Outboard vs Inboard – Difference Between Inboard And Outboard Engines


inboard vs outboard motors compared

So you want to buy a boat but you are completely new to boating. You know which boat you would like to buy but don’t really know if it will fit your lifestyle. You finally know what you want, you go to the dealership and there you get hit by a question. Which motor would you like to buy, inboard or outboard?

What is the difference between the outboard and inboard motor?

The difference between the inboard and outboard motor is that the inboard motor is inside the hull of the boat, within the space specifically designated for the engine.

The outboard motor is attached to the transom of the boat and it has a self-contained engine and housing.

Typically inboard engines use diesel fuel which gives them more power and trust, while outboard engines use regular gas.

To find out if the outboard engine is better than the outboard, we need to compare them in detail. So to start off, let’s look at each engine individually first.

What is Inboard Engine

Inboard vs outboard motor compared

As noted above, the inboard motor resides inside the hull. That space on the boat that was specifically designed for an inboard engine. The inboard engine is permanently mounted. It has a separate propeller, rudder blade, gearbox, stern tube, driveshaft, an exhaust line, raw water line, outfitting, etc.

Typically inboard motor is mounted horizontally inside the hull. It is below the waterline. The watertight stern gland connecting it to a shaft and propeller which are outside of the boat and inside water. The boat is using a traditional rudder mounted behind the propeller for steering.

Types of Inboard Motor

There are two different types of inboard motor, V-Drive, and D-Drive.

V-Drive inboard motor

Mounted in the back of the boat with a V looking driveshaft from the transmission which produces a much larger wake perfect for wakeboarding and wake surfing.

D-Drive inboard motor

The motor is mounted in the center of the boat with a drive shaft attached to the transmission and produces a smaller wake which can be used for water skiing.

Where are Inboard Motors Used the Most

Inboard motors are typically used on larger boats and ships. Those ships require a lot of power and trust, as well as better gas mileage. They are also used in large and deep bodies of water, such as oceans.

It is not a good idea to use inboard motors in shallow lakes and rivers because you can not lift the propeller out of the water and can damage it on the rocks below.

Advantages and Disadvantages of Inboard Motors

There are some notable advantages and disadvantages of inboard engines that everyone should consider when trying to decide between the inboard and an outboard engine.

For start, boats with inboard engines are typically more expensive and require a lot of space on the boat. They do make up for those disadvantages with the fact that the motor is more powerful than the outboard motor (more horsepower and torque) and at the same time use less fuel because they are built similar to car engines.

Another advantage is that because the engine is located under the deck, it is quiet. This helps you entertain your friends better. At the same time, maneuverability will suffer, especially when you are trying to dock or go backward.

Because of the location of the inboard motor and inability to remove it, loading onto a trailer can be difficult. The location of the engine causes another issue, it has a greater chance of catching fire. It can get hot under the deck. If there is no air for the engine to breath it may overheat and burst into flames.

What is the Outboard Engine

outboard compared to inboard motor

The outboard motors are the most common propulsion system in small and midsize boats. They are chosen by boaters because they are small, practical, agile and have good power to weight ratio.

Unlike the inboard motor, the outbound motor is visible to everyone. It is positioned at the back of the boat attached to a transom. An outboard engine is a self-contained unit that includes engine, propeller, steering control, and gearbox.

Where are Outboard Motors Used the Most

Outboard motors are used everywhere but the majority are used on smaller boats in lakes and rivers. They are very convenient for shallow water. You can lift the propeller out of the water in case you come across rocks.

Fisherman love outboard motors. They are easy to steer and can get them to any part of the lake or river with ease.

On the other hand, a fisherman might like inboard engines as well. Inboard engines give more room on the deck and their fishing lines are less likely to get tangled on an engine.

Advantages and Disadvantages of Outboard Motors

One big advantage of outboard engines is that they can be removed and stored away. This also helps when you have a mechanical problem, everything is so much easier to reach than inside the inboard engine.

The Outboard engine is less powerful and uses more fuel, but at the same time maneuverability is so much better than with the inboard engine. That, however, changes if you are in rough waters.

Inboard is better here because it is in the water 100% of the time while the outboard can be out of the water significant amount of time, depending on the wave height.

Another advantage of the outboard engine is not really related to the engine itself but rather the ability to sell your boat in case you chose to do so.

Why do I say that?

You can very easily change your mind about a good looking boat as soon as you open the door to the engine room. The engine area is not a clean space. It makes people think that the boat is not in good working condition because of that.

You will not have that problem with an outboard motorboat because the motor is easy to replace. That is definitely something to think about when buying a boat.

Inboard vs Outboard

The question here is not which engine is better, but which engine you should pick based on what kind of boat you have and what the purpose of your boat will be.

The Outboard motor is perfect for smaller boats, fishermen and those who use their boats in lakes and rivers. If you live in areas of the country where you have 4 seasons and can not use your boat for an extended period of time, the outboard engine is your best bet. You can take it out, store it away and winterize it much easier.

On the other hand, if you are thinking of buying a large boat where you are going to entertain your family and friends, the inboard engine makes more sense.

To match the power of the inboard engine, you will need more than one outboard motor which of course will increase fuel consumption. Inboard engines are hard to fix because they are usually cramped inside a very tight space and winterizing inboard motor can be a real pain.

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