Similarities and Differences Between Outboard and Inboard Engine

Basic Situation

There are two main types of sailboat engines. They are inboard engines and outboard engines. The propeller of the inboard engine is at the bottom of the ship, and the engine is inside the ship. The outboard engine body and propellers are on the outside of the stern.

When choosing between a large day sailboat (not for overnight sailing) or a small sailing boat, you may be faced with a choice between a sailboat with an inboard engine or an outboard engine. Both have advantages and disadvantages.

The two engines are similar in many ways. They use about the same amount of fuel. It's just as hard to buy accessories or find a mechanic when something goes wrong. Owners can easily master standard maintenance techniques for both. The operation control method is similar. But there are still important differences.

Pros and Cons of Inboard and Outboard Engines

Advantages of Inboard Engines

1. Most inboard engines are diesel engines, which make them more reliable, less costly, and cheaper to maintain. And it eliminates the danger of gasoline.

2. A Marine diesel engine, if well maintained, can last almost a lifetime (many diesel engines in their 30s are still working well on ships).

3. The weight of the engine is in the bottom of the ship, which makes it a good ballast for improving the stability of the ship.

4. Inboard engines are usually invisible and not thought of -- nor do they affect the beauty of the ship's exterior.

5. Generally speaking, most ships equipped with inboard engines have more power generating capacity and are therefore equipped with more powerful navigational systems and equipment.

6. The propeller is deep underwater, thus reducing the possibility of idling due to the tide.

Disadvantages of Inboard Engines

1. The inboard engine is heavier, so the ship is slower.

2. It is usually packed in a narrow space, so it is more difficult to maintain.

3. It is difficult and expensive to dismantle or replace an inboard engine. Sometimes you have to cut the fiberglass hull.

4. If you remove the inboard engine, it is more expensive to replace it with a new inboard engine than an outboard engine of similar size.

5. The inboard engine takes up a large amount of cabin space.

6. When the propeller shaft departs from the bottom of the ship, the inboard engine needs shaft sealing, which increases the risk of water inflow inside the ship (rare, but deadly).

Advantages of Outboard Engines

1. outside the ship, easy to operate.

2. disassembly is much more convenient.

3. In most cases, the propeller can be lifted out of the water by raising or tilting the engine. This makes sailing with less drag – and reduces the risk of entanglement or breakage in the water.

4. Depending on the fixed mode, some engines can be moved to increase steering performance in narrow Spaces.

5. Outboard engines are cheaper than inboard engines.

It is worth mentioning that outboard machines produced by our company have all the advantages mentioned above and are a good choice for purchase.

Disadvantages of Outboard Engines

1. Many people think outboard engines make ships look ugly.

2. Because the propeller is not deep in the water, it may idle when the stern is raised in the rough sea.

3. Unless the ship is well designed, petrol tanks may be placed in strange or even dangerous places.

4. The old two-cylinder engine was noisy and smoky.

5. Oversized outboard engines throw the boat off balance.

As with any decision to buy a sailboat, the best type of engine depends largely on the intended use of the vessel. Also, it's worth noting that most sailboats that are big enough to have an engine are typically equipped with an inboard or outboard engine, so you don't usually have to choose your own. But you might still be torn between vessel A with an inboard engine and vessel B with an outboard engine. However, as ships depreciate, engines sometimes need to be replaced. Some ship owners install an outboard engine in place of an inboard engine, but rarely the other way around. 

Since ships with an original outboard engine generally don't have room in the cabin or support structures for later engines. If you're considering buying a used boat with an outboard engine instead of an inboard engine, be careful when you test drive. For example, if a large outboard motor is installed, the ship may become unbalanced due to its weight. Its tail will be weighted, with the saying tends to "squat" in the water, and affect navigation. Also, check that fuel tanks are properly installed to ensure that they do not accumulate below deck and pose a risk of explosion, even if leaks or emissions occur.