Choosing a Boat Hull Type
Prospective boat buyers often concentrate on the length and width, and the cockpit and console layout, but tend to overlook the importance of the boat's hull type.
When shopping for a boat, the first question the boat buyer should ask him or herself is “which type of boat hull will be best for me?” After all, the hull determines how well the boat handles and performs; how comfortably it rides; and what waters it’ll be best suited for.
Boat Hull Deadrise
Before choosing a hull type, it’s important to understand deadrise: the angle in degrees between a horizontal plane and the bottom of the hull.
The more deadrise a boat has, the greater the angle between the hull and the horizontal plane, and thus the deeper the V-shape of the hull when viewed in section. The deadrise angle typically determines the hull type as follows:
- Deep-V hull: 20 degrees deadrise and above
- Mod-V hull:10-20 degrees deadrise
- Flat-bottom hull: 10 degrees deadrise and below
Deep-V Hull Type
The deep-V hull has a lot of deadrise, and the resulting sharp profile cuts through chop and waves instead of slamming into them.
As a result, deep-V hulls provide better tracking and a smoother ride in rougher waters. Deep-V hulls are the best for offshore use or rougher waters. The drawbacks to a deep-V hull are the added draft (the depth the hull reaches below the waterline) and reduced stability at slow speeds. The deeper draft generates drag, so boats with a deep-V hull usually need more powerful outboard motors to reach top speed. A deeper draft also makes deep-V hulls less suitable for shallow waters.
Flat-Bottom Hull Type
Flat-bottom hulls are rarely completely flat, but the minimal deadrise provides a particularly stable platform with very little roll in calm waters.
A flat-bottom hull also has a shallow draft, so the boat can navigate shallow waters of 10-inches or less. This makes flat-bottom hulls perfect for calm inland waters such as rivers and small lakes. Their stability at low speeds makes flat-bottom hulls ideal for trolling. The downside to flat-bottom hulls is their inability to channel water away from the hull, which results in “slamming” in even mildly choppy waters.
Mod-V Hull Type
The mod-V hull combines the positive elements of the deep-V and the flat-bottom hulls.
A mod-V design has a steeper deadrise at the bow that modifies to a lower deadrise toward the stern. The deeper V of the stern cuts through any chop, while the flatter bottom throughout the rearward portion of the hull provides stability. The result is a hull capable of running comfortably in rougher water while offering a stable platform at lower speeds. The reduced draft toward the stern also enables a mod-V hull to traverse shallow waters. Due to their versatility, mod-V hulls are common among family and recreational boats. However, these hulls aren’t quite as effective as deep-V hulls in offshore waters, or flat-bottom hulls in flat waters.
Which Hull Type is Best For You
If you know you’ll be running almost exclusively offshore and at speed, then a deep-V hull is probably the way to go.
However, if you’ll be using your boat predominantly on shallow inland waters, the flat-bottom hull may be your best option. If you prefer a boat that’s at home on a lake or a couple of miles out to sea, then the mod-V hull is the way to go.