Why change props?

Subman95

Cadet
Joined
Jun 16, 2014
Messages
6
After years of using my parents boat or my in-laws boat I finally had to purchase my own. I hear people talking about new props every two years. Why? Do the splines wear out? My boat is a 27 ft. With 454 bravo 3. Any info on this would be great. Thx
 

KYsean

Seaman Apprentice
Joined
Jan 7, 2012
Messages
47
Aluminum props wear out, get dinged and bent. SS props will last a lot longer with normal use and no run in's with rocks and stumps. Peoples needs also change as in a normal boat load increases or decreases for a season, people may start water sports they didn't before. Maybe they realized from forums like this that they did not have the correct prop from the start to get good RPM's at WOT. Lot's of good reasons to change a prop.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
As long as you do not hit anything with the prop, even an aluminum prop will last years. Hitting sand or rocks, or even silt and mud will wear out an aluminum prop pretty easy.

That big block motor of yours can overload the prop, causing the prop hub to spin, so I would recommend you carry a spare prop, and take it easy on the throttle, to minimize the change in torque transferred to the prop.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
While an al prop will wear over time I see no reason to change props if there hasn't been any unfortunate accidents.
If you operate in salt more frequent replacement may be necessary.
Fresh water operation I think 20 years would be reasonable assuming you haven't struck anything.
After 20 years a change may be needed just to access more modern technology.
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Regarding the big block, it runs thru a Bravo3 which is a dual prop setup. I am sure that drive and props are not stressed about it.

Changing props every 2 years? Never heard that one. Impellers every two years, sure, and to replace those in an Alpha drive you remove the lower and that is easier to do by removing the prop first, especially if it is stainless as those are heavy, maybe some terminology is getting mixed up in translation. On a Bravo the raw water pump is on the front of the engine, no need to split the drive.

It is a good thing to remove the props each year, and re-grease the prop shaft splines to eliminate the chance of props siezing to the shaft, but even then if greased on the last install then 2-3-or even 5 years maybe good enough but I would not recommend waiting that long.

If you boat in the ocean or salt water anywhere really, and the boat is left in the water for weeks at a time. you need some type of galvanic protection to keep the dissimilar metals in the drive/props from corroding and losing material when they try in essence to make a single cell battery. Two types of metal in salt water when close enough will generate a small electric current, when this happens one metal gives up material and one takes it on, but neither in a good way. Have to replace anodes often, anodes are mounted on the drive or drive mounts and give up their material "earlier" thereby protecting the stuff that is important to not have corrode away on you. There are active electrically powered solutions that counteract this as well, your boat may or may not have this installed. If the props are in salt water and the corrosion protection has failed then they will usually not last a whole season if the boat is slipped all year. So, this can cause prop replacement being needed every season or two for sure, and the drive eventually.

For inland trailer boating, in my opinion good props, especially the SS ones on a Bravo3, should last as long as the engine and drive barring any prop strikes or corrosion issues.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
If you're pushing a heavy boat with an aggressive aluminum prop, run your slip numbers from time to time. You'll be surprised how worn out and "burnt" an aluminum prop can get in very short order.
 
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