Few questions on speed

[Tyler1199]

So i've recently purchased a 99 Crownline 202BR. Boat has been decently upkept but needed bellows and such and some TLC. Bellows are completed, did new spark plugs, oil and oil filter. This boat has a 5.0 mercruiser thunderbolt ignition with a alpha drive gen 2. I honestly dont know what t expect out of speed on this thing. It feels sluggish to me- it revs good and gets into its prime RPM (4400-4800) rpm but i always seem to be trying to get more and over revving it- getting into the 5k's ( one is this even ok or should you stay away from it?) the highest speed i have seen on this is around 41mph in semi calm water and with two people on board.- with 4 of us on board and pulling a tube of two people when i was around 4600 rpm i was only going 30 or so. Any help is appreciated- i dont know if im expecting too much or what! Prop is a little banged up i think its time for a refinish and a new one and keep this as a spare. Everything else is solid.

 

[harleyman1975]

First of all have a professional fix the prop you have and take note of what size it is. (I am running a similar size boat and motor and am very happy with a 14x19 4 blade. I also can run a 14x21 3 blade but it takes longer to plane and the trade off is lower rpm's at given speeds once on plane.) Now run the prop you have once fixed and note rpm's at Wide open throttle with 2-3 people on board. 4800-5000 is where you want to be... If higher then go up in pitch (i.e. if it is 17 try a 19) If lower than 4800 (like 4400) then go down in pitch (i.e. if 19 then try 17) follow? Chances are your damaged prop is your problem...fix it and all may be well. If you do buy a spare prop I personally would get a different pitch (either one size up or down) depending on what you use the boat for the most. Props TEND to go in either odd or even pitches depending on their construction and type. Aluminum props odd numbers and stainless even...

 

[Starcraft5834]

I too am a 4 blade fan... Solas makes a fine product.. less than $150.. If your prop is beat, get a new one in the correct pitch and use the beater as a backup

 

[Tyler1199]

I too am a 4 blade fan... Solas makes a fine product.. less than $150.. If your prop is beat, get a new one in the correct pitch and use the beater as a backup

Imperial how do i figure out my correct pitch? If I go up a blade should I drop my pitch to make up for the blade resistance on the motor?

 

[Starcraft5834]

sorry for delay, yes to your answer... it all depends if you were running at WOT at the recommended 4400-4800 rpm with the 3 blade... if so, drop down 1.. should put u in ballpark

 

[Bondo]

Ayuh,..... This sounds like a prop problem, let's try the Prop Forum,....

 

[H20Rat]

-3 people on board. 4800-5000 is where you want to be...

Don't know if I'd want to be pushing that v6 that high with 3 people on board... 4800 is the max rpm per the mfg, so if you want a safety margin, shoot for 4800 with low fuel and a single person.

 

[Sea Rider]

200 rpm wot span between min and max range is nothing. Aim for max 5 K at wot with 3 up, when with less, just throttle back and watch tach to not over rev. Once there can throttle throughout the whole rpm range at the throttle you like.

Happy Boating