202 Crownline prop questions

btucker75

Recruit
Joined
Nov 27, 2012
Messages
2
1. Trying to increase holeshot/pulling power
2. not sure about prop manufacturer, but it is currently a 14.5 x 19 3 blade aluminum prop
3. WOT with me and a passenger = a litle under 5000, top speed about 45ish (speedo).
4. 5.7 Mercruiser (2bbl carb), alpha 1, 1997(but replaced a few years before I purchased. Same model used), 210HP
5. Crownline 202br, 20'2", weight-unsure

History - Originally had a 15 x 19 3 blade aluminum prop. WOT then was 4800 (me and one) at 47mph. Good all around. Sacrificed the prop to the rock gods, replaced with a 14.5 x 19 (all the lake guy had). Worried about over reving, but noticed a better holeshot. I usually have a BOATLOAD(ex. 5 adults, 4 young uns) pulling large towables, andd getting into wakeboarding (just added a tower). I am 6'2" 245 and can get up with the load only because I can hold my breath a long time. At that load, the boat will still reach 40+ when trimmed out. Normal cruising is 25-30.

Problem - Boat is trying to plane at the speeds I need to go to both tube and Wakeboard. It takes a throttle artist like myself to give a smooth ride. Takes awhile to plane. I am looking to pull stronger, and plane at a slightly lower speed. I don't mind losing several mph top end. Have researched, but have some detail issues.

Props - Want to move to a 4 blade and drop down to an 18p. If diameter is the same, shouldn't be a problem. I want stainless though. Can only find the 14 3/8".

Question - Will I risk over reving with the drop of pitch AND diameter even though I move to stainless? How much will diameter affect the numbers? Should I consider a 5 blade? If so, dimensions? Experience? Alternatives? Advice? I just want to do it right. Thank you
 

jestor68

Commander
Joined
Jun 12, 2012
Messages
2,308
Re: 202 Crownline prop questions

In order to establish some basic ground rules; The 1997 5.7L rpm range is 4200-4600 rpm. It has a 1.62 gear ratio.

The boat has a dry weight of about 3100 lbs. Lets add about 1465 lbs for the 9 people, gear, and fuel. So we have an operating weight of about 4565 lbs.

Putting your numbers through the Mercury Marine prop selector comes up with a 20" pitch in 4 blade aluminum, and a 19" pitch in a SS 4 blade prop. The diameters of these props range from 14 to 14-1/4, so that's not a factor to consider.

You will notice that the recommended props do not follow the usual "rule" of dropping an inch of pitch when going to a 4 blade. That's because you're already over the max rpm by 200 rpm. :)
 

btucker75

Recruit
Joined
Nov 27, 2012
Messages
2
Re: 202 Crownline prop questions

In order to establish some basic ground rules; The 1997 5.7L rpm range is 4200-4600 rpm. It has a 1.62 gear ratio.

The boat has a dry weight of about 3100 lbs. Lets add about 1465 lbs for the 9 people, gear, and fuel. So we have an operating weight of about 4565 lbs.

Putting your numbers through the Mercury Marine prop selector comes up with a 20" pitch in 4 blade aluminum, and a 19" pitch in a SS 4 blade prop. The diameters of these props range from 14 to 14-1/4, so that's not a factor to consider.

You will notice that the recommended props do not follow the usual "rule" of dropping an inch of pitch when going to a 4 blade. That's because you're already over the max rpm by 200 rpm. :)



So I'll still gain hole shot and pulling/planing like I want by staying same pitch, but dropping diameter? Should I consider a high 5?
 

jestor68

Commander
Joined
Jun 12, 2012
Messages
2,308
Re: 202 Crownline prop questions

A 19" High Five was on the list too. The reason it was recommended to stay with the same pitch was because your rpm was already over the limit. These props will pull the WOT rpm down a little(100-200 rpm), while still providing the desired boost in hole shot and steady running at lower speeds.

Remember prop selection rule #1; select a prop to let the motor operate within it's recommended rpm range.
 
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