Need/Want a spare prop - can't make out what I have now

[Mikejr]

Boat = Bayliner 175 (2005), with the standard mercruiser 3.0L power package.

I want to purchase a new/spare prop and noticed one post about getting one 2 degrees lower for those watersports days.

Question 1 - does the expertise here agree with that idea?
Question 2 - I can't make out what the numbers mean and my manuals say refer to prop. Can you please look at the attached pictures and let me know what they mean and what I have (I think 21 degrees, but not sure).

2 close ups of the prop data and one zoomed out view:

1 -

2 -

zoomed out view -

Also - if I order from the Iboats site, do i need to order the inner part (name?) as well?

Thank you,
Mike

 

[T_Herrod]

Re: Need/Want a spare prop - can't make out what I have now

Do you have a prop shop anywhere near you? If so remove the prop and have them measure it and fiure the pitch. If not there are some pretty good web sites that show you how to measure and figure the pitch of a prop. I went through the same thing when i wanted a spare prop.

 

[steelespike]

Re: Need/Want a spare prop - can't make out what I have now

The key number is the 21 It refers to 21" pitch. Pitch is the theoretical distance forward the prop moves in one revolution.
Actually is less do to operating in a liquid. identified as slip measured in percent.
The other numbers refer to material ,aluminum,stainless,and the application etc. The 48 prefix indicates a Merc number.
21" is a pretty typical size for a 3.0 in a 17-19 ft boat.And may struggle with water sports.
The inner portion is the "hub" there are pressed in hubs and removable hubs.
If you look up 21" prop for 3.0 Mercruiser in the iboats store you will find many choices from a number of companies.
We'll help you through the confusion.
If you read the stickys at the top of the prop forum and get us as much info as possible we can help you determine
if a change is in order.

 

[JaseBosto]

Re: Need/Want a spare prop - can't make out what I have now

I had a 21" on my 18ft stingray. It was a dog out of the hole but had good top end. 50mph on GPS but that hull was relatively flat compared to a bayliner. 19" was what I usually ran, did ok wakeboarding so it had decent hole shot. 17" was good for pulling.

 

[Mikejr]

Re: Need/Want a spare prop - can't make out what I have now

I've read the posts and am still a bit confused. Based on what you've said (and others, thanks all) I think I have the 21. If you don't think it's a bad idea to have a 19" for my engine and alpha 1 leg, that seems like a good idea for a spare. I have read though, that using a lower (or higher pitch) can have some problems, but I must admit I have not quite been able to determine if going down 2" is problematic or not.

Then there is the various types and they range from about $111 to $153 and I can't tell the difference...sometimes you get what you pay for and if spending a few extra bucks is worth it, I'm ok with it...but sometimes it's all same same.

Is there an advantage over pressed in versus removable hubs? What are the pro/cons I should consider?

Thank you so much!
Mike

 

[steelespike]

Re: Need/Want a spare prop - can't make out what I have now

We can't make an informed suggestion for a replacement prop without your present wot rpm and gps speed with a light load.
We need this for the numbers and to evaluate your setup.Without the numbers we can't tell your final results with a 2" pitch reduction.No doubt the 2" drop in pitch will help hole shot.
The Solas Props have an excellent reputation for good predictable results.
From the postings Ive seen It appears the Rubex costs slightly less than the Amita because the installation accessories are included.
The removable hub makes it slightly less expensive to try different props also down the line if you change motors/boats with similar
prop needs you could just get a hub so to use an existing prop on a different brand but similar size prop need.
Also if you came upon a Rubex prop from a different motor but a good size for yours your hub would work.
Wow! am I making sense?

 

[JaseBosto]

Re: Need/Want a spare prop - can't make out what I have now

We can't make an informed suggestion for a replacement prop without your present wot rpm and gps speed with a light load.
We need this for the numbers and to evaluate your setup.Without the numbers we can't tell your final results with a 2" pitch reduction.No doubt the 2" drop in pitch will help hole shot.
The Solas Props have an excellent reputation for good predictable results.
From the postings Ive seen It appears the Rubex costs slightly less than the Amita because the installation accessories are included.
The removable hub makes it slightly less expensive to try different props also down the line if you change motors/boats with similar
prop needs you could just get a hub so to use an existing prop on a different brand but similar size prop need.
Also if you came upon a Rubex prop from a different motor but a good size for yours your hub would work.
Wow! am I making sense?

IF I use my previous boat as a comparison, 18ft stingray bowrider, 3.0 mer alpha one. I had a 3 bladed stainless 19" pitch prop on it. Good all around prop. 17" was best. The 19" was good because it had acceptable hole shot but got me over 45mph. If I remember correctly, 21" was borderline too much for that boat. RPM's was at the minimal acceptable range. 17" was great because it would get out of the hole good with any amount of weight onboard.
So, my unofficial recommendation is 17" pitch to 19" pitch.

 

[agallant80]

Re: Need/Want a spare prop - can't make out what I have now

mercruiser has a prop selecter on their website you can use.

Prop Selector | Mercury Marine