What Is An Outboard Boat Engine?

We often keep talking about big ocean liners and ships given the main theme of the website is based around that. Today we will be talking about outboard boat engines, which are commonly found in smaller boats but not on ships.

What is an Outboard Boat Engine

Outboard boat engine is a common propulsion system that can be often seen in boats. Such an engine is a self-contained unit in itself. It mostly consists of an engine, gearbox and a propeller. In some cases it also has a jet drive. They are always fixed in front of the transom. It is basically designed in such a way that they can propel small boats efficiently. They are also used in small water crafts by having more than one outboard engines fitted instead of a single engine.

The outboard engine can control the direction of the thrust. They are designed in a way that they can pivot over their mountings. Another major advantage of the outboard engine is that they can be removed easily. This helps in better maintenance and an easy repair. As the outboard engine can be removed there is another great advantage. When the boat hits shallow water then this outboard engine can be elevated to a higher position so that it does not get stuck. This can be done using both electronic and manual methods.

Working Diagram

The working of the outboard engine is explained easily with the help of this accompanying diagram


Outboard Motor Construction

1. this is the combustion chamber like any internal combustion engine where the fuel is burnt

2. this is the piston which moves to and fro in the direction indicated by the black two headed arrow

3. this is the crankshaft which converts reciprocating motion of the piston into rotary motion of the shaft and this is further transmitted via

4. driveshaft and through the

5. gear arrangement to the

6. propeller that provides the thrust required to move the boat

Of course this is an ultra simplified view and the real outboard motor would consist of few more parts depending on its type and size, say for example a starting motor to start the engine instead of hand cranking, more than one cylinders sometimes, camshaft, spark plugs and so on.

The outboard engine generally can be till four cylinder models. They are attached to the bracket of the transom. Many times they are linked to the control in the helm. The power capacity of these outboard boat engines is not huge and normally can expect them to generate upto say around 150 HP of power. This decides the maximum size of the boat they can be used in.

Portability and Uses

Outboard engines are easily portable. They can be used in different type of boats at the same time. They are not very expensive like the complicated motors. Outboard engine operate on a very simple technique this is exactly why they can be repaired and maintained very easily. It does not require a trained engineer unless the problem is very critical. The normal engine operators can easily control the outboard engines.

Pull Start vs Electronic Start

Smaller outboard engines mostly use manual pull cord system to start them. We are sure that you must have noticed outboard engine in many small boats. The outboard engine can weigh as low as twelve kilograms. The throttle and the gearshift control of the outboard engines are placed on the body of the motor.

The outboard engine is also provided with a tiller for steering. These reasons add on to the outboard engines being very light and easily portable. The outboard engine have integral fuel tanks. This is enough to allow the outboard engine to move a small dinghy.

The outboard engines are mostly used for various purposes. Some of the purpose is to power small crafts like jon boats, canoes, and other types of small boats. The outboard boat engine can also provide additional to sail boats that need extra speed while racing. The outboard engines are used for trolling the speeds of the large crafts. They play a vital role in the small boats. It is impossible to imagine the working of the small boats without the outboard engines.

Fuel Factor

Most of the outboard engine use petrol. There is diesel version of outboard engines also available. However, as we know that diesel engines are more complex. The cost of making diesel outboard engines is much higher. This is exactly why the diesel outboard engines are not found in most of the small boats. The outboard engine are also called trolling motors.

The outboard engine can cause pollution. This is exactly why they are not allowed in lakes where motor propelled boats are not allowed. They cannot be used on very small boats that can be rowed easily. They cannot be used as secondary means of propulsion in large crafts. The pollution from the outboard engine can be bad for the fish and other marine animals. The outboard engine is prohibited to be used in any occasion where the emission from the outboard engine cannot be ignored.

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