notches to the outside chines in his designs because of performance considerations. Steps serve to ventilate the hull to reduce friction, but they are also prone to unexpected handling concerns if not designed properly. “Stepped hulls work best at high speeds,” he explains. “Smooth bottom hulls are more efficient at 30 to 35 knots, which is normal operating speeds for most sportfishing boats. Handling is also much more predictable with traditional hull designs with continuous chines versus those with steps.”

“The characteristics that make a boat go fast hurt sea-keeping.”

Lou Codega
Naval Architect behind every Regulator hull design

Stepped Hull Running

Easy Does It: Going airborne might get everyone’s blood pumping, but do you have control of the vessel?

Carolina Style

With their Edenton, North Carolina roots, Regulator Boats feature a pronounced Carolina bow flare, which Codega says adds style, a drier ride and keeps the bow from stuffing into waves when running the rough inlets common on the Eastern seaboard. Codega utilizes engine brackets extensively and avoids pocket transoms and notched steps in the outside chines.

“Engine brackets move the propellers away from the hull into cleaner, solid water like a notched transom,” he says. “In addition, they add more space to the cockpit, especially with the larger four-stroke outboards. Plus they let me adjust the center of gravity to where I want it. Another benefit is brackets provide more control flexibility with running and static trim.”

Albemarle Boats, also based in Edenton, builds six sport-fishing models, three with bracketed four-stroke outboard power and three larger sizes with inboard diesel propulsion. Burch Perry is the company’s long-time general manager.

“We are a traditional builder with deep-V hull designs, the recognized Carolina bow flare and solid glass bottoms. We believe in displacement for our size segment and our lamination schedules reflect that. Everything we build is an evolution, but there are an awful lot of similarities to what we started with 30 years ago,” Perry says. “Deep-V hulls tend to be tender on the drift or when trolling, so we add wider reverse chines to counter that effect. The chines help with the spray too, while the strakes provide lift and spray deflection by turning the water back downward.”

Perry says Albemarle listens to dealers and current owners for real world feedback when developing new models. Designs focus on a deep forefront deadrise that is reduced aft for a soft, predictable ride.

The Albemarle 27’s unique chine/spray rail

The center of gravity for each boat is also carefully measured. “We continue to play with and tweak our running angles, but the center of gravity is always paramount,” he says. “We don’t want any unexpected handling problems. The goal is for each boat to be efficient and perform well regardless of whether you have a full tank of fuel in the morning heading offshore or you are half-full coming back in. When you strike that balance, you have a real win.”

A Positive Advantage

Donald Blount and Associates design Jupiter Marine models, with considerable input from industry legend and company president Carl Herndon. The Palmetto, Florida-based builder produces nine models, including the latest introduction, the 43 Sportfish. With the exception of the 25-foot bay, all utilize the company’s signature Posi-Stern hull design. This flattened pad on the aft centerline keel has been a constant feature throughout Jupiter’s 30-year history.

“[The Hull Pad] provides dynamic lift, higher running speeds and increased fuel economy.”

Deep-V Hull Design Terms
(as seen on Jupiter 43)

“The Posi-Stern feature starts a little aft of the center of gravity and goes all the way to the stern. It provides dynamic lift, higher running speeds and increased fuel economy,” says Don Smith, Jupiter’s sales and marketing manager. “Because of this stern lift, the bow rise is approximately four degrees upon acceleration, so visibility from the helm is very good with a level running attitude.” Smith adds that nearly all models are built with a 60-degree bow entry with 24 degrees at the transom. None of Jupiter’s designs include chine steps. The bows are narrower in what is often referred to as the Florida style.

No Surprises: Jupiter’s hulls are designed to track straight with no wandering

“We haven’t seen the need for a pronounced bow flare,” Smith explains. “All of our models are based on the original 31, which we feel has sleek and timeless styling. We do make careful calculations when designing these boats, though. For example, if the center of gravity is too far aft, that leads to unnecessary bow rise. So we are very precise where the fuel tanks are located to maintain that weight balance and level attitude. The center of gravity is typically right around the helm seat.”

Smith says the beam dimensions of Jupiter models are adjusted according to length. Balance is another consideration to maintain consistency as far as cockpit size and console location. “Our hulls are designed so there are no surprises, no hard turns, no unexpected maneuvers,” Smith adds. “We want them to track straight and not wander. Operators should be at ease at the helm. From a construction and running standpoint, we design each hull for going offshore comfortably and efficiently.”

Hydrodynamics pertains to the forces in, or motions of, liquids. A well-executed hull design, regardless of brand, enables those forces to match briny liquids for a safe and comfortable return to the dock when those white-capped liquids build to six-footers and you’re 40 miles offshore.

Traditional Deep-V

  • Slower and less efficient than comparable  stepped hull designs.
  • Time-to-plane and bow rise during hole shot is more  pronounced than in stepped hulls.
  • Decades of proven performance and handling with many new refinements.
  • Less expensive than stepped counterparts.
  • A bunk or roll-on trailer can be used for transport. Bottom maintenance is easier with less surface area and crevices for bottom growth to occur.
  • Are more conventional designers playing it safe  with proven deep-V “smooth” hull forms?

Stepped Hulls

  • Provide greater speed and efficiency with the same horsepower rating of a comparable deep-V hulls.
  • On-plane sooner and exhibit less overall bow rise than traditional hulls. Minimal trim required through RPM range.
  • Early attempts plagued with poor handling characteristics, but newer designs are much improved.
  • Higher price premium due to complexities of glass layup and necessity for increased testing.
  • Trailering, lifts and launch become more complex to protect the steps from damage. Stepped hulls cannot use a roll-on trailer and have more crevices to keep clean.
  • Some builds aren’t stepped, just notched. Meticulous design of step placement and center of gravity is essential.