January 28, 2023
By David Rearick
Simply put, the type of boat hull you buy is the critical piece to getting the performance you desire out of your duck boat. You wouldn’t buy a scooter to drive down the interstate so why would you buy a deep V-hull to hunt flooded timber or a flat bottom for big water? Whether you’re in the market for your first or next duck boat, here’s the bottom line on duck boat hulls.
DON'T MISS the author's "Guide to Buying a Duck Boat"!
The Basics of Duck Boat Bottoms
The simplest way to distinguish the different hull types from one another is to associate them with different hunting situations. When you think about a hull type, think about the water levels, obstacles, and potential hazards in the respective environments. To help illustrate this, I came up with a handy chart to connect the hull types to their best environments.
The good news is, as the illustration indicates, all hull types have some crossover, allowing them to be safely and effectively used in different conditions. This allows hunters to explore a diverse number of environments with one boat and eliminates having to build an extra garage just to store an armada. (Don’t let me discourage you from doing so, if that is what you are into, and don’t tell my wife I said this because we don’t need any more fall decorations in lieu of a new boat!)
Beyond the Visual
Now that you have a better visual understanding of the different hull types, let's dive into what makes them tick. There are three main and important features on any duck boat hull. The first is, as you'd expect, the degrees from plane that the hull rises to the sides. For a deep V-hull, that number is greater than 20, while for a flat bottom it is closer to 0. The second is the bottom width, which is the space between the slides that is generally flat. While some deep V-hulls have a bottom width, bottom width is of greater importance for flat and modified V-hulls. Finally, the third is hull chine, which is a feature engineered for performance in different environments.
Feature 1- Degrees of “V”
In duck hunting terms, the degrees of “V” is important for two reasons. A good way to illustrate these reasons relates to drag and displacement. If you put a piece of plywood on the water’s surface, you can spin it around easily, but without much control, it doesn’t track in a straight line when pushed. It also doesn’t sink below the surface, leading to drafting (or displacing) a minimal amount of water. (Draft is the amount of water depth required for the hull to rest at equilibrium). Now, if you were to take that same piece of wood, cut it in half, and then screw it back together at an angle, when you place the “V” in the water, you can steer it, but it requires more force to turn. Also, part of the wood is now below the surface of the water, as the wood is now drafting in inches, rather than millimeters. The biggest advantage of a deeper V is simply a softer ride; but the more water you need in which to run (draft; or how much boat is below water level).
If I haven’t lost you with my explanation yet, the first reason hunters need to understand the degrees of “V” is clear, the more V you have, the more draft you have. This amount of draft will impact your ability to safely navigate shallow water and over obstructions, especially at non-plane speeds. The second reason is control. The less “V”, the lower the ability to track at slow speeds. Envision a flat bottom boat floating on top of the water while the “V” hull displaces water with the “V” and allows it to steer/cut the water when under power. You should be able to understand that as the degrees of “V” increases, so does control.
Feature 2- Bottom Width
While bottom width (or the flat portion of the hull that contacts the water) is important for all boats including V-hulls, it is a specific option for most flat bottom and modified V-hulls. Bottom width creates lift and reduces draft. Going back to the plywood example, a 4x8-foot sheet will draft less than a piece of wood that is 2x4-foot with the same amount of wood placed on it. In boat terms, a boat’s hull puts pressure on the water’s surface that is counteracted by the tension of the water surface (what we also know as buoyancy). The more surface area, the greater amount of weight it can hold, but at the expense of creating more friction. You might ask why wouldn’t you want as wide of a bottom as possible? While that question is logical, extra bottom width creates extra friction and drag, slowing down the boat and increasing the power required to get the boat on plane. As an example, a 16-foot boat with a 42-inch bottom width gets on plane at 20 mph with a 15-hp outboard. That same 16-foot boat with a 60-inch bottom width may require a 25-hp motor to accomplish the same speed. The key here is to balance your outboard motor with the bottom width of a boat, while considering the amount of capacity you need to transport hunters and gear.
Feature 3- Hull Chine
The terms square, round, or tapered chine are often tossed around as descriptors when describing a particular boat’s hull design. While the type of chine is a critical component in a boat’s performance, for most boat owners, chine is not a well understood concept and is often overlooked when purchasing a duck boat. Using a very broad brush, chine is divided into four different classes essentially based on the number of folds or changes in direction of the panels in a boat’s hull. The changes in direction or folds are seen near the intersection of the vertical side panels and horizontal bottom of the boat’s hull.
For simple illustration purposes, a straight V-hull found on many large ocean vessels is a single-chine, a flat bottom boat is a two-chine hull, some modified and deep V-hulls are considered a three-chine hull, and a more complex hull design that often looks nearly round with multiple folds are considered multi-chine hulls. Beyond the number of folds, chine is broken down into either hard or soft, based on the smoothness or sharpness of the transition or folds in the hull. A good example of hard chine is a flat bottom boat that has a sharp, nearly 90-degree angle where the side panels and bottom of the boat join together. On the other hand, a soft chine is used on molded fiberglass boats where the transition between panels is done using of a smooth, gradual radius rather than a sharp transition.
While many duck boat manufacturers don't use the basic terms of hard or three-chine hulls when laying out the specifications for their boat, each manufacturer uses its own terminology. For example, a square chine would be considered a hard chine, a round chine would be considered a soft chine, and a tapered chine is one that consists of multiple gradual changes near the fold of the boat, a.k.a. the multi-chine. These different chine types and variations directly influence the performance and handling of the boat, making them an important feature of any hull. Luckily, boat manufacturers have spent countless hours designing their boats and equipping them with the chine that they feel best suits their hull design and covers the circumstances surrounding the intended use of the boat. While some features of a duck boat like the layout or floatation placement are driven by the boat's design, in most cases, a boat's design is directly driven by the type of chine the hull will incorporate.
What's Your Purpose?
One of the factors considered when deciding what type of chine a boat will incorporate is the boat's intended purpose. While the angle or sharpness of the hull's transition may sound trivial, it is actually the exact opposite. Hard chine boats are typically easier to get on plane, have added stability when sitting idle in rough water, and increased drag, but have the tendency to pound in rough water as they cut the water rather than slowly displace it. Soft chine hulls tend to run slower than hard chine hulls but make up for it in handling as they smoothly bank or glide into turns and provide a smoother more enjoyable ride with less pounding when the weather turns sour. Soft chine hulls also have the tendency to roll in the water, which could be either a positive or negative depending on the type of water being hunted and the presence of large waves. In the ocean, a soft chine hull like a TDB will roll with the waves instead of rocking sharply like a hard chine, helping it to stay upright if caught in a cross wave.
Why Safety is an Important Factor in your Decision
While you could make the logical case that a deep V-hull could be used on a mud flat with adequate depth or a flat bottom could be used in the ocean, safety is the deciding aspect. While a flat bottom boat can certainty, and have been, used on the Great Lakes and even the ocean, that doesn't mean that it is a brilliant idea. For starters, while on a perfectly flat clam day a flat bottom would glide right over the water, what happens when the weather unexpectedly picks up? If the wind and waves pick up, trying to get safely back to the launch in a flat bottom will, simply put, be a nightmare. The boat will get tossed and blow around, it will not be able to track safely, and the hull will slam into every wave, jarring both your tailbone and your demeanor. In order to get my point across, you have a much higher risk of death in flat bottom boat in 2-foot waves than you do in any boat with a V-hull.
On the flip side, the use of a deep V-hull in very shallow water, while not specifically life threatening, carries the risk of running aground, into rocks, or getting hung up on unforeseen obstacles. In most of these cases, provided you don't run aground and get thrown from the boat, you will survive. However, the risk of injury, significant damage and repair cost, and lack of ability to get to the hunting grounds are all reasons not to attempt it.
In summary, to select the most appropriate duck boat hull for the way you intend to hunt, start by defining your applications and needs and then select the type that covers the majority of your applications. While there is no singular hull type that can handle every scenario, now that you understand the basics of duck boat bottoms, your choice will go a long way to maximizing your return on your investment.