Propellers

The goal in propeller selection is to determine what propeller style and size will maximize performance for your boat, while allowing your engine to operate in the recommended RPM range (optimized power band). The correct propeller will prevent the engine from over-revving, yet allow it to reach the preferred RPM where maximum horsepower, load carrying capacity and performance is produced. This mix may change depending on the users needs, boat, load, and engine. Elevation and environmental conditions also affect this computation.

When selecting a propeller it is important to first measure your intended use. If you normally run your boat with a fixed load you should select a propeller that delivers optimum RPM with that load. If you intend to run a heavy load in the fall, it is best to select a smaller pitch propeller or gearing so that you don't loose RPM and drop below your engine's preferred power band. If you intend to run in different climates and different elevations, propeller choices again will vary.

You can strive to get one propeller that does it all, or invest in a propeller for lighter loads and another for heavy.

Stock motors run best from 3800 to 4000 rpm. Black Death motors run best from 4000 to 4175 rpm, and the BPS mag engines run best in the 4400 to 4600 rpm range. Note: Mag engines are fitted with a 5100 RPM rev limiter and you can run these motors to this limit without question, however, best performance and engine life is achieved by operating the mag engines near 4600.

Many shortail motors like the Mud Buddy short tail series do not have a broad propeller selection, rather they rely on belt sprocket variations. Some mud motors like the Pro Drive have fixed gearing and the proper propeller selection is very important.

If you can change drive ratios, it is best to select a propeller and/or sprocket ratio combination that runs a bit slower with a new propeller so that the RPMs can increase as the propeller wears.

A one pitch change will result in a 250 to 350 rpm change.

When using these charts - select one pitch smaller prop, or one gear ratio smaller when running above 4000 foot elevation or when operating a larger than normal boat and load.

Short Tail Prop and Sprocket Selection Chart
Engine	Propeller	Sprocket Size	Gear Ratio	RPM
Mag7000	12 X 11	40 top / 46 bottom	1.15:1	4400 - 4600
Mag 6000	12 X 11	38/46	1.21:1	4400 - 4600
Mag 5500	12 X 11	38/47	1.24:1	4400 - 4600
Mag 5000	12 X 11	38/47	1.24:1	4400 - 4600
Mag 45	12 X 11	38/48	1.26:1	4400 - 4600
Black Death 5500	12 X 11	40/48	1.20:1	3900 - 4175
Black Death 4500	12 X 11	38/46	1.21:1	3900 - 4175
Stock 35	12 X 11	38/50	1.32:1	3800 - 4000
Stock 27	12 X 11	36/50	1.38:1	3800 - 4000
Stock 23	11X10 or 12X11	34/50	1.47:1	3800 - 4000
Stock 18	10 X 8	32/50	1.56:1	3800 - 4000
Stock 14	10 X 8	32/52	1.63:1	3800 - 4000

Super Longtail Prop Selection Chart
Engine	Propeller	Sprocket Size	Gear Ratio	RPM
Black Death 4500	11 X 10	34 top / 54 bottom	1.59:1	3900 - 4175
Stock 35	11 X 10	34/56	1.65:1	3900 - 4175
Stock 27	11 X 8	32/54	1.69:1	3800 - 4000
Stock 23	11 X 8	32/56	1.75:1	3800 - 4000

Long Tail Prop Selection Chart (3800 to 4000 RPM)
Engine	Propeller	Engine	Propeller
Mag45	10 X 8	Stock 18	9 X 5
Black Death 4500	10 X 8	Stock 14	8 X 4
Stock 35	10 X 6	Stock 12 Gear	10 X 8
Stock 27	9 X 7	Stock 13	8 X 4
Stock 25	9 X 7	Stock 9	7 X 4
Stock 24	9 X 6	Stock 6 Gear	9 X 7
Stock 23	9 X 5	Stock 6	6 X 4

 

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The BPS Tiger and Big Blade industry leading propellers feature unmatched durability. finish and balance. These time-proven propellers deliver limited slip and provide exceptional hole shots while crank out amazing top end speeds. Rockwell hardness from 30 to 37 ensures long life.

Big Blade is a trademark brand.