Best Outdrives For Boats: A Comprehensive Guide

Choosing the best outdrive for a boat depends on several factors, including the size of the boat, the intended use, and personal preferences. Outdrives, also known as sterndrives, are popular choices for inboard-outboard power boats as they offer high performance and efficiency. Some of the well-known manufacturers in the sterndrive market are Ilmor, Volvo Penta, and Mercury Mercruiser. Each company offers a range of sterndrive models with different features and specifications to cater to various boat sizes and applications. When selecting an outdrive, it is essential to consider factors such as power requirements, fuel efficiency, corrosion resistance, and ease of maintenance. Additionally, the availability of parts and trained technicians for the specific sterndrive model should also be taken into account to ensure smooth and cost-effective repairs when needed.

MerCruiser Alpha One: a popular choice for its value, performance and speed

The MerCruiser Alpha One is a popular choice for those seeking value, performance and speed in their outdrive. Cited by Mercury Marine as "the most popular sterndrive in the world", the Alpha One is used for single or twin-engine applications.

The Alpha One has a sleek, hydrodynamic profile that slices through the water to enhance fuel economy and control. It's rated for speeds up to 65 mph and up to 300hp in single and dual applications. The hydrodynamic lower unit produces minimal drag, improving boat performance and fuel economy. The Alpha One also features a Tri-Paint System, creating a tough, durable corrosion-resistant barrier.

The MerCruiser Alpha One is designed with ease of maintenance in mind. It features an integrated water pump and permanently lubricated pivot points, reducing the time spent on maintenance. Routine drive lube checks are simple, with an easy-check drive lube monitor that allows you to check the level and quality of the lube from the engine compartment. An audible warning will alert you if the lube gets low.

The Alpha One also prioritises flexibility. It can accommodate 3, 4 or 5 blade propellers in aluminium or stainless steel. With a 15" diameter propeller, the Alpha One has a 300 HP (221 kW) maximum power capacity.

The MerCruiser Alpha One is a reliable and durable choice for boaters seeking a combination of value, performance and speed. Its efficient design, ease of maintenance and flexibility make it a popular option for those wanting a powerful yet budget-conscious outdrive system.

MerCruiser Bravo Series: an upgrade from the Alpha One, with a focus on high-speed performance

The MerCruiser Bravo Series sterndrives are an upgrade from the Alpha One and feature the latest innovations in boat outdrive performance. The Bravo 1, in particular, is designed with a focus on high-speed performance. It is an excellent choice for those seeking speed and versatility, as it can be used with single, twin, or triple engine applications.

The Bravo 1 sterndrive is a powerful option, capable of propelling gas engines up to 600 HP to speeds over 100 mph. This impressive speed is achieved through its exclusive performance torpedo design and dual water pickups, which also allow for seamless handling of both high and low speeds. The Bravo 1's torpedo design is key to its performance, ensuring smooth and efficient movement through the water. Additionally, its dual water pickups provide the necessary cooling for high-performance engines, contributing to its ability to maintain exceptional speeds.

Compared to the Alpha One, the Bravo 1 offers enhanced speed capabilities. The Alpha One has a maximum power capacity of 300 HP with a 15" diameter propeller, while the Bravo 1 can accommodate up to 600 HP. This makes the Bravo 1 a more powerful option for those seeking higher speeds and greater engine compatibility.

Another advantage of the Bravo 1 is its ability to handle a wide range of propeller configurations. It can accommodate 3, 4, or 5 blade propellers in either aluminum or stainless steel, providing users with flexibility in their propeller choices. This versatility allows users to optimize their boat's performance based on their specific needs and preferences.

In summary, the MerCruiser Bravo Series, including the Bravo 1, is a notable upgrade from the Alpha One, offering high-speed performance, innovative features, and versatility in engine and propeller configurations. The Bravo 1's focus on speed, powerful performance, and adaptability makes it a top choice for boaters seeking an advanced and dynamic outdrive system.

Volvo Penta: lightweight, fuel-efficient and made from aluminium

When it comes to choosing the best outdrive for a boat, there are several factors to consider, including performance, fuel efficiency, and ease of maintenance. One of the most renowned brands in the boating industry, Volvo Penta, offers a range of outdrives that stand out for their lightweight construction, fuel efficiency, and aluminium composition.

Volvo Penta outdrives are known for their lightweight design, which not only improves the boat's overall performance but also enhances fuel efficiency. By reducing the overall weight of the boat, these outdrives contribute to better acceleration, higher top speeds, and optimised fuel consumption. This weight advantage is particularly beneficial for boats in the 20–45-foot range, where every pound counts.

In addition to their lightweight construction, Volvo Penta outdrives are crafted from aluminium, a material known for its durability and corrosion resistance. Aluminium is a lightweight metal that provides strength and rigidity to the outdrive, ensuring reliable performance even in challenging marine environments. Its corrosion-resistant properties are especially advantageous in saltwater conditions, where saltwater spray and submersion can lead to rapid deterioration of metal components.

The fuel efficiency of Volvo Penta outdrives is another standout feature. With their advanced engine technology, these outdrives deliver superior power-to-weight ratios, resulting in increased torque and acceleration. The next-generation V6 and V8 engines offer unparalleled fuel economy, ensuring that your boat travels further on less fuel. This not only saves you money on fuel costs but also reduces your boat's environmental footprint, making it a more sustainable choice.

Volvo Penta's commitment to innovation is evident in their Duoprop technology. The Duoprop system features twin counter-rotating propellers that provide several advantages over conventional single-propeller setups. With Duoprop, energy losses are minimised, allowing boats to maintain planing at lower revolutions per minute. This directly translates to reduced fuel consumption, making Volvo Penta outdrives an economical choice for boat owners.

In addition, the Duoprop system offers improved handling, exceptional straight tracking, and reduced roll. The twin counter-rotating propellers distribute shock pulses over more blades, resulting in lower vibration and noise levels. This enhances the overall comfort of your boating experience, making it more enjoyable for you and your passengers.

When it comes to maintenance, Volvo Penta outdrives are designed with ease of service in mind. The company offers a wide range of service centres and trained technicians, ensuring that you can access the necessary support for your outdrive. Additionally, the availability of parts for Volvo Penta outdrives is generally good, although some models may have parts that are easier to source than others.

In conclusion, Volvo Penta outdrives are an excellent choice for boat owners seeking a lightweight, fuel-efficient, and aluminium-constructed option. With their advanced engine technology, innovative Duoprop system, and commitment to durability and performance, Volvo Penta outdrives deliver an exceptional boating experience. Whether you're an avid boater or a leisure enthusiast, Volvo Penta outdrives are worth considering for your vessel.

Ilmor One Drive: a smooth-shifting system with a 5-year/500-hour factory-backed warranty

Ilmor's One-Drive® sterndrive system is a smooth-shifting system that makes manoeuvring your boat quiet and easy. The system sets the standard for sterndrive propulsion in the recreational bowrider and cruiser markets. The One-Drive® is offered with electronic throttle and closed cooling systems as standard, including the uniquely closed-cooled exhaust manifolds.

The Ilmor One-Drive comes with a 5-year/480-hour standard limited warranty. The sterndrive is powered by Ilmor's line-up of recreational marine engines, including the 5.3L GDI-S, 6.0L MPI-S, 6.2L GDI-S, and 7.4L MPI-S engines. The engines are based on the GM Marine LS “Gen IV” V-8, with an aluminium block (for the 6.2) and heads, port fuel injection, closed cooling, new down-tube exhaust manifolds, power steering, and a new intake manifold designed to deliver stronger midrange power.

The One-Drive® system is ideal for recreational boating of all kinds, and the Ilmor MPI-S, and GDI-S engines are built to the same standards as their world-renowned race engines. The One-Drive® can be paired with the optional One-Touch® joystick in twin applications, offering a refined ride and greater manoeuvrability for a smooth and confident experience on the water.

The central differentiator of the 'One Drive' propulsion system is the electro-magnetically actuated hydraulic clutch transmission, which provides a smooth and quiet shift, akin to luxury road cars. The hydraulic clutch system quietly engages and disengages gears at an incredibly responsive two-shifts-per-second. The twin-propeller drive unit is built with precision-forged gears for increased durability and is hard anodized for superior corrosion protection.

Arneson M6 M8: a good choice for high-power engines

Arneson M6 and M8 outdrives are a good choice for high-power engines. The M6 and M8 are part of a range of surface-piercing propeller drives, which are designed to reduce underwater drag by 50% compared to conventional propulsion systems. This means that boats can go faster at the same engine RPM, improving fuel mileage.

Arneson surface drives are well-known and were developed by Howard Arneson, who also invented the automatic swimming pool vacuuming system. Arneson first tested the prototype on racing catamarans. Today, Arneson drives are popular for use on high-performance catamarans and V-bottoms, and larger versions are used on performance yachts.

The M6 and M8 are designed for engines rated at 700 hp or more. They are part of the Mercury Racing range, which also includes the Dry Sump Six and NXT. Mercury Racing also built a surface drive with twin counter-rotating propellers called the Blackhawk in the early 1990s.

Arneson surface drives have very few moving parts, which means there are fewer things that can go wrong. This also means lower maintenance, with typical maintenance involving 200-hour oil changes and electrolysis anode replacements.

Frequently asked questions