~~ Prop Sizes - Do they matter? ~~

[brianmerc]

When I bought my boat it came with 3 different size props. I know that a bigger prop can make the boat go faster (top speed), but does the size of the prop make a different when pulling a skier? What are some advantages when using a bigger prop vs. a smaller prop? If a skier weighs about 250lbs, should I use a bigger prop to pull him out of the water?

 

[JB]

Re: ~~ Prop Sizes - Do they matter? ~~

Different props are like different gears in your auto transmission, Brian.<br /><br />The best prop to use for a particular situation is the one which will allow the engine to reach, but not exceed, the upper end of it's operating range.<br /><br />Too long (in pitch) of a prop would be like driving up a parking ramp in top gear; the engine is "lugging". Too short a prop would allow the engine to over-rev at full throttle.<br /><br />Most of us select one prop for maximum safe rpm with a light load and use that. Some boaters switch to a shorter pitch prop for heavy loads and for pulling "shark bait".<br /><br />Good luck.

 

[coupedeville]

Re: ~~ Prop Sizes - Do they matter? ~~

Think of it as driving a vehicle with a manual transmission: You start off in first gear and it's easier to get the vehicle moving, but you can only go so fast without over-revving the engine, say 30 mph. If you start in second gear, you'll be able to go faster, say 50 mph, but getting the vehicle to start moving is a lot harder, the engine will lug, and wont want to accelerate quickly.<br />Small pitch/diameter prop = 1st gear.<br />Big pitch/diameter prop = 2nd gear.

 

[brianmerc]

Re: ~~ Prop Sizes - Do they matter? ~~

Really? so with a smaller prop, it would be easier to pull a skier out of the water, and the boat will have a slower top speed?... but with a bigger prop, it would be harder to pull a skier out of the water, but the boat will have more overall top speed? <br /><br />Sorry, I'm new to all of this.

 

[fast525]

Re: ~~ Prop Sizes - Do they matter? ~~

JB, <br />do you know how to calculate which size prop I would need for my boat . The boat is a 1953 Lone Star Admiral that weighs 215lbs. and my motor is a 1956 30 hp johnson . Any guesstimates?

 

[rickdb1boat]

Re: ~~ Prop Sizes - Do they matter? ~~

JHM,<br /> This is what Michigan wheel recommends:<br /><br /> Propeller Type: Outboard<br /> Manufacturer : EVINRUDE, JOHNSON<br /> HP / Model : 30 HP - PIN DRIVE<br /> Year : 1956<br /> Boat Size : 12'-14' BOATS - LIGHT LOADS<br /> Material : ALUMINUM<br /><br />Blades 3<br />Diameter & Pitch Rotation 10-3/8" X 14" <br />Part # 012026 MICHIGAN MATCH