Power To The People

New Mercury SpitFire X7 Prop Raises The Bar 
In Mid-Range Outboard Performance
X7-3
High-quality props are critical components in the quest for better boat performance, and Mercury Marine’s new four-blade SpitFire X7 boosts the firepower of mid-range outboards common on many fishing and multi-purpose boats.
“This is great news for owners of 75- to 115-horsepower outboards,” says veteran guide and noted freshwater expert Scott Glorvigen.
“Mercury’s new SpitFire X7 is the first prop designed for these engines that utilizes the company’s proprietary X7 Alloy, which is 30 percent stronger and four times more durable than conventional steel,” he adds.
Benefits in power, speed and handling abound.
“Let’s say you have a fish-and-ski boat like the Lund 1675 Crossover I ran this summer, which is a great all-around family boat rated for engines up to 115 horsepower,” Glorvigen begins.
“With a standard three-blade steel prop, the boat performs fine, especially on calm water with three people in the boat. But if you put four or more people in it and get into rough water, it can take a little while to get on plane.”
During Glorvigen’s extensive testing of the 1675 Crossover, he found that adding a four-blade SpitFire X7 takes hole-shot to new heights. “Four blades grab more water, giving you the ‘traction’ to get on plane fast, as well as keep your bow up in heavy seas,” he explains.

Glorvigen found the SpitFire X7 out-performed other three- and four-bladed props in power and handling.
Thanks to a combination of small-diameter yet aggressive blades, a flared hub and high progressive rake, the lightweight SpitFire X7 also boosts overall acceleration, top-end speed and handling beyond the realm of props traditionally available for mid-range outboards.
“The progressive rake gives you much better bite and more lift, so there’s less boat in the water,” he says. “Because you’re steering more from the transom, you enjoy a better ride, and the boat handles more like a sports car than a pickup truck.”
While three-blade props are known for better top-end speed, Glorvigen reports the four-blade SpitFire X7 actually outran the three-blade versions he tested. “Although three-blade props normally have the edge, the new SpitFire was actually faster,” he says.
The SpitFire X7 yielded higher top-end speed than comparable three-blade options.
“As a bonus, there is also less torque on the steering system, which means less feedback at the wheel,” he notes. “That’s a big plus because most 75- through 115-horsepower engines feature non-hydraulic, mechanical steering systems where the driver does the lion’s share of the work.”
In the end, Glorvigen was so impressed he says he’ll stick with the four-blade SpitFire X7 long after the test is over.
“For me, there’s no reason whatsoever to go back to three blades in any situation, because of what it does for overall performance in a wide range of conditions,” he says.
Glorvigen advises anyone who’d like to get more from their boat to check out the new SpitFires, too. “Upgrading props is the least-expensive investment you can make to take performance to a whole new level,” he says.
The Mercury SpitFire X7 is available in 15-, 17-, 19- and 21-inch pitch options, with plans to add a 13-inch version soon. For more information, visit Mercury Marine.
Scott
Check out this video for more on the Mercury SpitFire X7.
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