How Fast Does A 5hp Boat Motor Go? | LakeWizard

How fast does a 5hp boat motor go? The top speed of a boat motor depends on the boat’s weight and size, the weather conditions, and the brand of motor.

It’s fun to go fast! Whether you use your motor boat for fishing, exploring, coaching a rowing team, or just relaxing, everyone wants the most bang for their buck. Horsepower can be a hard unit of measurement to understand, so boaters often wonder how fast their new engine can actually get them.

Depending on the size and weight of the boat, a vessel with a 5ph motor can go 4 to 6 knots or 4 to 7 mph in ideal conditions. However, the top speed of a boat motor can be affected by the number of passengers and the brand of the boat motor.

The best way to determine the top speed of a 5hp boat motor is to test it out on a clear day with minimal weight on the boat. It is also important that the horsepower of the boat motor is suitable for the type and size of the boat. Using a motor on too large of a boat will result in overall slower speeds and more strain on the motor.

Sources include Boat International, Motor Boat & Yachting Magazine, Jon Boat Planet, Gone Outdoors, Formula Boating, and BoatSafe.

Table of contents


What Is the Top Speed of a Boat with a 5hp Motor?

The top speed of a 5hp motor will depend on the several factors:

  • The weight of the boat
  • The size of the boat
  • How many passengers there are
  • The weight of the gear on the boat
  • The weather conditions
  • The brand of the boat motor

There is a large amount of variability regarding the potential speed for a 5hp motor. In general, boaters assume that a boat with a reasonable load that is designed for a 5hp motor can go 4 to 7 miles per hour or 4 to 6 knots. There are also exceptions. Jon boats have a flat bottom, which allows them to skim over the water, so a 5hp motor on a Jon boat can make the vessel go up to 10 miles per hour.

How Does Horsepower Measure Speed for Boats?

Horsepower is a unit of measurement that is equal to 550 foot-pounds per second. That means that it measures the power of an engine by how much volume it can move in each second.

If it seems a little strange to use horsepower as a measurement for boats, that’s because it is. Horsepower as a measurement was invented by James Watts, who compared the ability of horses to power pumps to the ability of an engine to do the same amount of work. Watts discovered that the horses, on average, could lift 330 pounds of water a distance of 100 feet per minute. This measurement was simplified down to 33,000 foot-pounds per minute. This method of measuring power was immortalized and allied to motors, including boat motors.

Although it is confusing, horsepower is a more useful measurement for boat motors than miles per hour. MPH only has the ability to measure the distance traveled in a given amount of time. In reality, there are a large number of factors that can affect how far a vessel is able to travel.

Since people do not go fishing in a vacuum or within a physics equation, realistic things like the weight of the fishing gear and the beer cooler impact the speed of the boat. Additionally, boaters may face wind resistance, wakes, white caps, and underwater debris that can slow an otherwise speedy boat.

How Fast Can Different 5hp Boat Motors Go?

In controlled speed tests, boating experts put 5 different outboard motors to the test to see which 5hp motor could make a boat go the fastest. The boat used for the test was an Orange-Marine semi-rigid inflatable dinghy that measured 7.5 feet in length, 4.3 feet in width, and weighed 57 pounds, not counting the gear or the occupants.

Although each boat has 5hp in power, they do not all go the same speed, even in the same conditions. Factors like the weight and the efficiency of the motor can have a small impact on the motor’s top speed.

The Fastest 5hp Boat Motor

The Mercury F5 5hp outboard motor was the fastest of the 5 motors that were tested. It reached a stop speed of 5.5 knots (6.3 miles per hour) in 6.9 seconds. The Mercury motor weighs 55 pounds by itself.

The Slowest 5hp Boat Motor

The Lehr propane outboard 5hp motor was the slowest motor that was tested. It got the boat up to 4.5 knots (5.2 miles per hour) in 6.3 seconds. The second slowest motor was the Honda BF5 outboard 5hp motor. It was able to get the boat up to 4.9 knots. That converts to 56 miles per hour. From a dead stop, the Honda motor took 5.3 seconds to get up to top speed. The motor itself weighs 59 pounds, making the total weight of the boat itself 116 pounds.

While the Lehr motor was the slowest, it was also the lightest. It weighs only 48 pounds, so although it isn’t as fast, it may be ideal for boaters of smaller stature who want lightweight equipment.

The Middle of the Road 5hp Boat Motors

The Suzuki DF5 5hp outboard motor goes 5.2 knots, or 6 miles per hour, with an acceleration time of 6 seconds. This motor weighs the same as the Mercury, 55 pounds.

The Tohatsu MFS5 5hp outboard motor was slightly faster than the Suzuki DF5 with a top speed of 5.4 knots (6.2 miles per hour). The Tohatsu went from a standstill to its top speed in 6.5 seconds. Same as the Mercury and the Suzuki, this motor weighs 55 pounds by itself.

How Fast Can a Jon Boat Go With a 5hp Motor?

A Jon boat is a type of flat bottomed boat that is ideal for fishing in shallow areas. Although Jon boats are bigger and heavier than dinghys, they are able to go faster with the same engine. This is because a boat with a flat bottom can more easily skim over the water with less resistance.

A 5hp motor is suitable for a 12 foot Jon boat; some Jon boats this size can handle up to a 10hp motor. A 5hp motor on a 12 foot Jon boat can reach speeds of up to 10 miles per hour. Models like the Waco Jon 1432 Series, the Tracker Topper 1236, and the Lost Creek 12 Foot are all built for a 5hp motor.

How Do I Know What Boat is Suitable for My 5hp Motor?

The best way to determine the right amount of horsepower for your boat is to check your user manual. Most boats are manufactured with a recommended motor strength. It is important to avoid overpowering your boat because it is illegal in certain states and it can damage the hull of your boat.

Beyond manufacturer recommendations, the next best way to match boat to horsepower is to go by weight. It is recommended that a boat have 1 horsepower for every 25 to 40 pounds of boat weight. A 5hp motor can safely support a boat that weighs 125 to 200 pounds. This rule can have exceptions for certain types of boat, such as Jon boats and certain inflatable boats.

If you want to make your boat go faster with a 5hp motor, you will need to lower the weight to horsepower ratio. To calculate this, you will need to divide the horsepower by the weight of the boat. The lower that ratio, the faster the boat will be able to go.

Why is My 5hp Boat Motor Going Slower Than Usual?

Once you use the weight ratio or the manufacturer recommendations to match a motor to your boat, you may be wondering why your boat isn’t going as fast as expected. Even if you picked the best motor for the job and your boat is in good shape, there are a few factors that can limit the speed of a boat with a 5hp motor.

  1. Actual Boat Weight: This term describes the weight of a boat once it is fully fueled, has passengers, and is loaded up with gear. If there is too much weight on your boat, it will not go as fast.
  2. The Shape of the Hull: Flat hulls, planing hulls, and pontoons are the fastest, regardless of the horsepower of the motor. If you put a 5hp motor on a boat that is designed to displace water, such a boat with a rounded bottom, it will be slower than a hull that is not designed to displace water.
  3. Boat Length: If you use a horsepower to weight ratio, you can still get the horsepower wrong for the length of the boat. A 5hp motor is best for a boat that is 10 to 12 feet long. If you try to put a 5hp motor on a 14 foot boat, it is going to be slower and the motor will struggle. The exception to this is sailboats; a sailboat can be up to 21 feet long and only need a 5hp motor.
  4. Weather: Bad weather such as high winds, choppy water, and river debris can create resistance that will slow down your boat. If bad weather hits during a fishing trip, quickly get to shore and try again on another day.