94 290 Sundancer questions

[Btcowboy]

So I bought a 94 290 and have a couple questions. It has twin 4.3 ltr mercruisers. I believe they are bravo 1 legs. I installed the stingray hydrofoils on the legs.

Originally I had 3 blade19 pitch SS props on her. When I pulled it out of the water it was suggested to swap to my aluminium props. However they are 4 blade 17 pitch. I went from 33 mph at 3300 rpm to 20 mph at 3300 rpm. To me this makes my fuel mileage way worse

1. What's the best prop to keep my cruising RPM down and increase my fuel mileage?

2. What is good mileage for this boat.

 

[GrandMaster]

I think you probably have Alpha I Gen 2 drives unless they have been changed somewhere along the line.

If you have 1.84:1 drive ratio Alphas I believe the props the boat came with (and what I have) are 3 blade 13.75X21 QSS with a wide open throttle of 4,800.

Fuel mileage varies alot depending on speed, RPM, and sea conditions, but at wide open throttle (+/-44mph) on calm seas I can get around 1 MPG. Minimum planing power for me is about 3,100RPM with better fuel economy. I dont track the fuel mileage very closely though because there are just some things I'm better off not knowing.

With the proper 4 blade prop your fuel mileage and minimum planing power should be better than mine but top speed would suffer

Sal A here has the same boat with hyrofoils & recently put on 4 blades and seemed happy. You might want to send him a message & ask his thoughts: http://clubsearay.com/member.php/27996-Sal-A

 

[Btcowboy]

Thanks Grandmaster, I was researching yesterday and came up with the same prop. The boat came with a 19 pitch and spare 17 pitch. Not sure why the previous owner switched, maybe didn't know better. I am thinking of putting my 19 pitch back on and then somewhere down the line buy the 21 pitch.