Top Reasons Boats Have Multiple Outboard Motors

March 8th, 2019 by



Boats can have inboard, outboard, or stern drive motors. These engines service a variety of purposes and come with different benefits and challenges. Below is a breakdown of the styles of engines and benefits of running multiple outboard motors.


Inboard motors are set up inside the boat, and the prop and rudders are set up into the hull. There are of two types of inboard motors – D-drive motors and V-drive motors. D-drive motors are set up in the middle of the boat used in ski boats. A V-drive motor is set up under the transom seating and is meant for watersports, especially where the person is behind the boat.


Outboard motors are set up outside the boat on the transom. Fishing boats and light commercial boats are primary users of outboard motors. Outboard motors are easy to maintain when compared to inboard motors because of their positioning. They also maximize the usable space inside the boat.


Sterndrive motors, also knowns as inboard/outboard motors (I/O motors), have their engine attached inside the boat but the second half is an outbound. Sterndrives were popular before outbound motor sales overtook inbound sales. These motors are ideal if the boat frequently navigates shallow waters.

Fitting with outboard propellers usually involves rigging the boat with multiple motors. There is a raging argument within the boating community on a single outbound motor VS multiple outbound motors.

Single motors are traditionally preferred, and there are several compelling arguments in favor of them. However, multiple outbounds have rapidly gained popularity. Advancing technology is solving common drawbacks like excess weight, higher surface area, and increased drag.

Irrespective of which camp is correct, it is a fact that multiple outbound motors are in fashion. Here are some top reasons why boats have multiple outboard motors.


Hole Shot Speed 

Multiple outbound motor installations provide higher horsepower. A hull fitted with a 1000 horsepower is much faster than a hull with 750 horsepower. This setup, however, comes with a problem of increased drag due to a higher surface area.

Modern motors are lighter than their counterparts a few decades ago. They are also significantly smaller. These days, there is little worry about extra weight and drag when upgrading to multiple outbound motors.

In a holeshot test, a twin 150 horsepower motor achieved an acceleration to 30kmph in 5.5 seconds. A single 250 horsepower motor reached the same acceleration in approximately 8 seconds. You can expect a 6-10mph increase in top speed with every additional outbound motor.

Speed also depends on how many strokes the motor has. A two-stroke motor has an impressive acceleration and hole shot speed. These days, four-stroke motors have overtaken a two-stroke engine’s speed advantage. Acceleration time from idle to full throttle mode in a four-stroke engine is significantly better. They also reduce torque.


Speeding Vs Trolling

High-end fishing tests speed as well as skill. The ability to reach the fishing area quickly is one factor of success. The other is the skill of being quiet and not scare away the fish.

Most boats are fitted with a powerful outboard (or multiple outboards) to accelerate to the fishing spot. After reaching the fishing spot, they switch to the smaller lower power engine for low noise levels. Trolling of fish needs low noise levels.

Trolling is a fishing method where the boat moves slowly and quietly with a bait attached to is back. The bait is used to attracts predatory fish. Trolling needs control of speed and noise levels.

A low power outboard makes much less noise at low speed when compared to a high-power outboard that runs at idle speed. Moreover, if a high-power outboard is kept idle for many hours, may damage the motor. Many anglers also use kicker motors for trolling to keep costs low.


Fishing Tournaments

Fishing competitions need specific set up depending on the event. The popularity of the sport attracts professional participants who have endorsements from big brands.

These fishing tournaments need specialized boats with multiple motors to perform specific actions. Additional outboard motors are added to achieve top-speed to reach a fishing honey spot. Outbounds are a popular choice because of their high horsepower and smaller size.


Dinghy Setup

There is another reason why boats have multiple outbound motors – to allow the use of an inflatable dinghy. Sometimes, an additional outboard motor is attached to allow the use of an inflatable dinghy. Large boats have at least two engines attached to them – a large one to operate the boat and smaller one to operate a dinghy.

Since outbounds hang from the transom, it is easy to carry an inflatable dinghy along and attach a motor to it. The inflatable dinghy can be put to use when the board is anchored, or when there is an unexpected disaster.


Back-up Motor

When going deep into the ocean, it can be a bit dangerous to depend only on one motor. Multiple motors ensure that there is a wing motor in case of a breakdown.

Outbound motors are efficient and good looking. However, they are also less reliable when compared to inboard motors. It is safer to have a backup when venturing deep into the ocean.


Navigating Tides

Strong tidal currents in the sea are more common than you think. A basic rule of boating in the rough sea is to make the tide not work against you. However, it is not possible to manage this all the time. Multiple outbound motors come in handy when it is necessary to climb a strong tide.

Anglers frequently get caught in rough weather situations in spite of sophisticated weather predictions. Electrical storms can be particularly dangerous during a long-range boating ride.

When caught in one, there is only one strategy to follow – get out of that place as soon as you can. Having multiple powerful motors makes it easy to speed to the coast.


Turns Heads

Modern motors 6-10 times more powerful when compared to the ones built in the1960s. In spite of that multiple outboard motors, sometimes as many as 9, on an expensive boat has become a fashion statement. A few years ago, such a set up would have turned heads. Today multiple outboard motors is a common sight at the docks.

The real beauties in any boat show are the luxury boats with many outbound motors. Some even have well over a couple of thousand horsepower hanging from the transom. The set up always turns heads in spite of overpowering the boat.

There is a debate on the torque and the utilization of the power of each motor when positioned so close to each other.  The set-up may not get enough bite of the water.  The cumulative weight may also make the boat unstable.

More outboard motors on a boat represent more horsepower. More horsepower is attractive. This is another simple reason many expensive boats opt for a large number of outboards as a way of making a statement.


How Many Outboard Motors are Too Many?

The government decides an approved maximum horsepower for different boats. Exceeding this number can be dangerous. Outbound motor manufacturers actively advertise multiple motors. This strategy allows them to sell more units. Higher sales generate high revenue as the motor cost is expensive.

Overpowering a boat by adding too many outboard motors can even be illegal. There are strict laws that the federal government and states clearly define. Breaking these laws will attract fines and other penalties. If there is damage done due to an accident, it may result in expensive lawsuits.

Overpowering will impact insurance coverage of the boat. Going above the recommended horsepower can make the insurance company deny insurance altogether. If approved, more horsepower attracts a higher premium.


Most Popular Outboard Brands 

With the rising popularity of multiple outboard motors, big brands are competing in this space.

Mercury Marine builds its motors with a focus on reducing friction during holeshot acceleration. Yamaha Outboards excels in manufacturing high-efficiency motors and four-stroke outboard motor and is known for its continuous innovations.

Evinrude Outboards are known for best in class performance and warranty. Using the direct injection oiling system they get peak performance while keeping fuel economy maximized.


Outboards are Here to Stay

Customizing a boat with multiple outboard motors is an expensive choice. However, outboards are here to stay. Their weight to size ratio is the best among all options available.

A 300 horsepower four-stroke outboard engine weighs approximately 620 pounds. A similar horsepower sterndrive weighs close to 900 pounds. If you add an extra light-weight engine to the outboard, you only add 90 pounds but add over 300 horsepower to the system.

Efficiency used to be a problem with multiple outboards, but that is no longer the case. Motor efficiency is directly related to its weight. As the manufacturers make the motors lighter, they become more efficient.

There is also a lot of effort in making the outboards look sleek. This increases the appeal to buy these units.

There is a lot of effort manufacturers put into making the outboards look sleek. Good looks of the motors make multiple outboard set-ups attractive.

Contact us today and speak to our outboard motor specialists or take advantage of our online finance application to get pre-approved.

Posted in Boating, Safety, Summer