Choosing the Right Prop

Choosing the Right Prop

From its Oshkosh, Wisconsin, testing facility Merc offered us the use of a 1,900-pound Key West 2020 center-console rigged with a Mercury 150 FourStroke outboard, and a full complement of data acquisition gear. We tested each prop “light” (just the tech on board) and “heavy” (with 350 additional pounds in the boat), always with the 60-gallon fuel tank full.

Choosing the Right Prop

Black Max
$183.13
Aluminum, three-blade, 15" x 17" Top Speed/Light: 41.9 mph @ 5,766 rpm
Top Speed/Heavy: 41.8 mph @ 5,820 rpm
0-to-20 mph/Light: 3.4 seconds
0-to-20 mph/Heavy: 4.3 seconds
Max economy: 6.09 mpg @ 3,250 rpm/22.0 mph

Choosing the Right Prop

Tempest Plus
$610.30
Stainless steel, three blade, 14 5/8" x 17" Top Speed/Light: 45.9 mph @ 5,779 rpm
Top Speed/Heavy: 43.5 mph @ 5,534 rpm
0-to-20 mph/Light: 3.8 seconds
0-to-20 mph/Heavy: 4.6 seconds
Max economy: 5.80 mpg @ 3,253 rpm/23.7 mph

Choosing the Right Prop

Revolution 4
$691.90
Stainless steel, four blade, 14 5/8" x 17" Top Speed/Light: 41.9 mph @ 5,766 rpm
Top Speed/Heavy: 41.8 mph @ 5,820 rpm
0-to-20 mph/Light: 3.4 seconds
0-to-20 mph/Heavy: 4.3 seconds
Max economy: 6.09 mpg @ 3,250 rpm/22.0 mph
Boating Magazine

Choosing the Right Prop

**Enertia **
$691.90
Stainless steel, three blade, 14 7/8" x 16" Top Speed/Light: 44.9 mph @ 5,812 rpm
Top Speed/Heavy: 43.0 mph @ 5,778 rpm
0-to-20 mph/Light: 3.5 seconds
0-to-20 mph/Heavy: 3.9 seconds
Max economy: 6.07 mpg @ 3,251 rpm/22.4 mph
Boating Magazine

Choosing the Right Prop

Enertia
$691.90
Stainless steel, three blade, 14 5/8" x 17" Top Speed/Light: 46.4 mph @ 5,791 rpm
Top Speed/Heavy: 43.9 mph @ 5,656 rpm
0-to-20 mph/Light: 3.6 seconds
0-to-20 mph/Heavy: 4.5 seconds
Max economy: 6.12 mpg @ 3,248 rpm/23.4 mph

Choosing the Right Prop

**Enertia **
$691.90
Stainless steel, three blade, 14 1/2" x 18" Top Speed/Light: 46.5 mph @ 5,532 rpm
Top Speed/Heavy: 44.2 mph @ 5,446 rpm
0-to-20 mph/Light: 4.1 seconds
0-to-20 mph/Heavy: 4.8 seconds
Max economy: 5.72 mpg @ 3,258 rpm/23.7 mph

Choosing the Right Prop

Mercury SpitFire
The Mercury SpitFire is a new four-blade aluminum propeller that promises to deliver better acceleration and handling than the Black Max. At the time of our test, the SpitFire was available only for Mercury 25- to 125-horsepower outboards, but a SpitFire model to match the gear cases of the MerCruiser Alpha One sterndrive and Mercury 150 FourStroke outboard will reach dealers in December, priced at about $200. Mercury says the SpitFire is a cutting-edge design and the most aggressive aluminum prop it's ever offered, with lots of blade cup and rake for strong acceleration and hull lift.

Choosing the Right Prop

Flo-Torq Hub
You don't have to own a Mercury engine to run a Mercury prop. The Flo-Torq II hub system is available with interchangeable inserts to match the prop-shaft size and spline pattern of many other outboards and sterndrives. The key to the Flo-Torq II system is a Delrin sleeve that mates to the prop shaft. The prop fits over the sleeve, secured by an adaptor and a prop nut. Upon hard impact, the Delrin breaks away and protects the drive from damage, in which case you simply replace the sleeve. Mercury says its Flo-Torq II system also better resists the higher exhaust temperatures of four-stroke outboards, which can degrade the rubber hubs used on traditional propellers.

Choosing the Right Prop

Find a dealer that will let you test-drive a number of props before you buy. You can do your own testing with a GPS and a stopwatch, but also pay attention to how the boat feels with each prop.