Why Do Sailboats Have Engines?

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The first time I went sailing, I was somewhat naive, thinking that it was cheating to use an engine to leave the dock. A few years later, owning my own sailboat, I totally understand the benefits of having a spare way of powering your boat.

Sailboats have engines (usually diesel) for a couple of reasons. One (1) it is safer and easier to exit and enter a marina. Two (2), if the sails cannot be used due to damage, too much wind, no wind, or going directly into the wind. The engine is also used together with the sails to travel faster.

In this article, I will explain why having an inboard or outboard engine on a sailboat is vital for safety and comfort.

Sailboat engine is added safety

Getting in and out of a marina

Getting in and out of a marina can be nerve-wracking, and that is while using the engine, something that you can out in reverse, slow down, and use as a way to turn the boat (more on that later).

Consider doing the same while having the sails up; not only are you not completely controlling the speed (the wind is), but there is no way to put the boat in reverse, making docking incredible hard.

Some people manage to dock with no use of the engine; this is usually done on smaller boats and in marinas with open spaces and a constant and not to hard wind.

The dangers are many, mainly financial risk since you will want to go as slow as you can to hurt anyone. The risk includes;

  • Not going fast enough;
    • The wind will push you downwind
    • Not enough water passing the rudders, making it impossible to steer
  • Going too fast:
    • Increased damage if crashing into something
    • less time to assess the situation and make correct decisions

Sidestepping in the marina

The propeller can also be used to turn the boat sideways without moving the boat forward or backward; this is accomplished through the inertia that the spinning propeller has. It is done by quickly revving up the engine for a few seconds, and before it starts moving forward, you let off the throttle, and the boat starts moving sideways.

Springin off the dock

This maneuver allows a boat to leave the dock while the wind pushes the boats’ side towards the dock. It uses a line as leverage and then runs the engine to counteract the wind and pushes the boat sideways towards the wind even though there is no bow thruster to push it sideways.

Added stability in rough seas

Suppose getting stuck in bad weather with strong winds and high seas; you might be sailing too fast with only a little sail up. And if you remove all the sails, you will lose control over the boat.

The solution is to reef all sails to a minimum and use the engine for extra speed and stability. Since using the engine allows you to go in any direction without considering the wind angle, you can now compensate for breaking waves and gusts of winds more safely.

Engine for comfort

As discussed above, having an engine is very practical and adds safety, but other factors make the engine a very useful piece of equipment on a sailboat.

Set a predictable speed

The engine can be set to a specific rpm independent of the wind; this means that it is easier to calculate when you will arrive somewhere. Often sailing takes much longer than anticipated due to changes in the wind that make the boat slower and the trip longer since there might be a need for the sailor to tack or jib to reach the destination.

What is the difference between tacking and gybing?

The engine can be used as an aid when raising the sails; many times, it is easier to hoist the sails when the wind is coming straight onto the bows. To make this work, the captain will steer the boat upwind until the sails are fully hoisted, then turn downwind and turn off the engines.

Use in combination with your sails

Combining sailing with your engines will do a couple of things; it reduces the fuel costs if traveling at the same speed, or:

Fuel saving tips!

If there isn’t much wind, it will increase your speed, and since a sailboat can move much like a pendulum if you only run your engines, putting up some sail area will make the trip more comfortable.

Man overboard situations

In situations where a crewmember has fallen overboard, the weather is expected to be rough with high seas and large waves. The situation is time sensitive, difficult, and requires the boat to turn around to assist the casualty.

Doing this with your sails up is not only extremely difficult but also very time-consuming. The standard practice is to let all sail area down, turn on the engine, and do a 180-degree turn whilst towing a line behind the boat that the person can grab on to.

Getting the person back on board is a difficult task requiring great handling of the boat while the sea is doing everything it can to make your day rememberable.

Engines can be used to check that the anchor is set correctly

Once the anchor is dropped and in position, the captain may use the engine to pull on the anchor chain and see if the boat starts moving away and he needs to reset the anchor or if the boat stays put and the anchor is holding firmly.

Towing another boat

If another boat loses its ability to steer or move, a second boat can assist in towing. What is usually done is that the towing boat will connect lines from the aft to the broken boat’s bows, and just like towing a car, it will be dragged to its destination.

In the final stages of the towing, the towed can be attached to the towing boat’s side; this increases maneuverability and reduces the risk of damage.

Types of engines

Inboard engines

Inboard engines are locatied inside the hulls, the only part that is in the outside is the propeller shaft or saildrive.

A saildrive is much like a gearbox and allows for a smooter and quieter operationg than the shaft and propeller setup.

Shaft and propeller is the most common setup and is basically just a tube sticking out through the hull where the propeller attaches.

Inboard engines are more protected from the weather; they take cooling water from the sea and usually creates a very noisy and smelly sensation inside the boat.

Inboard engines have fixed propeller positions and can only be controlled by raising or lowering the RPM.

Outboard engines

Outboard engines are standalone machines that can be removed from the boat. It is most common on smaller boats such as dinghies but can be the main propulsion on smaller sailboats; on a catamaran, there can either be one in the middle, one on each stern.

Outboard engines make the interior less noisy and keep the fumes outside, but are usually weaker and are more impacted by the weather. They are cheaper and easier to replace.

Usually, outboard engines are controlled directly by pointing the entire engine in the direction you want to go.

Electric motor

This type is still quite uncommon and expensive; the electric motor can be either outboard or an inboard type. The most common is to use lithium-ion batteries due to their high capacity.

Some DIY has been built off of golf cart motors, but there are also many professionally made ones.

The benefits of using electric motors are eliminating smells, no need for refueling liquids, fewer moving parts that require maintenance—less noise, and easier to repair.

The time it takes to refuel or recharge battery packs is much longer than it takes to refill a diesel tank; this hinders the range since there are not many quick-charge stations.


Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!

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