Sailboats are designed to harness the wind and travel where ever they want to go, right? But many people don’t realize that many modern sailboats are also motorboats—they’ve got sails for sailing and engine power for motoring. Why? Let’s take a closer look.
Table of Contents
- Do Sailboats Have Engines?
- Why Have a Sailboat Engine At All?
- Can You Sail Without an Engine?
- Types of Sail Boat Engines
- Maximum Hull Speed and Beyond
- Sailboat Motor FAQs
Do Sailboats Have Engines?
The answer is a familiar refrain that you may have heard before—it depends! Small sailboats and sailing dinghies typically sail without the aid of an engine. These are easily rowed should it come to it, and clubs and races often organize tows to and from the racecourse.
However, the bigger the boat, the more likely it is to have a motor of some kind. The reasons to have a motor are many, but there are certainly plusses to doing without.
Why Have a Sailboat Engine At All?
There is a romanticism to sailing everywhere and never running an engine. When you dream of the old days, with beautiful wooden schooners and sailing ships plying the seas for trade and exploration, a motor never enters the fantasy. They didn’t have them back then!
And if Blackbeard never turned the ignition key, why should you! Well, probably because a lot has changed in boating in the past few hundred years. Here are a couple reasons why having an engine onboard a sailboat is pretty nice.
Maneuvering in Crowded Spaces
For one thing, most of us boat differently than they did back then. Chances are, you pull into a crowded marina after a day of sailing. If you visit new ports, you may anchor in the harbor, but sometimes you take a dock to explore the town.
And that brings up the first reason to have a motor—safe close-quarters maneuvering. While it is possible to maneuver a sailboat alongside a dock and safely tie up, it requires having a face dock and wide-open space to maneuver.
Even still, it is, without a doubt, easier and safer to approach a dock under power. Having an engine means having a reverse gear, which is the closest thing you can get to having a brake pedal on the water. Reverse power enables you to slow down and to stop!
And if you keep reversing, it enables a boat to back up. Many marinas are set up in a way that requires you to do this. It’s not impossible to back a boat up under sail, but it can’t be done without several crew members and some open space to maneuver.
For these reasons and others, boat operators are restricted from sailing when there won’t be enough room to maneuver. Some marinas even ban docking under sail, and it’s often not allowed when passing under bridges or through narrow canals or locks.
Motoring Through Calms or Upwind
The next advantage to having a motor on your sailboat is the ability to motor when the sailing isn’t good enough. Small boats and dingies can usually make way in light wind, but heavy cruising boats are an entirely different story.
If the wind drops below ten knots, many boats have trouble making way under sail. Even if they can sail, their skippers and crew might not be ecstatic to be cruising at two or three knots.
For example, imagine you planned a day trip to an island across your home bay. The island is only 18 miles away. You set out in the morning with a wind forecast of 10 to 15 knots. If you’re able to make six knots (usually a very attainable number), the trip should take you three hours.
But after leaving the dock and hoisting the sails, you notice that the wind is not filling in as forecast. Instead of 10 to 15, you are experiencing 5 to 10, or even lighter. The sails aren’t filling with air, and your speed over the ground (SOG) is only three knots. It’s now going to take you six hours to make your trip.
But, unfortunately, the tide is changing in another hour, and an adverse current will be forming. That will slow your boat down another knot, meaning your SOG will go down to two knots. So the trip is actually going to take even longer–now nine hours!
This news comes as a disappointment because that means you won’t arrive until after dark. You’ve never entered the channel at the destination, so you need good light to get in and see the markers.
This is just an example of a time when a crew might choose to use their engine. They can turn the ignition and put the motor in gear, and charge on through those light winds at six knots. The three-hour trip will take a predictable three hours, and the wind tide will have less effect on the SOG.
The same is true should the wind happen to be on the nose. A sailboat cannot go sail directly into the wind, so if they need to go in that direction, they can tack back and forth or motor directly into the wind. Again, the motor provides an option that the crew did not have before.
Motorsailing
The scenarios described above are doubly true when discussing a heavy cruising boat. These boats require more wind to get them moving, and they sail poorly upwind. Therefore, tacking back and forth is usually a less desirable option in such a boat.
But it is possible to both sail and motor. In sailor terms, this is called motor sailing.
Motorsailing is very effective thanks to a trick that happens with the apparent wind. The apparent wind is the wind that the boat experiences—it’s higher when you sail into the wind since the speed of the boat is added to the speed of the wind.
So if you are sailing into five knots of wind, the boat might be making two knots of speed. The apparent wind, and therefore the wind passing over the sails, is seven knots. Most boats sail poorly in seven knots of wind.
But if the skipper turns the motor on and puts the engine in gear, the boat will be making five knots or so of speed. Now, the apparent wind on the sails is more like ten knots, and most boats can sail pretty well in ten knots of wind.
Some boats are designed to be great motorsailers. A motorsailer is a boat that doesn’t sail great on its own. Instead, the sails work with the motor to reduce fuel consumption and increase the boat’s overall speed.
Can You Sail Without an Engine?
Now you have some idea why sailing with an engine is a great idea—but do you need one?
Of course, it is possible to move a sailboat without an engine. With good planning and an experienced crew, any sailboat should be able to maneuver and make way under sail.
Skippers would still need a plan of action when it comes to tight marinas and anchorages. For example, will they have a long skulling oar onboard? Will they only use open face docks where they can dock under sail? Will they only pick up moorings or anchor?
What about when the wind dies? Sailing without a motor will require a greater amount of flexibility. In real-world sailboat travel and cruising, a motor gives you options you would otherwise not have. Can it be done? Of course, it can. Is it easy? No, not really.
For example, there are trips that you cannot make at certain times. When crossing from South Florida to The Bahamas, the Gulf Stream current necessitates careful weather planning. As far as the weather is concerned, the best sailing winds are most likely to come from the north. But north winds are exactly when you should not cross since the wind against current builds up dangerous and uncomfortable seas.
Most sailors wait in South Florida for southerly or westerly winds. Sometimes, this means waiting a few weeks for the one or two days when this might happen. What if you’re sitting there, waiting for weather, and instead of a day of 10 to 15 from the south, you were blessed with 48 hours of “light and variable” winds?
If you had no motor, “light and variable” appearing in the forecast would not make you happy. But if you’re ready to cross to The Bahamas, you have a strong motor, and the weather gods are smiling, “light and variable” might be the best thing that could happen. Nothing is more beautiful than crossing the Gulf Stream on flat-calm glassy water without a breath of wind.
Types of Sail Boat Engines
Most sailboats have either a small gasoline outboard engine or an inboard diesel engine. Diesels are the preferred option for several reasons, but outboards can be an economical option on smaller boats.
Outboard Motor
Outboards are common on smaller sailboats that are 25 feet long or less. They are usually small, portable models of eight horsepower or less.
One of the significant advantages of this size engine is that it is easy to take on and off the boat for maintenance or storage. They’re also relatively inexpensive to replace. For example, if the boat needs a new motor, you can usually find a new or used one and install it on the boat in a matter of minutes.
The downside is that sailboats are not well-designed to be powered by outboards. A few designs use these motors successfully, but generally, the tall transoms and deep cockpits found on sailboats make it hard to use an outboard. Many have to be retrofitted with an ugly and less-that-ideal bracket to even mount the outboard.
Besides being awkward to use and operate, the boat doesn’t do very well under outboard power, either. The propeller will likely pitch out of the water when the bow goes down a wave in any kind of rough sea. This will result in a loss of steady power and reduce boat speed and maneuverability. In rough conditions, this could be catastrophic.
Outboard motors can easily be rigged to be operated by remote control from the cockpit helm controls. Unfortunately, finding this on a sailboat is rare. Instead, designers slap them on the back of the boat like an afterthought. What you’re left with is a difficult control situation, where you have to lean over the transom of the boat to put the motor in gear or move its tiller or throttle.
Some catamarans use outboards that are mounted in wells on the bridge deck. Since the catamaran’s design allows this, these outboards tend to be larger and can power larger vessels. There are 36-foot or more catamarans that have a pair of outboards for power.
Diesels Inboard Engine
Compared to the small gas outboards, an inboard diesel engine is an enormous monstrosity. But by having a propeller shaft coming out of the bottom that is always underwater, the design solves the dangerous shortcomings of outboards.
Diesels are also placed in the boat for perfect weight distribution. They are usually mounted under the cabin sole or the stairs to the cockpit. And since the boat’s interior is designed around them, they can grow as the boat grows. A bigger boat can get a bigger engine, whereas outboards are generally limited in size due to their mounting location.
Both diesels and outboard can provide decades of service when well maintained. But diesels take the cake as the most reliable option. Diesel fuel vapors are also less explosive than gasoline fumes, making it the safer option to carry on vessels with enclosed cabins.
And finally, diesel engines are easy to work on and understand. The types of motors installed in the average cruising boat are the sort of small three to six-cylinder diesels that you might find in a farm tractor or forklift. Parts are often easy to get, and finding someone who can fix one is usually pretty straightforward.
The downside of the diesel inboard is its cost and complexity. For example, a new diesel inboard will cost you at least $10,000 for a small one, plus the labor to install it. On the other hand, an outboard will cost around $2,000 and will require no installation at all.
A diesel inboard will have a complete control panel at the helm, allowing you to start and stop the motor and control the gear and throttle from the helm. You will steer the boat with the regular helm, which turns the rudder.
A big plus, however, is that the rudder is mounted right behind the prop. This means that you can use bursts of power from the engine to force water over the rudder, making maneuvering easier during docking.
Inboard boats are typically considered to be a little more challenging to dock than an outboard-powered one. But once you get the hang of the basics, they provide you with a lot more options and easier control in tight spaces.
Electric Inboard Motor
Imagine sailing with no motor noise at all. As with land vehicles, electric-powered sailboats are getting a lot of attention right now. At this point, fully electric yachts from the factory are few and far between. But many owners have retrofitted older boats with inboard electric motors.
As with all-electric vehicles, the trick is balancing how much power the motor consumes and how much energy the battery bank can store. Some hybrid boats solve the problem with a diesel-electric generator. New lithium battery technologies are constantly improving, so the day will undoubtedly come when you can get a sailboat to run on nothing but electricity.
The question will always be, what do you want from your sailboat motor? This goes back to the original question, why do sailboats have motors? If you believe it’s there to get you on and off the dock—and not much else—then an electric engine with a moderate battery bank is more than adequate. If, however, you want to motor into the wind for hours or travel on no-wind days, you’d likely be very limited by an electric-only sailboat.
There are also electric outboard motors, but these are generally smaller and not yet appropriate for cruising sailboats. Further, they share the same problems and limitations as a gas outboard motor, so the benefits are limited.
Maximum Hull Speed and Beyond
Does a sailboat have a motor? As you can see, the answer is generally yes. But there are some historic vessels out there, like replica galleons and schooners built over 100 years ago, that do not and never did have engines.
Intrepid travelers like Lin and Larry Pardy have circumnavigated the globe multiple times in engineless vessels. Not having a motor keeps the boat simple and makes cruising more affordable.
Does your sailboat need a motor? That’s a question only you can ask. As a beginner, maneuvering under sail alone can be intimidating. A motor allows you to bail when the sailing is no good and will probably enable you to enjoy sailing and boating more often. In the end, the choice is yours.
Sailboat Motor FAQs
Do all sailboats have a motor?
It depends on the type of sailboat. Small sailing dinghies that you can easily row do not usually have motors. But most cruising and racing sailboats do, simply because it enables the boat to be docked easily. A motor can also keep the boat moving when the wind is calm. In some conditions, it can also help the sails work by motor sailing.
How are sailboats powered?
Sailboats, by definition, are powered by the wind. Nonetheless, most sailboats you see today also have motors. These are called auxiliary engines because the engines are not the primary means of propulsion. Instead, the boat is designed to sail—but when it can’t for some reason, it motors as a powerboat would.
