Offshoreonly.com - Prop Selection Help Needed

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Prop Selection Help Needed

I have a 21 ft 1986 Scarab 1 that I need some help with the prop selection on. I tried doing a little searching and found a little bit but I just wanted to make sure before I pulled the trigger on a new prop for the boat. I know that top speed and hole shots are arch enemies when choosing a prop, so I will just have to compromise. I will be skiing off my boat, so the 3 blade will be the better choice for that, but on other days speed will be what I'm going for.

As of right now, I am under the impression that a 4 blade, 22-24 pitch prop is the way to go for hole shots, and a 3 blade with the same pitch for speed. My boat is a 21ft Scarab, with a 302 sb, and RPMS at WOT are right around 3500, which I know is way too low. If I trim up a bit they go up a bit, but not enough. From what I see I should be running about 5000-5500 RPM at WOT. This is my first boat of this type, and have had smaller ski boats in the past, and I am currently not sure of what my current pitch is on the 3 blade that is on there now is. Any suggestions?

my 22 scarab with 454 stock came with a 25 3 blade. 23 sounds about right for you

Quote:

Originally Posted by kosmo 04 (Post 3139400)

As of right now, I am under the impression that a 4 blade, 22-24 pitch prop is the way to go for hole shots, and a 3 blade with the same pitch for speed. My boat is a 21ft Scarab, with a 302 sb, and RPMS at WOT are right around 3500, which I know is way too low. If I trim up a bit they go up a bit, but not enough. From what I see I should be running about 5000-5500 RPM at WOT. This is my first boat of this type, and have had smaller ski boats in the past, and I am currently not sure of what my current pitch is on the 3 blade that is on there now is. Any suggestions?

As a rule of thumb you go one step higher in pitch with a 3 blade. Example if you had a 21P 4 blade you would go to a 23P 3 blade. Really need to know what you have on it now. It should be stamped on it somewhere. However it sounds like you may have some other problem if it will only turn 3500 rpms at wot. It's hard to make any recommendations with this info. In my opinion I would say a boat like that with a small block would use a 19-21 3blade or 17-19 4blade.

my 91 with 454 came with a 23P. With your SB i would look at a 21P

I now switch between a Hydro 24P 4 blade a 23P mirage and a 25p Mirage plus depending on what the water is like and what I am doing:coolcowboy:

You also need to pay attention to if the prop is a mirage or a mirage plus.

Take a look at the rev 4 props I have heard that they are a goo all around prop for speed and skiing.

A 4 blade is better for hole shot and pulling skiers and a 3 blade is better for top end.

I had a Scarab 21ss with a stock 350 and settled on a Mirage 3 blade 21p