There is no shortage of motors for boats nowadays. All kinds of jet engines or outboard motor units are available for purchase, each offering a unique set of benefits and uses.
A particularly hot topic is the sterndrive vs inboard debate. Both motor types are very commonly used in boats, but which one is better? Is there even a better option at all? Well, these are the kinds of questions we are going to give an answer to today.
What is an inboard motor?
An inboard motor, as its name suggests, is a motor that is placed inside the hull, usually closer to its middle. The motor is connected to a transmission, which in its turn is connected to a propeller outside the boat.
Boats with inboard motors turn using a rudder which is controlled by a steering wheel. Thus, such boats have distinct mechanisms for propulsion and turning.
In some specialized boats, the inboard motor is placed closer to the stern. Such a design is very commonly seen in boats made for watersports like wakeboard, wakesurf, kneeboard, and many others.
What is a sterndrive motor?
A sterndrive motor is a motor that is attached outside the back of the boat. Unlike inboard motors, sterndrive motors include and the transmission in them the motor. Aside from that, boats with sterndrive motors are maneuvered with the entire drive turning in the desired direction.
Sterndrive vs inboard motors
There are many arguments for and against with both inboard and sterndrive motors. And since either type of boat motors has its advantages and disadvantages, we can’t say that one of them is clearly better than the other. Which one is going to be better for you will depend on your needs, as well as the water conditions you will be boating in.
Pros of inboard motors
Here are the advantages of inboard motors:
- Compared to a sterndrive motor that is all the way down, inboard motors tend to draw less fuel.
- In case of an accident, an inboard motor unit is less likely to be damaged since it is inside the hull. Typically, only the bottom parts of a boat’s propulsion system get damaged, and those are relatively cheap to repair.
- Boats with inboard motors are generally more stable and easier to control because their center of gravity is shifted more towards the center.
- Inboard motors, being in the hull of a boat, are completely safe from the corrosive effects of saltwater.
- Inboard motor units tend to require less maintenance. This is a consequence of the motor’s positioning inside the hull: it is less likely to get damaged in an accident, and it is out of the water and thus is safeguarded from the effects of sea salt, as we mentioned above.
Pros of sterndrive motors
The advantages of sterndrive motors are the following:
- Sterndrive motors tend to provide more propulsion to a boat than an inboard motor with the same horsepower. Furthermore, sterndrive motors are going to go faster at any given RPM, due to which they tend to use noticeably less fuel.
- The drive of a sterndrive motor can be tilted up and down (trimmed up or down). When in a higher position, the drive provides less propulsion, but it draws less fuel. In addition, when the motor is trimmed up, it allows traversing shallower waters.
- There are more replacement parts for sterndrive motors than for inboard motors. Thus, getting a damaged sterndrive motor up and running requires less time.
- Sterndrive drive boats have more free space inside because their hull isn’t occupied by bulky inboard motors. This allows for more storage space, as well as for a more variety of seating positions.
- Sterndrive motor boats tend to be more maneuverable than inboard units.
- Boats with sterndrive motors tend to have V-shaped hulls, which makes them run better in rough waters.
- When going in reverse, a sterndrive motor allows you to change the direction you are going in.
- It is much easier to access all the components of a sterndrive motor than in an inboard engine.
Cons of inboard motors
Essentially, the cons of inboard motors more or less mirror the pros of sterndrive motors. But you don’t have to figure out the downsides of inboard motors yourself since we’re going to provide you with a ready list:
- Inboard motors consume more fuel and deliver less propulsion than sterndrive units.
- Boats with inboard motors don’t have as much interior space left. This downside is going to be much more noticeable in smaller boats.
- There tend to be fewer replacement parts available for inboard motor units.
- Even though inboard motor boats are stable, they are noticeably less maneuverable than sterndrive boats. This is going to be especially felt in small water bodies.
- You can’t really control the direction of the reverse gear in a boat with an inboard motor.
- Some of an inboard motor’s components are away from view. This makes maintenance more difficult, especially while on the water.
Cons of sterndrive motors
- Since sterndrive motors are entirely outside a boat’s hull, they are more likely to be damaged in shallow waters.
- Sterndrive motor boats are less stable than inboard motor boats.
- Saltwater or brackish water are going to have a corrosive effect on the exposed sterndrive motors. Due to this, sterndrive motors require regular maintenance.
What about safety?
Safety is another hot topic in the sterndrive vs inboard debate. It is a common point of view that sterndrive motors are more dangerous than inboards because their propeller isn’t hidden beneath the hull.
While it indeed is true that sterndrive motors’ propellers pose an increased risk of injury, they aren’t as dangerous as some people portray them. When the drive is fully down and submerged into the water, you can’t accidentally injure yourself by, for example, sticking out your arm too far.
So as long as you are careful and follow safety procedures, you should be okay.
On the other hand, you can indeed get injured if you fall out of the boat right into the motor, so there’s a certain degree of carefulness that you need to maintain. This also applies to driving your boat with the drive trimmed up.
Sterndrive motors can pose a danger if you’ve got pets or children with you. In a boat with a sterndrive motor, you would need to keep an eye on your companions all the time. Or if you don’t want to deal with any propellers that are more or less exposed, you need to go for an inboard motor.
Inboard motor units are definitely safer than sterndrive motors. It is very unlikely for you to come in contact with the propeller since it is hidden beneath the boat’s hull. There is a risk, but it is basically non-existent compared to sterndrive motors.
Who should go for an inboard motor unit?
Given the advantages and disadvantages mentioned above, we think that an inboard motor would be more suitable in boats that will be traversing larger water bodies where maneuverability isn’t as big of a concern. In addition, due to their higher stability, inboard motors may be a more plausible choice for boats that will be carrying a lot of cargo.
Inboard motor boats can also be driven in any kind of water without direct exposure to salt and other elements. Their hull and turning components may still require maintenance in saltwater, but the most complex and expensive component – the motor – is going to be safe from its effects.
Aside from that, inboard motors are very frequently used in specialized ski and wake boats, but these aren’t boats that the general consumer should go after since they are specifically designed to perform well in their discipline.
Who should go for a sterndrive motor unit?
We’d say that sterndrive motors are going to be more suitable for boats that are going to traverse small and cramped water bodies. In such areas, the maneuverability and the better reverse are going to really come in handy.
Plus, a sterndrive motor may be a more reasonable choice for a small boat. In a smaller boat, the area occupied by an indoor motor is going to be bigger relative to the area of the boat. So if a free room is important to you, go for a sterndrive motor.
When it comes to water conditions, things are a little more difficult with sterndrive motors. If you don’t mind doing more or less often maintenance, then you can drive a sterndrive motorboat in any kind of water. But if you don’t wish to waste too much time on maintenance, then you can either get a sterndrive motor and drive your boat only in freshwater (though it will still require maintenance), or go for an inboard motor and drive it in any water.
As we’ve mentioned at the beginning, it isn’t possible to say that one kind of a boat motor is clearly better than the other. There are many factors in play which need to be considered by you when trying to pick a motor for your boat.
And hopefully, the pros and cons we’ve overviewed are going to provide you with a good idea of where and in what applications each type of boat motor is going to work well.