Reb13
New Member
Any experience out there with replacement /spares? 32x28 nibral are what's on there now. Runs great but wouldn't mind a few more mph!
Thanks,
Reb
Thanks,
Reb
480DB props
- Thread starter Reb13
- Start date
- Oct 6, 2006
- 12,153
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
Welcome to CSR..............but it does not quite work that way.
Your engines need to turn up to the manufacturer's maximum rated rpms at wide open throttle. If they do, you are propped correctly. More pitch and you overload the engines; less pitch and you over rev the engines. In the world of diesel engines, neither is a condition conducive to long engine life.
I can tell you that your props are going to be close to right if they are original equipment and have not been altred. If you are not able to turn up WOT rpms (likely by 50 -100 rpms with a full load), or if you turn more than WOT rpms, then you should have a propshop repitch and balance your wheels to yield the max rated engine speed.
Your engines need to turn up to the manufacturer's maximum rated rpms at wide open throttle. If they do, you are propped correctly. More pitch and you overload the engines; less pitch and you over rev the engines. In the world of diesel engines, neither is a condition conducive to long engine life.
I can tell you that your props are going to be close to right if they are original equipment and have not been altred. If you are not able to turn up WOT rpms (likely by 50 -100 rpms with a full load), or if you turn more than WOT rpms, then you should have a propshop repitch and balance your wheels to yield the max rated engine speed.
sbw1
Well-Known Member
- Oct 10, 2006
- 8,185
- Boat Info
- This is listed in my signature
- Engines
- This is listed in my signature
Reb13 said:
If you are currently achieving the specified WOT, have them Prop Scanned. You will likely pick up some speed while keeping your loading at the proper level. I was initially skeptical of the PS marketing claims but did pick up efficiency with new nibral props that seemed fine prior to scanning. My top speed went from 39 to 41 MPH.
Sea Gull
Well-Known Member
As suggested, the engines need to spin up to (or slighly above) their rated WOT rpm. But this should be under normal (perhaps maximum) load. My limited experience with the two new Sea Rays that I have bought indicates that Sea Ray always overprops their boats slightly. This means that the boat will get to the WOT rating during sea trial, but not once you have added 2 weeks worth of crusing gear, a dinghy and marine growth on the bottom.
Regardless of the above, you need to start by getting the props scanned and trued up to their original specs, and the bottom as clean as possible. Then, load up the boat and see what WOT you get. Check with the engine MFG as to what they recommend for WOT. (for example, my MANs are rated at 2300 rpm, but they recommend being able to get 2350). Once you know the above, you can work with the prop shop to tweak the props to the ideal pitch.
The bad news is that overpropping is also going to give you more speed. The good news is that correctly propping the boat will give you the most efficient cruise in terms of fuel used.
By the way, welcome to the board. Where are you located?
Regardless of the above, you need to start by getting the props scanned and trued up to their original specs, and the bottom as clean as possible. Then, load up the boat and see what WOT you get. Check with the engine MFG as to what they recommend for WOT. (for example, my MANs are rated at 2300 rpm, but they recommend being able to get 2350). Once you know the above, you can work with the prop shop to tweak the props to the ideal pitch.
The bad news is that overpropping is also going to give you more speed. The good news is that correctly propping the boat will give you the most efficient cruise in terms of fuel used.
By the way, welcome to the board. Where are you located?
Reb13
New Member
Thanks for the info. Does anyone know a good source for new props other than going thru Sea Ray.
Willa Gin home port LGYC, TNR 358.
Thanks,
Reb
Willa Gin home port LGYC, TNR 358.
Thanks,
Reb
sbw1
Well-Known Member
- Oct 10, 2006
- 8,185
- Boat Info
- This is listed in my signature
- Engines
- This is listed in my signature
People have different views on props. Michigan Wheel enjoys a good reputation and has contracts with high end builders. Others will have other views. Another point on prop loading---as your boat picks up weight, slime other marine growth, your wot rpms will go down. It's important to lower your cruise throttle settings until you get the bottom cleaned and back to wot spec so you avoid overloading the engines.