3 blade to 4 blade prop 195deckboat-gctid811918

[Mrwalleyeman]

Memorial weekend was out at Lake Roosevelt in eastern Washington, I scraped some rocks with my prop at idle and scraped some of the tip of all 3 blades on the prop. I was docked at the boat launch at Fort Spokane facing away and on the opposite side from the launch went up to get my truck and when I backed in I pulled away from the dock to go around and hit the rocks at idle speed. So now to my question is going from a 3 blade 14.5in 19 pitch prop to a 4 blade 14.5in 18 pitch prop going to hurt anything for the rest of the breakin period.

My local prop shop has recommended the 4 blade prop for better hole shot and it being a 18 pitch prop that my overall performance will be better, also said that I would be able to plane out faster and top end performance would be better. They also said that I would be able to stay on plane at lower speeds.

Just wanted to get some opinions from everyone here, thanks.

[Chief_Alen]

If you were able to achieve recommended wot rpm with the 3 blade, and not go over, the 4 blade you mentioned will be ok.

[Aircraftbuilder]

I recently went from a 3 blader to a 4 blade. My first try was going from a 14" x 19 p 3 blade to a 14.5" x 17 p Amita 4. Lost speed and over reved. Next try was with a Mercury Spitfire 14" x 19 p. The literature on this prop states that if you are within acceptable rpm limits n your 3 blade, go with the same diameter and pitch with the Spitfire. I have been very pleased with this setup. Faster out of the hole, faster on plane and just plain faster! This is for a 2052 with a 3.0 liter.

Good luck.

[Driver86]

"Mrwalleyeman" post=811918 wrote:
Memorial weekend was out at Lake Roosevelt in eastern Washington, I scraped some rocks with my prop at idle and scraped some of the tip of all 3 blades on the prop. I was docked at the boat launch at Fort Spokane facing away and on the opposite side from the launch went up to get my truck and when I backed in I pulled away from the dock to go around and hit the rocks at idle speed. So now to my question is going from a 3 blade 14.5in 19 pitch prop to a 4 blade 14.5in 18 pitch prop going to hurt anything for the rest of the breakin period.

My local prop shop has recommended the 4 blade prop for better hole shot and it being a 18 pitch prop that my overall performance will be better, also said that I would be able to plane out faster and top end performance would be better. They also said that I would be able to stay on plane at lower speeds.

Just wanted to get some opinions from everyone here, thanks.

I have the same boat and was wondering what prop you ended up going with and how do you like it?

[Mrwalleyeman]

Driver86 I did get the 4 blade 18 pitch prop but only took it out for a few hours with it. So not sure how well it performs as of yet.

I did get the boat up to 42 mph, that was with the speedo on the boat, but didn't look at my tach to see what my RPMS were.

Anyway heading out this weekend and will get a good chance to really test it, and will report back with my findings.

[Mrwalleyeman]

Went out yesterday and here is what I have with the 4 blade 18 pitch 14.5 inch prop,

Max speed was 45-46mph @ 4600- 4700 rpms the speed was from the boats speedo.

I could not squeeze anymore out of her. The boat seemed to plane out a little faster.

So I'm not sure if the speed I was getting at those RPMS are about what they should be,

Or if I should be able to have squeeze a little more out of her.

[Driver86]

"Mrwalleyeman" post=814839 wrote:
Went out yesterday and here is what I have with the 4 blade 18 pitch 14.5 inch prop,

Max speed was 45-46mph @ 4600- 4700 rpms the speed was from the boats speedo.

I could not squeeze anymore out of her. The boat seemed to plane out a little faster.

So I'm not sure if the speed I was getting at those RPMS are about what they should be,

Or if I should be able to have squeeze a little more out of her.

I really appreciate the input. Based on your experience I am almost thinking I should go with a 17 pitch instead of a 18 pitch as I really want to increase my getting on plane performance. We rarely go over 35-40 mph. Im thinking our top speed would still be 40-42 mph. Anyone else with prop experience that could shine some light on whether the 17 pitch would give me a little more low end grunt?

[Driver86]

"Mrwalleyeman" post=814839 wrote:
Went out yesterday and here is what I have with the 4 blade 18 pitch 14.5 inch prop,

Max speed was 45-46mph @ 4600- 4700 rpms the speed was from the boats speedo.

I could not squeeze anymore out of her. The boat seemed to plane out a little faster.

So I'm not sure if the speed I was getting at those RPMS are about what they should be,

Or if I should be able to have squeeze a little more out of her.

Well I guess I shouldn't have assumed my prop was the same as yours even though we have the same boat except for mine is a 2015 and yours is a 2016. The stock prop on mine is a 14.25x21P. I wonder if they made the jump to the 14.5x19P for the 2016 model year to get it up out of the water a little better. Am I correct in thinking the 14.5x19P came on the boat from the dealer?

[Mrwalleyeman]

I apologize for taking so long to get back to this. Yes the dealer put the 14.5in 19 pitch 3 blade on there.

[Mrwalleyeman]

I apologize for taking so long to get back to this. Yes the dealer put the 14.5 X19 3 blade on there.

[Driver86]

"Mrwalleyeman" post=817609 wrote:
I apologize for taking so long to get back to this. Yes the dealer put the 14.5in 19 pitch 3 blade on there.

Quite interesting, I know all the boattest articles list the boat with the prop that I had. We moved to the 4 blade 14.25 19 pitch and so far its been great. Definitely gets out of the hole much better when the boat is loaded and we didn't loose much of anything on top speed.

[Chief_Alen]

Speed is secondary, you must not excide recommended wot rpm for your engine.

Use gps for the speed, do not maintain wot for long periods of time, 2/3 wot is cruising the rest for emergencies.

I reached wot 2 times a year, at the beginning and end of season, and only for 5 minutes.

[Mrwalleyeman]

So after having the 3 blade prop repaired and using the 4 blade 14.5" 18 pitch prop for most of the summer I decided to put the 3blade 14.5" 19 pitch back on the boat. After doing so I have been out a couple times and noticed that the hole shot seems to be better with the 3 blade than the 4 blade (about 1-2 seconds faster). I know I said before that the 4 blade seemed to plane out a little faster but now I don't think that's the case.

Also my WOT top speed and rpms are fairly close to what I was getting with the 4 blade, I was getting 45 to 46 mph at about 4600-4800 rpms with the 3 blade, Where before with the 4 blade I was getting 45-47 mph at 4600 -4700 rpms.

I have not changed anything in the weight distribution of the boat. My wife and kids have have their spots on the boat which has been the pretty much the same since the first time out in early April. Always top off the fuel before heading out. So nothing has really changed.

Just thought I would report back after some more time with using both props.