Passage 450 Motoring Range?

[Bowedtoothdoc]

Can any others comment as to the validity of my calculations or their personal experiences on their boats?

Engine is a Yanmar 4JH2-HTE Fuel Tank 100 Gallons
Fuel usage at 2500 rpm is approximately 1.5 Gallons per hour and boat speed is 7 Knots or 8 mph. Estimating leaving 10% or 10 gallons not to run the tank dry leaves 90 gallons for the range calculation. So 90 divided by 1.5 is 60 hours of motoring with a range of 480 statute miles or approximately 430 nautical miles.

Thanks,

 

[All U Get]

I wouldn't think there was much tide or currents on that lake, so your numbers seem reasonable. Punching into a chop could slow you down.

All U Get

 

[KD3PC]

same engine in a Passage 42, I planned on 1 gal per hour, real flow was closer to .6 gal hour, but the difference gave me a margin that was good.

Your numbers may be a tad conservative, but would also give you a margin of safety.

Good Sailing

 

[chasmoyer]

Actual tank capacity is 94 gal. Run engine below 2400 rpm to keep turbo off and you will get 6.5 speed and burn .8 gph.....extending your range and comfort.

 

[Bowedtoothdoc]

Actual tank capacity is 94 gal. Run engine below 2400 rpm to keep turbo off and you will get 6.5 speed and burn .8 gph.....extending your range and comfort.

Thanks for the replies...Chas, How did you get this info regarding the turbo?
I guess you have measured your fuel efficiency? I have a Maxprop on my boat..
What sort of prop are you using?

 

[chasmoyer]

Thanks for the replies...Chas, How did you get this info regarding the turbo?
I guess you have measured your fuel efficiency? I have a Maxprop on my boat..
What sort of prop are you using?

rpm info from engine mechanic... I am using a fixed 3-bladded prop...I think 18.5 inches...had it tuned at last pull out and bottom painting.

 

[kingsailor]

GPH

Boy what am I doing wrong? I calculated 2.5 GPH after over 1000 hrs of motoring. Same boat same engine, various conditions. Help!

 

[Rick486]

Boy what am I doing wrong? I calculated 2.5 GPH after over 1000 hrs of motoring. Same boat same engine, various conditions. Help!

Do you have a generator? If so have you accounted for it's diesel burn? On my boat they draw from the same tank.

 

[All U Get]

Heading south there would be the Gulf Stream, heading north you're going uphill.

All U Get

 

[Bowedtoothdoc]

The generator feeds off of the same tank, but I am not taking that into account for calculation purposes. From what I have read an 8Kw genset will burn .5 to .75 gallons per hour depending on the load. I would plan on estimating 1 gallon per hour to be safe.
Someone correct me If I am wrong.

 

[kingsailor]

Re: GPH

Good point. I ran the genny approx 2/3 hrs a day. I also like to take full advantage of the 76 HP and on long passages where we are forced to motor and run it at 2700 RPM and try to maintain 7/8 knots. No reason to linger in the gulf stream. Also my mechanic says that it is healthier for the diesel to run at a higher RPM. Of course he is not paying the fuel bill!

 

[Bowedtoothdoc]

Hello Everyone,
I just came across this information...

http://seamoss.dhs.org/yanmareng.html

seems to conflict with info from Chas indicating that @ 2400 rpm fuel consumption is 1.28 Gph rather than the .8 for our engine that Chas has provided. Can anyone provide any more info on this?

 

[kingsailor]

Fuel range

Correct me if I'm wrong, if I am burning 2gal/hr at 2700rpm and have 100 gal then I can motor for 50hrs at approx. 7kts = 680 KM cruising distance.

 

[Don Lucas]

Correct me if I'm wrong, if I am burning 2gal/hr at 2700rpm and have 100 gal then I can motor for 50hrs at approx. 7kts = 680 KM cruising distance.

50 hrs at 7kts = 350 km, you must be using new math

a lot of guys must really be in a big hurry, if I run my 410 at 5.5 kts I burn 0.6 gph and can motor 450km on my 50 gal tank

 

[Bowedtoothdoc]

50 hrs at 7kts = 350 km, you must be using new math

a lot of guys must really be in a big hurry, if I run my 410 at 5.5 kts I burn 0.6 gph and can motor 450km on my 50 gal tank

Don,
Not sure what engine you have, but I have a 4JH2-HTE turbo deisel. Seems like the sweet spot for the engine according to the chart is somewhere between 2200 and 2700 RPM and fuel consumption according to the chart I noted above should be between 1 and 2 GPH. I am just trying to verify if that is correct and what the "sweet spot" for motoring efficiency should be.
Also how having a turbo impacts engine performance and motoring efficiency.

 

[Don Lucas]

Seems like the sweet spot for the engine according to the chart is somewhere between 2200 and 2700 RPM and fuel consumption according to the chart I noted above should be between 1 and 2 GPH. I am just trying to verify if that is correct and what the "sweet spot" for motoring efficiency should be.
.

I bet there is a big fuel efficency difference between 2200 rpm and 2700 rpm!

On my boat is is pretty to tell the sweet spot by the sound.

 

[Bowedtoothdoc]

I got a chance yesterday to do some recording of boat speed at various rpm, not sure how accurate that Yanmar rpm gauge is on my engine panel, but here is what I got:

6 Knots @ 2000 Rpm
6.2 Knots@ 2100 Rpm
6.5 Knots @ 2200 Rpm
6.7. Knots @ 2300 Rpm
7 Knots @ 2400 Rpm
7.2 Knots @ 2500 Rpm
7.3 Knots @ 2600 Rpm
7.5 Knots @ 2700 Rpm
7.6 Knots @ 2800 Rpm
7.7 Knots @ 2900 Rpm
7.8 Knots @ 3000 Rpm
8 Knots @ 3500 Rpm