MHARSANY
New Member
Does anyone have any good options that have worked for them for propellers that have increased speed at same RPM and lowered fuel consumption. 1991 400EC.
Propeller options on 400EC
- Thread starter MHARSANY
- Start date
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
Mike, do you have reason to suspect that you're under-propped?
MHARSANY
New Member
No, It is just in certain casual conversation circles, I have heard of people saying they are using this prop or that prop and it has given them more speed and better fuel consumption. Always in a place where I can write it down and now while the boat is close to going back in, I am trying to address...
sprink56
New Member
- Oct 28, 2008
- 1,288
- Boat Info
- 1979 255 Liberator
- Engines
- twin Mercruiser 450 HP I/O on Bravo I Drives
I never tried it...but I believe Frank Webster mentioned that the buyer of his 390EC switched to 4 blade props and gained an advantage. I think the idea is to drop 1" in pitch with a 4 blade and you get a bit more dig out of the hole and can maintain a plane at lower speeds. The sacrifice is a MPH or 2 at the top....but in reality, top end is not what we're after in these boats.
Share what ever you learn or experience.
John F
Share what ever you learn or experience.
John F
- Oct 6, 2006
- 12,155
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
Sea Ray does a very good job matching props to the boats. You will gain very little with any change if your engines are already able to turn up to rated rpms. If they either over speed or can't reach rated rpms then a change may help you, but we are most likely talking about a very minute change.........unless your boat had has someone screwing with the props previously.
As John mentioned, the new owner of my old 390EC eventually repowered and had to change transmissions for the engines he chose. He changed from 3 blade to 4 blade props when he did. On the 39 it improved his low speed handling some and he got about .5 mph more at wot. Cruise didn't change and fuel burn remained the same. The 4 blade props with less pitch give you the same effective pitch with less slippage at low speeds and decreasing advantages as rpms increase. The 400EC is a better slow speed handling boat due to shallower pockets and more draft and is also faster due to less beam and wetted hull than the 390EC, so I seriously doubt your gains would be worth a change, considering the $2500 or so a new pair of props will cost.
As John mentioned, the new owner of my old 390EC eventually repowered and had to change transmissions for the engines he chose. He changed from 3 blade to 4 blade props when he did. On the 39 it improved his low speed handling some and he got about .5 mph more at wot. Cruise didn't change and fuel burn remained the same. The 4 blade props with less pitch give you the same effective pitch with less slippage at low speeds and decreasing advantages as rpms increase. The 400EC is a better slow speed handling boat due to shallower pockets and more draft and is also faster due to less beam and wetted hull than the 390EC, so I seriously doubt your gains would be worth a change, considering the $2500 or so a new pair of props will cost.
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