So what should I think of these #?

Boxerboy2

Lieutenant Commander
Joined
Sep 1, 2018
Posts
213
Likes
146
Age
63
Took out the Sorceress yesterday and here are my numbers, what should I think about these? The engine will spin up to the 3000RPM max power so here I am at 80% of that - 2400RPM, throttle position is at 74% (which I think is in line with the 80% of RPM #'s) and load is at 58%.

Good, Bad, or Ugly?

Thanks Engine gauge.jpg
 

Powderpro

Admiral
Joined
Dec 3, 2011
Posts
4,097
Likes
4,129
Location
The Ocean
Website
www.oneilboats.com
Boat Make
O'Neil
So you have a 3000 rpm Cummins? What’s the load % at wot? What’s your fuel burn throughout the rpm range versus the factory numbers? Being able to hit your max rpm is good, but we can give you better feedback if we have more details.
 

ARC

Captain
Joined
Sep 30, 2017
Posts
775
Likes
731
Age
66
Location
great South Bay
Boat Make
31’ eastern Casco Bay
Not much info .
answer the following

engine
hp
boat weight
gears
prop
fuel burn at all rpm
 

Boxerboy2

Lieutenant Commander
Joined
Sep 1, 2018
Posts
213
Likes
146
Age
63
Ill have to get back with the fuel burn numbers but I'm pretty sure there are not any at WOT - 3000RPM - I am at 100% throttle and 98% load
So you have a 3000 rpm Cummins? What’s the load % at wot? What’s your fuel burn throughout the rpm range versus the factory numbers? Being able to hit your max rpm is good, but we can give you better feedback if we have more details.
Im on it!
 

Powderpro

Admiral
Joined
Dec 3, 2011
Posts
4,097
Likes
4,129
Location
The Ocean
Website
www.oneilboats.com
Boat Make
O'Neil
Is your boat currently light on fuel, water, and provisions? Adding weight to the boat may push your load numbers to 100% and could cause you to not achieve 3k rpms. If the boat is already loaded to the weight it will be used daily, then 98% load at WOT is perfect. I would use the boat for a while and see if you can consistently hit 3k rpms, if you can, then you have the correct prop.
 

Ol Gilnetter

Commander
Lite User
Joined
Apr 26, 2013
Posts
403
Likes
212

Boxerboy2

Lieutenant Commander
Joined
Sep 1, 2018
Posts
213
Likes
146
Age
63
Is your boat currently light on fuel, water, and provisions? Adding weight to the boat may push your load numbers to 100% and could cause you to not achieve 3k rpms. If the boat is already loaded to the weight it will be used daily, then 98% load at WOT is perfect. I would use the boat for a while and see if you can consistently hit 3k rpms, if you can, then you have the correct prop.
I am fully loaded with the exception of about 100 gallons of fuel, everything else is on the boat and water tank is full, so I would say its where it "normally" would be run. It gets to 3,000 to 3,050 RPM fairly easily so I think I'm good on that metric, I was just surprised to see at 80% throttle/RPM that the load was as low as it shows. Ill get the Fuel consumption and GPS speeds in the next day or two and post for everyone's comments and evaluation.

Thanks everyone, I appreciate your insight and the sharing of your knowledge.
 
Last edited:

Ol Gilnetter

Commander
Lite User
Joined
Apr 26, 2013
Posts
403
Likes
212

Boxerboy2

Lieutenant Commander
Joined
Sep 1, 2018
Posts
213
Likes
146
Age
63
Just to clarify my GPS comment- you can connect your GPS signal to the Cummins Smartcraft system and get miles per gallon displayed on the Smartcraft readout. Lots of people have issues with the Smartcraft components, but when they are working they do tend spit out useful info.
That is exactly what I thought you were saying....
 

Boxerboy2

Lieutenant Commander
Joined
Sep 1, 2018
Posts
213
Likes
146
Age
63
OK - so here are real life number vs Cummins Prop Spec fuel consumption. I dont know what these mean other than it appears that my low speed fuel consumption is better than what the spec is - my wife says I'm certainly wrong.... - probably within the error rate of the fuel flow sensor.

For the Cummins Spec numbers I am taking the GPH straight off the Cummins chart and for % Power I am taking their Throttle Power and dividing it by max HP, but it does not seem right.

Thoughts?

1621298045005.png
 

chortle

Captain
Joined
Mar 7, 2012
Posts
942
Likes
546
Location
Annapolis, MD
Boat Make
Herreshoff Coquina, 1972 Jarvis Newman 36, PT11
Those numbers look good. I would start planning the fun times you have been imaging.
 

Seanair

Lieutenant
Joined
May 17, 2013
Posts
69
Likes
71
Location
Rhode Island
Those numbers look great to me. I have a QSB 5.9 but its 305 HP, rated at 2,600 rpm's. Load is impacted by lots of factors: hull shape, weight placement, the angle of the boat from bow to stern. Ass stuck down low can drive up the load %, or if she gets up on a plane a bit thats going to lessen it.

Here are my numbers but I don't have the load data - I'll try and add that in - I'm heading out today for a bit, I'll see what I can jot down. (speed is knots)

Screen Shot 2021-05-23 at 9.57.20 AM.png
 

Seanair

Lieutenant
Joined
May 17, 2013
Posts
69
Likes
71
Location
Rhode Island
I jotted down some numbers yesterday - but lesson learned; should have done it on the way out, and not on the way in! Boy did the wind pick up. We were bouncing around a bit and I ran through the rpm range kind of quick, so these numbers are not spot on, and it was just to much to get up to wide open throttle at 2,600 but here are some ball park figures for my QSB.

Screen Shot 2021-05-24 at 8.44.01 AM.png
 
Top Bottom