A Beginners Guide to Motorboats
There are many different types of motorboats, from small runabouts to mega yachts, with a vast array of hull shapes, construction materials, and propulsion systems. Sometimes referred to as powerboats, motor yachts, or superyachts (typically when over 100 feet long), what these boats share in common is that they all have some sort of engine or motor for propulsion, instead of harnessing the wind like a sailboat. We’ll give you the details on everything you need to know about different motorboat types, hull shapes, construction and, well, just about everything needed to be able to speak powerboat fluently. Next thing you know, you’ll be bandying about terms such as deadrise and vacuum-bagging.
The Powerboat Basics
Powerboats come in all shapes and sizes. The smallest recreational powerboats are craft such as rigid-hulled or inflatable dinghies and personal watercraft, while the largest recreational power craft include large motor yachts and even mega yachts. But before we get buried in the ins and outs of powerboat types, let’s take a look at the basic pieces and parts that make up most any power-driven craft.
All powerboats have a bow (the front) and a stern (the back). All have hulls (the bottom of the boat) and all have a topsides (everything from the hull up). Beyond these basics, all boats have a huge number of pieces and parts that have their own nautical names. You can learn them all, by reading our Beginner’s Guide to Boat Terminology.
Different Powerboat Hull Shapes
The ultimate end use of a boat will decide how its hull is designed and shaped. For example, offshore fishing boats generally need hulls with a deep-vee shape to help contend with choppy seas, while a deck boat engineered for use on lakes and rivers might have a modified vee with less angle in the hull. Other powerboats, such as trawlers and tugs, usually have more rounded hull shapes. Watch Boat Hull Basics to get a visual explanation of the many different powerboat hull types.
In the most basic forms, there are three hull types you’ll see out on the water:
- Displacement Hull: A displacement hull is one in which the amount of water the hull displaces does not change significantly as speed increases. In other words, the hull never really gets up on top of the water. Rather, it rides in it, pushing large volumes of water out of its way. The advantages of displacement hulls are that they tend to be very fuel efficient at low speeds and can be powered by smaller engines for a given length. The downside is that they’re typically much slower than other hull types. Trawlers, tugs, Downeast, and other passage-making powerboats are often built on displacement hulls.
- Semi-Displacement Hull: A semi-displacement hull is one that is designed to allow it to partially escape the confines of the water. In other words, instead of riding completely in the water as a displacement hull does, a semi-displacement hull can ride partially on top of the water at higher speeds. While more horsepower and fuel are usually required to drive a semi-displacement hull, it can travel at higher speeds than a purely displacement hull. Larger powerboats such as motor yachts, cabin cruisers, trawlers, and tugs powerboats often have semi-displacement hulls.
- Planing Hull: A planing hull is designed to break free of the water, riding mostly on top of it at high speeds. A planing hull transitions from acting like a displacement hull at low speeds to planing as it climbs up on top of the water. Planing hulls require more horsepower for a given length to reach top speed, but are also generally able to reach much higher speeds than other hulls types. Most recreational motorboats are built on planing hulls, including watersports boats, fishing boats, performance boats, and more. Some planing hulls have steps in the hull—engineered indentations—to increase planing and top speed performance. Get the details on hull steps by watching Stepped Hulls.
Breaking it down beyond these three basic categories, there are many different hull shapes you’ll find in today’s modern powerboats.
Catamaran (Multi) Hulls: These powerboats feature two separate hulls, connected by a deck. They provide an exceptionally smooth ride, reducing impacts even when compared to most deep-vee hulls, as well as excellent static stability and tons of deck space. A couple of downsides to catamaran powerboat hulls are that turning performance is generally not as good as monohulls, and not everyone finds the aesthetics of a catamaran powerboat pleasing. Though rare, there are some trimaran powerboats out there. These boats utilize three separate running surfaces.
Cathedral Hulls: Though cathedral-hulled boats are a relative rarity these days, you can still find them on the used market. These hulls have twin outboard appendages outside a vee-type main hull with open spaces between. This hull type planes very easily and is quite stable, though the greater exposed area at the bow can produce banging in choppy conditions.
Deep-Vee Hulls: Deep-vee boats are known for their ability to slice through rough seas, and they do it better than the majority of other hull forms. But deep-vee boats can have a tendency to roll quite a bit in a beam sea, as well as wallowing in turns.
Flat Bottom Hulls: Flat-bottomed boats like bateaus or Jon boats are typically designed for inshore waters and protected lakes and rivers. While the flat bottom provides more stability and has a shallower draft than most traditional vee-shaped or modified-vee hulls, this hull shape can produce an uncomfortable ride with lots of banging in rough conditions.
Semi-Vee Hulls: Semi-vee hulls generally have a sharp, vee-shaped entry at the bow with a transition to a flatter profile aft. These hulls are a bit more stable their deep-vee relatives, thanks to their flatter aft sections, but they are usually not as capable in rough conditions.
Pontoons: A pontoon boat hull is made with a deck platform mounted on two or more aluminum tubes that are pointed at their forward ends to cut through the water more efficiently. Pontoon-type hulls are among the most stable—especially triple-tube “tri-toon” pontoon hulls—but they are limited in their rough-water abilities.
Rounded Hulls: Rounded powerboat hulls are typically found in trawler and tug-type cruising boats, as well as other displacement cruisers such as Downeast and lobster yachts. Though these hulls can have a tendency to roll, they are extremely efficient, making them great for passage-making vessels. Some rounded hulls have an integral keel to improve stability and tracking.
For a more in-depth look at some of the most popular hull designs, read What Hull Shape is Best?
Motorboat Construction Techniques
Most modern recreational powerboats are constructed of fiber-reinforced plastic, also known generically as “fiberglass” or “FRP,” though boats such as bass, multispecies, jon boats, and pontoon boats are often built using aluminum. Larger boats, such as big motor yachts and megayachts, are typically built using either fiberglass, aluminum, or steel. Since most of the powerboats you encounter will be made of fiberglass, let’s take a look at the essentials of fiberglass boat construction.
Fiberglass boats are typically built using a precise female mold—essentially a negative of the hull, deck, or component shape. In that mold first goes a thick layer of gelcoat—a colored, high-quality, glossy resin. Next, workers start applying various layers of fiberglass cloth inside the mold, which is then thoroughly saturated with catalyzed epoxy, polyester, or vinylester resin.
Sometimes a reinforcing grid is added to strengthen the hull. Other times, a vacuum is applied to the mold to remove any excess resin. This generally makes a stronger, lighter hull. The process is called vacuum-bagging and you can find out more about it by watching our Boating Tips: Understanding Vacuum Bagging video. Once the resin has cured, the new hull is pulled from the mold. The deck and any other components, such as consoles and seating fixtures, are built the same way. Though the process can be much more complex, this is fiberglass boatbuilding in a nutshell.
Fiberglass is super-strong, but must be laid up in multiple layers to be most effective. This, unfortunately, adds a lot of weight, which can affect a powerboat’s performance. To solve this problem, builders often sandwich a core material made of balsa or foam between two layers of fiberglass. This makes the hull, deck, or other component stronger, but also lighter in weight than using just fiberglass. If you want to better understand how cored hulls are built and work, our Understanding Foam Core Boat Construction video is worth a look.
The Power Behind the Powerboat
Powerboats are typically fitted with one of five different types of propulsion systems: inboard, inboard/outboard (also known as stern drive), pod drive, jet drive, or outboard. Let’s take a look these different systems and their components.
- Straight Inboard: A “straight” inboard propulsion system consists of a gasoline or diesel engine, a metal shaft, and a propeller. The engine sits inside the boat and is connected to an external propeller via a fixed shaft that runs through a special fitting in the hull. As the engine spins the shaft, so spins the propeller, which pushes the boat through the water. (If you’re not entirely sure how a propeller works, watch How do Propellers Work?). Motorboats with a straight inboard are generally steered by a rudder, a vertical appendage that directs the flow of water in one direction or the other, causing the boat to turn.
- Inboard/Outboard (Sterndrive): An inboard/outboard system—commonly referred to as a sterndrive—consists of an engine and an outboard drive unit. The engine sits inside the hull, while the drive unit (consisting of the transmission, steering mechanism, and propeller) is externally mounted. When the skipper turns the steering wheel, the entire drive unit turns, and so does the boat.
- Pod Drives: This relatively new propulsion system in recreational power craft consists of an inboard engine that is mounted to a drive unit underneath the boat. Like an inboard/outboard setup, the transmission, propeller, and steering mechanisms are all part of the drive unit. Unlike inboard/outboard systems, pod drives are typically mounted on the bottom of the boat’s hull and have the ability to swivel independently, offering superior vessel control. If you’re not familiar with pod drives, read All About Pod Drives.
- Jet Drives: Jet drive systems use an inboard engine to spin a metal impeller inside a large water pump. This pump sucks up seawater and then propels it at very high speed out the back of the boat. A good example of a jet boat is a personal watercraft (PWC), though there are a handful of watersports and cruising boats that use them. An external nozzle and bucket assembly is used to direct the thrust, thereby steering the boat.
- Outboards: An outboard engine has its propeller, transmission, and engine block in a single, self-contained unit that is mounted on the outside of the boat, typically on the transom. Cables and hydraulic rams are connected to the outboard to move it back and forth to steer the boat.
For a comprehensive run-down on all the different power options available to boaters, read Boat Motors: Outboards, Inboards, Pod Drives, Sterndrives, and Jets.
Types of Powerboats
There are almost as many different powerboat types out there as flavors of ice cream, and they’re all designed to do different jobs based on what people intend to use them for. If you’re wondering how to figure out the right sort of motorboat for you, consider browsing our What Type of Boat is Best for You? Top 10 Choices for Boaters feature. Though there are literally dozens of different styles of powerboats, here are the basic types you’ll want to know.
Bass Boat: A type of boat that generally has a flat deck, low freeboard, and a shallow draft and is used primarily for fishing on protected lakes and rivers.
Bay Boat: A low-freeboard center console fishing boat designed for near-shore and coastal use.
Bowrider: A powerboat with a seating area set in its bow.
Cabin Cruiser: Generally, any larger motorboat that provides sleeping accommodations within its structure. This generic term can be used to describe motor yachts, expresses, and a number of different designs.
Center Console: A powerboat with its console and helm located in a central location on deck.
Convertible: A boat with a flying bridge built atop the cabin, and an open cockpit aft.
Cuddy Cabin: A powerboat with a relatively small cabin on its bow section.
Deck Boat: A motorboat with a flat, open deck plan and without any below-decks accommodations. To create more forward deck space, most deck boats have a rather boxy shape, instead of tapering to a point at the bow.
Downeast Boat: A traditional style of boat that is derived primarily from commercial Downeast lobster boat designs of the American Northeast.
Dual Console: A boat with twin dashboards that are separated by a walk-through that allows access to a forward cockpit or seating area.
Express Boat: A sleek powerboat with a steering station on deck level, no flying bridge, and a cabin forward of and lower than the helm station.
Flats Boat: A powered skiff designed with an extremely shallow draft for fishing on flats and other shallow-water areas.
House Boat: Just as the name implies; these are boats that have a large home-like accommodations built on a barge-like hull.
Inflatable Boat: Any boat with an inflatable collar and a flexible bottom.
Jon Boat: Small utilitarian craft with a flat bottom, which are usually constructed of aluminum.
Motorsailer: A boat that relies primarily on engine power for propulsion, but also has a mast and sails to improve its passage-making efficiency.
Multi-species Boat: An open and rugged dual console boat with a utilitarian cockpit that’s designed primarily for fishing lakes and rivers. Most are constructed of aluminum.
Personal Watercraft: Small, open, jet-powered watercraft that can seat one to three people. Often abbreviated as “PWC.”
Pontoon Boat: A flat-decked boat with a perimeter fence built atop two or more aluminum pontoons.
Rigid Inflatable Boat: A boat with an inflatable collar built around a rigid fiberglass or aluminum hull. Also known as “RIBs.”
Runabout: A generic term used for any small powerboat, generally meant for day-boating with limited (if any) below-decks accommodation.
Mega Yacht: Extremely large, expensive yachts commonly 100' and longer in length. These may also be called "superyachts."
Tow (Watersports) Boat: A boat designed and built with an eye toward towing people who enjoy watersports such as wake boarding, wake surfing, or water skiing.
Trawler: A rugged, long-distance recreational powerboat designed for cruising, which resembles commercial fishing trawlers.
Walkaround: A boat built with side decks around the cabin, which allow people to walk around the cabin house and up to a foredeck.
While we’ll agree this is a lot of information to absorb, consider this page a resource you can reference over and over again as your basic powerboat knowledge grows. But don’t stop here. We also have articles covering the basics for buying and selling a boat. And once you have a boat of your own, you’ll want to make sure you know how to keep it in good shape by browsing our maintenance section. If sailboats are more your speed, be sure to read Sailboat Terms: Sailboat Types, Rigs, Uses, and Definitions. Finally, be sure to also review our seamanship section to make sure you’re running your boat in the smartest, safest ways possible.
Editor's Note: This article was originally published in August 2016, updated in January 2019 and March 2020 and 2021.