Bigsfish
Guru
- Joined
- Aug 29, 2016
- Messages
- 2,997
- Location
- USA
- Vessel Name
- Gotcha
- Vessel Make
- Grand Banks. Heritage. 54
The facts:
Cummins QSB 6.7 480 hp
When new with ½ fuel, ¼ water and minimal supplies. 3350 rpm @ 23.2 knts. WOT
Now 51000 lbs ½ fuel, ½ water normal supplies . 3050 rpm 19.5 knts. WOT
Boat has Zeus pods so new props (2 / engine) is 4 props. $9100.00 to replace.
I want to get the boat to top rpm of 3350 again. The boat has always felt under powered to me. A friend has an East Bay (12 inches longer and 10000 lbs less w/o a bridge and the same maker put the same engines in his boat but they were rated at 550 hp. (140 hp more than my boat) and his performs much better.
I can get Cummins to rerate these engines to 550 hp for $10000.00 ( includes new water pumps at $1000.00 each).
To me it's a no brainer to rerate the engines ( I know it will use more fuel and that's not a factor). The boat now cruises at 2800 and 17.8 knts but I want it slightly higher at 3000 rpm and 3350 WOT.
What am I missing? What say you?
TIA
Cummins QSB 6.7 480 hp
When new with ½ fuel, ¼ water and minimal supplies. 3350 rpm @ 23.2 knts. WOT
Now 51000 lbs ½ fuel, ½ water normal supplies . 3050 rpm 19.5 knts. WOT
Boat has Zeus pods so new props (2 / engine) is 4 props. $9100.00 to replace.
I want to get the boat to top rpm of 3350 again. The boat has always felt under powered to me. A friend has an East Bay (12 inches longer and 10000 lbs less w/o a bridge and the same maker put the same engines in his boat but they were rated at 550 hp. (140 hp more than my boat) and his performs much better.
I can get Cummins to rerate these engines to 550 hp for $10000.00 ( includes new water pumps at $1000.00 each).
To me it's a no brainer to rerate the engines ( I know it will use more fuel and that's not a factor). The boat now cruises at 2800 and 17.8 knts but I want it slightly higher at 3000 rpm and 3350 WOT.
What am I missing? What say you?
TIA