Boats

5 min read

Inboard vs Outboard Motors: Choose Your Sea Adventure

Imagine the spray of the sea on your face as you debate between inboard and outboard motors – the heart of your aquatic adventure awaits your choice. Let's dive into the mechanics of marine bliss!

Tobi Miles
November 1, 2017

Choosing a boat is difficult when you have so many factors to consider such as brand, size, power, and engine. A boat’s engine ultimately determines what you can use it for and how long it will last. Boat enthusiasts throughout the world struggle to settle the age-old date: inboard vs. outboard.

Inboard engines offer more horsepower than outboard engines, but outboards are lighter which can boost your speed. An inboard engine requires less maintenance and can go 1,500 hours before you need to service it. Outboard engines are quite loud but they take up less space than inboards so you get more storage for cargo, fish, and passengers.

It’s also easier to maintain an outboard than an inboard, but you’ll need to do it more often. Watersport enthusiasts typically prefer inboards because there is no exposed propeller in the back. Follow along as we explore the difference between inboard and outboard engines and see which one is best for you.

What Is The Difference Between Inboard and Outboard?

An inboard engine is centralized within the boat whereas an outboard is located at the back of the boat. The propeller on an outboard sticks out, and there’s typically a handle for you to adjust the engine. Inboards are different in that there is a separate drive shaft for the engine because it isn’t exposed like an outboard.

These may sound like minor differences, but they affect everything from the handling and price to maintenance and purpose. Let’s take a look at the key criteria in which inboard and outboard motors are unique.

Horsepower

You can expect superior horsepower with an inboard engine over an outboard engine. The key difference is that you can boost your boat’s horsepower if you add another engine. This pricey option is common for boaters anxious to reach high speeds, but it’s not always worth it.

Many experts recommend choosing an inboard engine instead because you don’t have to worry about servicing multiple engines. That way, you get superior horsepower without having to spend extra money on maintenance and replacements. Granted, the initial cost of a boat with an inboard engine is more expensive, but you also get more horsepower than a stock outboard engine.

While you can often get more horsepower with an inboard engine, a boat with an outboard may go faster. That is because boats with outboard engines are typically lighter than boats with inboard engines. You will add weight if you install a second outboard engine, but you will also get a speed boost and maximize both engines’ horsepower.

Performance

You can typically expect better performance with an inboard engine than with an outboard engine. Generally, a single outboard engine isn’t strong enough to power a large and heavy boat. You can solve this problem by adding another engine, but that can be expensive and entails more maintenance.

Boats with outboard engines are often quite light which makes it easy to navigate and turn or shift quickly. It’s also easier to dock a boat with an outboard engine because of the extra control when you cruise at low speeds. Another key benefit of outboard engines is that they have plenty of storage space without sacrificing speed.

However, inboard engines offer better fuel efficiency and they are easier to steer. Driving a boat with an inboard engine is similar to driving a car which makes it accessible to beginners and experts alike. Inboard engines have a longer lifespan than outboards, so you can count on a smooth performance for years to come.

Fishing

Inboard is better than outboard when it comes to fishing because of how loud outboards are. The loud operation of an outboard engine can easily scare fish away. Of course, you can always turn off your engine when you find a good fishing spot, but it may be too late by then.

Fish will hear the roar of an inboard and outboard engine, but an outboard’s propeller is louder. Luckily, outboard engines offer plenty of control, so you can slow down once you approach a great spot to minimize noise. That is less of a necessity with inboard engines which makes them the best choice if you primarily fish with your boat.

However, storage is a major benefit when you go fishing with a boat that has an outboard engine. That is because of the extra onboard storage when you have an outboard engine. This will let you catch and store as many fish as possible without having to release some of them into the water.

Maintenance

Outboard engines are high-maintenance when compared to inboard engines. You need to inspect and maintain an inboard engine every 700-800 hours of use which is quite often for frequent boaters. Inboard engines can go up to 1,500 hours before you need to bring them in for maintenance and repairs.

That means that you can potentially spend up to double on maintenance for an outboard than an inboard engine. With that said, it’s easier to maintain an outboard engine if you forego professional help because of how accessible it is. Inboard engine maintenance requires you to work inside a small access hatch which can be difficult.

That is why it’s easier to hire a professional to service your inboard engine. You don’t even need to take your boat off the trailer to service it if you have an outboard engine in many cases.

Durability

Outboard engines typically only last half as long as inboard engines. Inboard engines get more protection than outboards because they are almost encapsulated within the boat. You may be able to get over 4,500 hours out of an inboard engine as long as you maintain it every 1,500 hours or sooner.

However, an outboard engine may only last 2,000 hours in total even if you maintain it every 750 miles. This is primarily because outboard engines are more directly exposed to water than inboard engines. Boats with outboard engines are also more durable when it comes time for the winter.

You can winterize an outboard engine much more easily than an inboard. This will save you time and money if you live in a climate where the water freezes in the fall and winter. Failure to winterize an inboard or outboard motor can cause thousands of dollars in repairs.

Weight

Inboard engines weigh much more than outboard engines, and that makes a bigger difference than you may think. Most inboard engines weigh between 480 and 1,100 pounds, but they typically err on the heavier side. This can affect your boat’s speed and mobility as well as limit your onboard storage space.

Conversely, outboard engines only weigh between 150 and 400 pounds, on average. You can still find outboard engines that weigh closer to 1,000 pounds, but that is rare unless you have a large boat. Even though you usually get less horsepower with an outboard engine, the lighter weight makes up for it.

This can let you cruise at higher speeds and also helps explain why you get so much control with an outboard. With that said, the heavy weight of an inboard engine comes in handy when drifting because it helps keep your boat steady. You can still drift if you have an outboard engine, but you won’t have the same center of gravity as an inboard.

Price

Boats with inboard engines are typically more expensive than boats with outboard engines. This applies to the initial expense, but most modern inboard engines have superior fuel efficiency.  The fuel efficiency that inboard engines offer makes it easier to justify spending extra money initially.

Longevity is another factor that makes it worth the extra cost for a boat with an inboard engine. You also have to consider the extra cost of maintenance and engine replacement when it comes to outboards. With that said, it costs up to $15,000 to replace an inboard engine on a boat which can be intimidating.

Outboard engines can cost as little as $900 and as much as $10,000 or more. You’ll need to replace it sooner than an inboard engine, but the initial cost is quite low. You’ll also double your costs if you add a second outboard engine to your boat to increase the speed.

Inboard Pros and Cons

Inboard engines are desirable to any boat enthusiast, but they aren’t without their faults. The safety and fuel efficiency is offset by the difficult maintenance for some enthusiasts, for example. Let’s take a look at the benefits and downsides of inboard engines.

Pros

Fuel efficiency is among the biggest selling points of inboard engines. Generally, inboard engines only go through 10-11 gallons of fuel per hour while sailing at 25 knots per hour. That is up to 5 gallons less fuel per hour than an outboard engine, and that makes a huge difference.

Safety is another major benefit of inboard engines, especially if you use your boat for watersports. You don’t have to worry about an exposed propeller that could cause serious injury. Boats with inboard engines also have a larger platform because there is no engine at the back of the boat which makes it safer to enter and exit.

The easy steering that boats with inboard engines have to offer is ultimately one of the biggest benefits. You can steer a boat with an inboard engine like it’s a car making them more accessible than outboard engines. Finally, you get much more longevity with inboard engines than with outboards which is worth the added cost.

  • Safety
  • Longevity
  • Easy to steer
  • Fuel efficient

Cons

Boats with inboard engines are typically heavier than boats with outboard engines. This isn’t a big deal if you have enough horsepower, but it can make it difficult to navigate certain areas. Possibly the biggest downside of inboard engines is how hard it is to maintain them.

Unlike outboard engines, you cannot maintain an inboard while it’s on a trailer and instead have to elevate it. This means that you’ll have to pay to have it serviced unless you have plenty of experience with boat repairs. It is also difficult and expensive to winterize an inboard engine compared to an outboard.

Unfortunately, you also sacrifice storage space with an inboard engine. The engine takes up space within the boat itself which can be quite frustrating if you need to haul cargo or store fish.

  • Maintenance is difficult
  • Hard to winterize
  • Heavy
  • Minimal storage

Outboard Pros and Cons

Outboard engines have become more and more popular, especially for boaters on a budget. They are light and fast but also don’t last as long as inboards. Understandably, many boaters are torn between the two. Let’s take a look at the pros and cons of boats with outboard engines.

Pros

The biggest benefit of an outboard engine is that they are so easy to maintain. You may not even need to bring your boat into a shop to make simple repairs. Experienced boaters can make simple engine repairs while the boat is on the trailer in most cases.

They don’t take up any space because outboard engines are located at the back of the boat which lets you maximize storage. Outboard engines are light compared to inboard engines which can help you go as fast as possible. This also comes in handy when you need to attach your boat to a trailer and transport it to your home or a marina.

Winterization is so easy with an outboard engine that you may not even need to hire a professional if you have experience. You can typically winterize a boat with an outboard engine for $200 which is a great deal.

  • Simple maintenance
  • Light
  • Fast
  • Easy to winterize

Cons

The loud operation of an outboard engine is a major downside unless you don’t mind the noise. Outboard engines don’t last nearly as long as inboard engines, and they need to be serviced at least every 750 hours. You may even need to replace your outboard engine after only 2,000 hours, and that can cost as much as $10,000 in some cases.

The poor fuel efficiency of outboard engines is also a major downside. You may use up to 16 gallons of fuel per hour while sailing at 25 knots per hour with an outboard engine. This is doable if you don’t always sail at high speeds, but it can add up quickly and it may be worth considering an inboard.

  • Loud operation
  • Doesn’t last long
  • Requires frequent maintenance
  • Poor fuel efficiency

Inboard Vs. Outboard Vs. Sterndrive

Sterndrive is an alternative to inboard and outboard engines that combines the best of both worlds. These engines are less common than standard inboard or outboard models, but they are a great choice. A sterndrive engine is located in the back of the vessel beneath the transom, and the drive unit is under the deck.

Many boaters and enthusiasts prefer sterndrive engines over inboard and outboard motors. That is because of the increased speed that sterndrive engines afford you even compared to an inboard with the same horsepower. They also use less fuel than an inboard engine, making sterndrive engines a more practical choice.

You get more rear access with a sterndrive than with an inboard engine. With that said, they also require more maintenance than either an inboard or outboard engine which is the main downside.

Are Inboard Motors Bad For Saltwater?

Inboard motors are susceptible to damage after prolonged exposure to saltwater. They are constantly submerged in the water so there is no way to escape the corrosion. Saltwater is bad for almost all components of a boat, especially if they are made of metal.

Outboard engines can handle saltwater better than inboard engines, but only by a small margin. The entirety of an inboard engine is submerged in the water, but that’s not the case with outboard engines. Part of an outboard engine sticks out the water which can help spare it from saltwater.

You can flush saltwater out of outboard engines every once in a while to extend their lifespan. This is possible with inboard engines, but it’s quite difficult and you will likely need to hire a professional. That is because you’d have to lift the boat and work within the cramped access hatch. However, flushing your engine is worthwhile whether you have an inboard or outboard engine.

How Reliable Are Outboard Motors?

Outboard motors are quite reliable, albeit not as reliable as inboard motors. They weren’t always as reliable as they are now, and modern technology has made outboard engines much better. For example, the standard used to be 2-stroke outboard engines which were prone to many problems.

Brands like Suzuki and Honda have refined outboard engines and made them much more reliable. Now, the standard is 4-stroke outboard engines which offer much more power. Steer clear of 2-stroke outboard engines if you look for used boats because you will need to maintain them frequently.

Are Inboards Safer Than Outboards?

Boats with inboards are safer than outboards when it comes to boarding the vessel. You have more space onboard which makes it easy to board a boat without having to squeeze in. Boats with outboards require you to step around the propeller in some cases which can be tricky, especially if the boat is wet.

The swim platform on a boat with an inboard engine is also safer because there is more space. Watersports are also much safer if you have a boat with an inboard engine. Waterskiing can be dangerous with an outboard engine because the propeller is exposed so someone could easily run into it.

With that said, you are sadly at a higher risk of fires with an inboard engine than an outboard. This is because inboard engines are contained within the boat which makes it easier for them to catch on fire. Otherwise, there is little difference in safety between inboard and outboard engines for boats.

Which Is Better Inboard Or Outboard Engines?

Inboard engines are better for fishing and watersports whereas outboards are cheaper and easier to maintain. With that said, you will need to service an outboard engine much more often than an inboard engine. Outboard engines need to be serviced every 750 hours and inboard engines can go 1,500 hours before you repair them.

Inboard engines also last up to 3,000 hours longer than outboard engines before you need to replace them. You get more storage with a boat that has an outboard engine because it doesn’t take up any space onboard. This comes in handy for fishing, storing cargo, and having as many passengers as possible. Both inboard and outboard engines are great choices, but inboard engines offer more horsepower and better fuel efficiency.

Article updated:
January 5, 2024

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