Emie Boyer
New Member
- Aug 23, 2017
- 25
- Boat Info
- 39 express
- Engines
- 454 Merc
what prop to run to get max performance
39 EC with 454
- Thread starter Emie Boyer
- Start date
hottoddie
Well-Known Member
- Jan 11, 2012
- 2,230
- Boat Info
- 1986 Sea Ray 390 EC
Garmin 4212 Chartplotter
Garmin 24 HD Radar
Garmin 546s Plotter
- Engines
- 454 Crusaders
Factory props are 19X18 with a medium cup should get you 4200-4400rpm at WOT. Trying to put more prop for more speed will lower your WOT rpm and overload the engines. No magic bullets to be had.
RollerCoastr
Well-Known Member
- Nov 15, 2007
- 3,884
- Boat Info
- 1997 400DA
340HP 7.4 Mercruiser Bluewaters
Garmin 741, 742, 8212, 24HD, Intellian I2
- Engines
- 1999 280BR
Twin 250HP Merc 350 Alpha Ones
Very true, but there is the whole 3-blade vs. 4-blade discussion...
Emie Boyer
New Member
- Aug 23, 2017
- 25
- Boat Info
- 39 express
- Engines
- 454 Merc
Thanks Guys
hottoddie
Well-Known Member
- Jan 11, 2012
- 2,230
- Boat Info
- 1986 Sea Ray 390 EC
Garmin 4212 Chartplotter
Garmin 24 HD Radar
Garmin 546s Plotter
- Engines
- 454 Crusaders
While each boat is different going to 4 blades "usually" will get some improved docking capabilities and lose you a little in top speed. The 390EC will handle at the well enough with 3 blades if you use some extra throttle due to the very large prop tunnels. I did the 4 blade experiment on my last boat (32ft inboard express) and lost 3 knots top end and no improvement in dock handling. Larger diesel boats benefit from 4-5 blade props more than smaller gas boats IMHO.
