Inboard vs. Outboard Motors – Sailboat Needs

As a general rule, sailboats over 18 feet will have a motor of some type. They typically have an outboard motor if they are under 25 feet and an inboard diesel if they are above 25 feet. Newer boats are starting to come with electrical engines.

When there is no wind, a motor on your sailboat will be a huge help. There are many ways to add one, and which one should you get? Keep reading to find out more about boat motors.

If you have a motor and need to know how to mount it on your sailboat, click here to read my other article about installing an outboard!

Are Inboard Motors Better Than Outboards?

There are many factors to consider when deciding which engine to use, inboard or outboard. They both have advantages and disadvantages. As a whole, inboards are better when your boat is 30 feet or greater. If the boat is less than 30 feet, an outboard motor can be used.

Inboard motors are motors that are concealed down in the boat’s hull somewhere. For sailboats, the engine is normally under the cockpit and accessed from under the steps that lead down into the cabin. On most sailboats, especially older models, the inboards are diesel engines.

Sailboats use diesel because a diesel engine will last a lot longer than a regular engine. They have more power from less fuel as well. Diesel fuel has 20% more energy than regular gas. Diesel has a higher density which means it burns slower. You do get more speed and horsepower out of regular gasoline. Due to gasoline having a much lower density, it will burn faster creating more energy and HP.

The Hunter I used to sail on in the Destin, FL area would only have to be filled about once a year. The engine was only turned on when the wind was dead or we were trying to get in and out of the docks, but that is still a good amount of motoring. Imagine only having to fill your car once a year.

How much power should be your next question? Take a look at the next section to see how much horsepower you need.

How Much Horsepower Does A Sailboat Need?

As a general rule, you should calculate 1 horsepower(HP) per 550 pounds of weight. For example, a Catalina 22 weighs 2150 pounds. Take 2150 divided by 550 and you get 3.9. Always round up to avoid not having enough power. 4 HP is the right size engine for a Catalina 22.

I used to own a Catalina 22 and it had a 4-hp motor on it. The engine size was perfect for the size of the boat. Now, I couldn’t go 40 mph but the speed was good enough for me. When you are motor sailing speed is usually not a concern. Cruising slowly is the best in my opinion.

Let’s look at a 30ft boat. This is a very common size in the sailing world. A 30-foot Hunter Cherubini’s displacement is 9700 pounds. Displacement is another term for the weight of a sailboat. 9700 divided by 550 equals 17.63. I would round that up to 18 HP.

This is not an exact formula. It is a very good estimate compared to the other articles I have read about what size engine is needed for a boat. Usually, with a 30-foot boat, you will have an inboard engine instead of an outboard.

What Is The Most Dependable Outboard Motor – Top 6

When it comes to picking an outboard there are a lot of options. The average life span of an outboard is 1500 hours before maintenance or possible replacement. Take a look at the list below for some dependable options.

1. 2022 Tohatsu 6 HP MFS6DWDS

This is a great portable option. This is the most considerable single-cylinder option from Tohatsu. The shaft length is short at 15 inches. Some other features are, saltwater rated, 6 trim positions, low oil pressure warning indicator, and more. $1560.00

2. 2022 Mercury 3.5 HP Outboard Motor

The Mercury brand is a great one. We all know it and it’s very common to see all types of boats with a Mercury motor. This one has a 20-inch shaft, visual oil level indicator, 4 trim positions, and 360 degrees of steering. $1070.00

3. Suzuki 4 HP DF4AS3 Outboard Motor

Suzuki’s 4 HP motor is a good option for smaller boats. It has a short 15-inch shaft with a large easy-to-shift lever. It weighs 52 lbs which is a lot for this size of the motor. It has a fold-down tiller handle and 90 degrees left and right steering. $1245.00

4. Honda 5 HP BF5DHLHNA Outboard

Honda is a great engine creator. We all know the brand and love it. This motor comes with a 20-inch shaft. A 15-inch shaft is available. It also has a digital CD ignition for easy starting and low oil warning. There is even an option for a 6-amp charging system. $1742.00

5. Mercury 9.9 HP ELHPT EFI ProKicker Motor

This motor has an electric start! Making this a great option for convenience. It is on the larger size of power with 9.9 HP. It also has a power tilt button for easy positioning. It comes with a 20-inch long shaft as well. If you have plenty of money I recommend this one. $3720.00

6. Mercury 5 HP Propane Outboard Motor

That’s right, this outboard runs on propane! I have never experienced one of these but the clean burn is intriguing. Some of the other features are rated for saltwater and six trim positions. $1645.00

7. Suzuki 2.5 HP DF2.5S4 Motor

This little guy is a good option for the price if you don’t need a lot of power. It is only 29 lbs and has a 5-year warranty. The shaft length is 15 inches for those shallow waters. $819.00

8. HONDA 2.3 HP BF2.3DHLCH Outboard

For a smaller option with a good brand try this one. It has a 20-inch long shaft and 2.3 HP. The 5-year warranty means this will be your outboard for years to come. $978.00

9. Torqeedo Travel 1103 CL Electric Outboard

If you prefer no gas then this is the one you want. It weighs 39 lbs, has 3 HP, and is 29 1/4 in length. The best use is for a dinghy but if you had a small sailboat it could be great for motoring in and out of port. The price is a little high. $2999.00

Here is a link to my other article, How Do You Prepare An Outboard Motor For Summer – 6 Steps

When it comes to deciding which outboard motor to get just think about how fast you want to go and how big your boat is.

Are Outboard Motors Easy To Work On? Personal Experience

Outboard motors are very simple to understand making them easy to work on. If you ever have to deal with a broken down outboard motor, depending on the size, you should have no trouble figuring out the issue.

I had a Mercure 8hp motor on my sailboat and had to work on it a few times. One time it stopped shifting while caught in some high winds. Fortunately, popping off the top I saw that the shifter connection had come detached. I was able to attach it quickly and get the boat moving away from the rocks.

After returning to shore I made sure that would not happen again.

Outboard motors are basic engines that need basic maintenance to keep them running. If you have worked on any small engines before, this should be no problem for you to figure out especially since everything is on the internet these days.


Boatlifehq owner and author/editor of this article.

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