Sea Trials: Power to the Props, Music to the Ears

The power-to-weight ratio of Mercury’s 5.7L V10 Verado outboards stands out right away: These are 350- and 400-horsepower engines weighing as little as 695 pounds. I’ll spare you the math but encourage you to look around and reflect on that.

They’ve a small footprint, too, mounting down to 26-inch centers, if called for.

Performance? Oh yes. High displacement, quad-cam design; torque-optimized spark timing; performance-tuned intakes and a Revolution X propeller engineered for the package promise gratifying low-end power and high-end performance.

This unique combination suggests installation options for a variety of fishing boats, from singles on large hybrid bay boats to multi-power options for the biggest center consoles.

We put three 400-hp V10 Verado outboards through unique fishing applications during filming of our Florida Sportsman Sea Trials episode. Two 25-inch shafts and a 30-inch center were mounted on a Contender 39ST. The 39ST is a step-hull center console that’s basically the Platonic ideal of the modern Florida bluewater fishing vessel.

Conditions were hardly Platonic for speed and fuel economy testing. We had south winds of 20 knots, heavy outgoing tide, close-interval chop and a nearly full fuel load. Top protected-water speed I saw was 68 mph. I’m betting it could top 70 (Jordan DeLong, from Contender, agrees).

What all else did we find out?

Well, I may have had some mild wind burn at the end of the day—but significantly, my ears were not ringing.

The Mercury team out of Fond Du Lac, Wisconsin, prides itself—justifiably—on developing not just raw power but also the user interface. The engineers know there are people to take care of.

Take noise management, for instance. For such a powerful package, the V10 Verado is surprisingly quiet. The 5.7L V10 benefits from multi-chamber air intake, fuel injector covers, and sound-dampening cowl. The company promotes that the engine is up to 56-percent quieter at wide-open throttle and up to 42-percent quieter at cruising speed than competitors. How does this translate for a triple engine setup on a big center console?

Using a NIOSH Sound Level Meter on my iPhone, the highest sound level I picked up was 94 dB at WOT, 6,300 rpm, at 64 mph. This I measured in the cockpit from behind the leaning post. At a comfortable cruising speed, 3,800 rpm and 40 mph, the sound level was 86-88 dB. Idle speed was whisper-quiet, 58 dB. At the helm, conversation was never a problem at any speed. I don’t have a NIOSH record of other manufacturers’ engines on the 39ST, but based on my experiences with other installations over the years, i can assure you: It can get louder.

For perspective, I do have some calibration data. The day before our Sea Trials, I checked my own single-engine center console with the Sound Level Meter. From my Suzuki DF175, at my helm, I picked up 89 dB at WOT, 5,500 rpm, which yielded 43 mph. A comfortable cruise on my boat produced 81 dB at 30 mph. Idle speed: 57 dB. All this is to say, the triple array of 400-hp Verado outboards was as quiet, even quieter(!), at comparable speeds, than my 175-hp single-engine rig.

Best efficiency I saw on the Contender 39ST Mercury gauge was 1 mpg even, at 40 mph. At WOT, it dropped to .6 mpg. That’s about what I expected of three high horsepower engines on a 15,000-pound boat loaded with just shy of 400 gallons of fuel. Worth noting is the 5.7L V10 is designed for optimal performance on 87 octane fuel—the regular stuff.

Mercury built efficiency-enhancing technology, advanced range optimization, into the powerplant in the form of post-O2 sensors to adjust and optimize fuel delivery for maximum cruising efficiency.

The fuel-saving benefit of reduced weight is also evident. One would infer that shaving hundreds of pounds off the transom would contribute to an improvement in hole shot.

The big Contender maybe isn’t the best test-subject for hole shot—by design it’s a level-riding boat, exhibiting very little bow-rise. I didn’t take a formal timing of “hole shot” for this reason: The 39ST with 400-hp Verado outboards was laughably quick—the fun kind of laughter. Within 5 or 6 boat lengths we were passing 40 mph. Some boats feel as if they’re struggling to break away from the weight of their own powerplants. Not. This. One.

On the fishing grounds, all kinds of features bring smiles: Vibration-dampening advanced mid-section, electric steering, confidence-building 150-amp alternator. Mercury offers useful “autopilot” type stuff in the Verado engines through Joystick Piloting. In our Sea Trials video segments, we fished through Skyhook (holding position and heading, a virtual anchor), Bowhook (hold while allowing the heading to drift naturally) and Drifthook (maintain heading while letting the boat drift).

In fact, we did all kinds of stuff we normally do when we’re fishing—including catching a few fish. Tune in and watch!

Mercury 5.7L V10 Verado Specs




• Horsepower: 350/400
• Weight: 695 lbs (lightest model)
• Alternator: 150 amp
• Shaft Lengths: 20"/25"/30"/35"
• Colors: Black, Cold Fusion White, Warm Fusion White, Pearl Fusion White
• Rec. Fuel: 87 Octane
• MSRP: $42,630 (25" 400XL White)

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This article was featured in the March 2025 issue of Florida Sportsman magazine. Click to subscribe