Buying a boat means buying an opportunity for freedom. Many people looking for this freedom within a specific budget choose a small boat. Some people consider a small boat to be anything smaller than 64 feet. But 64 feet is still rather large, so we prefer to think of small boats as anything under 35 feet.

Regardless of the actual footage of your small boat, it needs an appropriate engine. As you look at engines, you may wonder how much horsepower you need for your small boat. To answer that question, you need to ask yourself the following questions.

How Much Does My Boat Weigh?

Weight is one of the most important factors in calculating appropriate horsepower. The best way to do this is to look at the manufacturer weight specifications. The boat manufacturer puts a safety placard on the boat for maximum horsepower rating based on how the boat is manufactured, its strength, hull design and other custom factors. A general rule some follow is to have 25-40 pounds of weight per 1 horsepower. To calculate the horsepower for your boat, divide the weight of your boat by 25 on the high end or 40 on the low end of horsepower needed. If your boat weighs 5,000 pounds, you may need a 125-200 horsepower engine but you can refer to the manufacturer safety placard indications to confirm the recommended horsepower rating. 

What Does the Manual Recommend?

If you’re not a math person, you can use other methods to decide on your engine and horsepower. One of the easiest options is to consult your manual. All boats should come with an owner or user manual that includes engine and horsepower recommendations. If you bought your boat from an experienced and educated broker, they may also have helpful suggestions about engine and horsepower options. Consult with these sources before you go engine shopping.

How Will I Use My Boat?

The equation we provided and your boat’s manual both provide a scale for horsepower. You can start at the low end of the scale with 25 hp or at the high end of the scale with 40 hp or whatever your manual recommends. How do you decide where to start, though? How you use your boat will help determine that answer. If you’re planning to use your boat in choppy waters or for water sports, you will need more horsepower. If you’re planning to use your boat on calm water or for more passive activities, you will need less horsepower.

How Many People Will Use My Boat?

Knowing how many people will use your boat will also help you determine where to start on the scale of horsepower calculations and recommendations. Unfortunately, this requires more calculations. You will need to multiply your boat’s length and width in feet, then divide that result by 15. The result of the entire equation will tell you how many people can safely fit on your boat. For example, if the boat is 7.5 feet long and 4 feet wide, multiply those two numbers together. The result is 30. When you divide 30 by 15, you get 2. Two people who weigh 150 lbs. can safely fit in your boat.

After you ask yourself the above questions, you can again ask yourself, “How much horsepower do I need for my small boat?” After making the necessary calculations and asking experts for recommendations, you’ll know what horsepower you need. RJ Nautical sells Yamaha outboard motors with various horsepower, so we can help you find the perfect motor with the right horsepower for you.