‘Power Option Shootout’
By Pacific Powerboat Magazine

Article Courtesy of Pacific Powerboat Magazine

One boat model – three engine options. With special thanks to the Tristram Marine Team – who supplied us with three Tristram 821 Offshore models, each powered by a different propulsion option – we were able to get out on Auckland Harbour and report on a showdown between the MerCruiser 270hp 3.0L V6 Diesel Sterndrive, the Twin Mercury 250hp V8 Verado outboards, and the Single Yamaha 450hp V8 XTO outboard. Each setup offers distinct advantages, particularly in fuel efficiency, maintenance, and performance. After a day on Auckland Harbour, we discovered how these three compared against each other.

– BY DOUG DUKESON

270hp V6

Diesel Sterndrive

2 x 250hp V8

Twin Outboards

450hp V8

Single Outboard

MerCruiser 270hp 3.0L V6 Sterndrive Diesel

The MerCruiser 3.0L V6 Sterndrive Diesel engine is designed to balance power, efficiency, and reliability. This compact yet powerful V6 diesel engine delivers 270 horsepower and offers smooth cruising performance while maintaining fuel efficiency.

One of the standout features of this engine is its modern common-rail direct fuel injection system, which optimises fuel delivery for improved efficiency, lower emissions, and reduced operating costs. Combined with a turbocharged and aftercooled design, the engine ensures strong torque output across a broad RPM range, making it well-suited for leisure and commercial vessels.

The MerCruiser 3.0L V6 has improved engineering for quieter and refined operation on previous models, featuring advanced sound- dampening technologies that minimise noise and vibration. Its closed-loop cooling system enhances durability by preventing exposure to corrosive seawater, extending engine life and reducing maintenance requirements.

Power: 270 hp

Configuration: Single sterndrive diesel

Fuel Efficiency: Diesel engines typically excel in fuel efficiency, especially at mid-range RPMs, which is ideal for long-distance cruising.

Weight: Generally heavier than the outboard options, but the weight is centrally located, sometimes assisting stability.

Maintenance: Diesel engines are generally longer-lasting but require more intensive servicing.

Performance: Excellent low-end torque, making it ideal for heavy loads and rougher waters. However, it does lack the top-end speed of single and dual outboard configurations.

Ideal For: Offering torque for heavy loads, prioritizing fuel economy when travelling to distance fishing grounds and then trolling for many hours. Most of the Tristram Diesel sterndrives sold to date have been for fishing, where trolling fuel burn is an important consideration. From these figures, we can see an excellent range at low speeds; at a trolling speed of about 8.6 knots, the sterndrive can cover 499 nautical miles using less than one litre of diesel per nautical mile.

The MerCruiser sterndrive option also offers a clean transom and can be better suited for some hull designs.

Twin Mercury 250hp V8 Verado Outboards

The Mercury 250hp V8 Verado outboard engine is designed to balance power, efficiency, and smooth operation. Built around a 4.6L V8 powerhead, it provides strong acceleration and exceptional mid-range performance while maintaining the quiet, refined operation that the Verado range is known for.

One of the 250hp Verado’s standout features is its Advanced MidSection (AMS), which significantly reduces vibration and noise, ensuring a smoother and more comfortable ride. This makes it an excellent choice for boaters, as it provides a quiet and refined experience without sacrificing power.

The twin outboard 821 Offshore option can be spec’d with electric joystick steering. This feature will allow for ease of maneuvering into jetties. The joystick also features a spot lock option that will hold the vessel on the spot for deep drop fishing, adding to convenience and safety.

Designed for both performance and reliability, the 250hp Verado features dual overhead camshafts (DOHC) for increased efficiency and durability. It also boasts a lightweight design, ensuring an optimal power-to-weight ratio for improved fuel efficiency and top-end speed.

Whether used for offshore adventures, cruising, or fishing, the Mercury 250hp V8 Verado is a versatile, well-rounded outboard that offers a seamless blend of power, comfort, and innovation.

Power: 500 hp (combined)

Configuration: Twin outboards

Fuel Efficiency: Outboards are less fuel-efficient than diesel sterndrives, but advancements in Mercury Verado engines offer improved fuel economy.

Weight: This setup adds more weight to the stern, but it provides redundancy if one engine fails.

Maintenance: Outboards are easier to maintain than sterndrives, with more straightforward access and fewer components below deck.

Performance: The twin Verado setup offers high top-end speed and excellent handling, especially for sport-oriented boating and fast acceleration out of the hole.

Ideal For: Performance-oriented boaters prioritizing speed, easier maintenance and redundancy should you run into trouble.

Single Yamaha 450hp V8 XTO Outboard

Yamaha has introduced the XTO Offshore 450, an evolution of its flagship XTO 425, delivering enhanced performance and modern convenience. Retaining the robust 5.6L big block displacement and many features of its predecessor, the XTO 450 builds on an already impressive platform.

The Phase Angle Control Charging System is a key upgrade, providing three-phase, simultaneous charging that generates more net amps at low RPM. This is ideal for powering high-demand devices like gyro stabilisers and air conditioning systems.

Yamaha’s TotalTiltTM system adds to the engine’s usability, allowing faster and easier tilting with a simple double-press of the tilt button. Meanwhile, the cowling now features raised chrome graphics and refined panels, giving the engine a sleek, premium aesthetic.

Yamaha has introduced new propellers for different vessel types, including the XTO EC® Prop for heavy boats and a 27-inch pitch prop for lighter vessels seeking higher speeds.

The Yamaha 450hp engine can be optioned with the all-new Yamaha Helm Master. This new option features a single engine joystick, allowing for maintaining a position for fishing or even integrating into a bow thruster for ease of docking. The next Tristram 821 Offshore single engine currently in build has the Yamaha Helm Master/Bow thruster integration fitted.

The XTO Offshore 450 is the premium choice in Yamaha’s outboard line-up.

Power: 450 hp

Configuration: Single outboard

Fuel Efficiency: More fuel efficient at lower speeds than the twin outboard option and performs well at cruising speeds.

Weight: The single-engine setup is lighter than the Diesel Sterndrive and twin outboard configurations, allowing for less stern-heavy weight distribution.

Maintenance: Outboards are generally easy to maintain, and the Yamaha XTO is known for its reliability.

Performance: The high-power single outboard option was the lightest power option with great top-end speed of 48 knots.

Ideal For: Those looking for high speed in a lighter, more straightforward setup. Providing high power in a single unit can be preferable for some boat designs with a more straightforward, single- engine setup. The single-engine boarding platform on the Tristram 821 Offshore matched with the Yamaha 450hp is unique with large swim/ fishing platforms on either side of the engine. This added real estate makes for a generous area for many activities.

Conclusion – Horses for Courses…

What is weighted as a priority to one power boatie may differ from another – fuel burn versus performance is always a significant consideration. The fuel results from our day out were largely as expected: the sterndrive offered the best fuel economy, while the outboard options were less efficient – especially when factoring in the higher cost of petrol compared to diesel. However, as mentioned, it’s not always about fuel consumption; for some, performance, which the outboard options deliver, takes priority over economy.

With all the weights, fuel consumption, and performance figures considered, your choice between these setups ultimately depends on your boating requirements – whether it’s high-speed performance with the Mercury Verado twins, long-distance reliability and economy with the MerCruiser diesel, or a powerful, straightforward Yamaha XTO outboard.

One constant is that the more horsepower you have and the more you use it, the more fuel you will burn.

The final decision depends not only on which engine style best suits your hull design, as both outboard and sterndrive setups have their advantages, but also on the type of boating activity that fuels your passion. Boat ramp depths can also be a contributing factor to a purchase decision. The sterndrive will draw more than the outboard. Therefore, an outboard option could be a wise decision on shallow boat ramps. Whether it’s offshore fishing, cruising with a focus on economy, or high-speed water sports, this will determine the ideal power choice for your boating lifestyle.

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