Which is better

[Adam76]

Hi everyone, new member and new boater here. My question is I have a 21' Cuddy cabin with a 350 5.7 Mercruiser, that came with two props. One is aluminum with a 19pitch and the other is stainless with a 17 pitch, which is better and what differences would there be between them. Thanks

 

[Bob_VT]

Re: Which is better

Welcome to iboats.

Best to start reading http://boatpropellers.iboats.com/propeller-tutorials/material/?*******=822535584

You should run the prop that affords you the best all around performance and optimum rpms.

 

[steelespike]

Re: Which is better

Generally a ss prop will out perform an al prop.
Give them both a test run paying close attention to hole shot and wot rpm and speed.
tests should be done with a light load.

 

[Adam76]

Re: Which is better

Ok thanks, I'm new to boating so I'll see if I can figure it out. what is the optimum rpms that I'm looking for?

 

[craze1cars]

Re: Which is better

Depends on the year/make/model of your engine.

Unless it has been removed and lost, you will find a sticker in your engine compartment that specifically provides you this spec/range. Probably says something like "4,200 to 4,600". I usually suggest targeting the higher end of that range....whatever the range for your motor is.

 

[Adam76]

Re: Which is better

Well I had it out yesterday with the Aluminum 19p prop, and it ran around 4,200 at around 36mph, what difference would I see by switching to the SS 17p, sorry newbie here. Optimal rpm's are 4,200-4,600. Thanks

 

[Scott Danforth]

Re: Which is better

my guess is one prop was for cruising (19p), the other for water sports (17p). that is what I did with many of my boats.

 

[Adam76]

Re: Which is better

Thanks, so then the 17p would get me on plane faster correct?

 

[Scott Danforth]

Re: Which is better

yes, watch the RPM's so you dont over-rev

 

[Texasmark]

Re: Which is better

You may be pleasantly surprised with the SS prop. Most SS props come cupped which could add the equivalent of 2" of pitch especially with the thinner blades that most SS props have because the SS is stronger and a thicker blade is not necessary and adds to the already significant cost of SS. If the SS is ported (1 hole under each blade on the barrel of the prop near the front of the blade, then the hole shot will be even batter. The 17p regardless will give you a better hole than the 19 even if they were identical props otherwise. So the SS may up your rpm's to a better position on the "desired rpm" scale, and you may keep your 36 mph and have your hole shot too......whadda deal.

Mark