Fuel Mileage

[cyclops2]

Re: Fuel Mileage

As a side observation. DO NOT forget to RETRIM the drive at ANY CRUISING speed BIG BIG difference in fuel consumption.

I pick 3200 rpms. Then retrim untill I get the highest boat speed & or rpms. Simple. No GPS OR FUEL METERS ARE NEEDED.

The boat is " tuned " for that speed & load of people sitting any where they like.

 

[MH Hawker]

Re: Fuel Mileage

WOT is wide open throttle and would be the max fuel consumption and speed. A hour run with a GPS trip log would give you the distance ran and refilling the tank would give you the gallons used. And that would give you a solid GPH for any boat and motor.

 

[QC]

Re: Fuel Mileage

But what does a solid WOT GPH or MPG give him for understanding cruise? Sorry, don't get it.

 

[cyclops2]

Re: Fuel Mileage

I agree.

I simply fill the tank. Cruise till I use up 1/2 the tank. Refill. Take the gallons & distance traveled on GPS or a paper chart. Done.

I am guessing on this....Most boat tanks are NOT odd shapes. So 1/2 is about 1/2.

 

[MH Hawker]

Re: Fuel Mileage

No problem, I will use a example from a old boat I owned it has a 85 hp V 4 Johnson on a 18 ft tri hull. On a one hour run GPS verified at a average speed of 21 MPH at a distance of 25 miles it used 6 gallons that works out to .24 gallons per mile so on the OP 88 mile run it would take minum of 21.12 gallons and 4.1 hours. My new boat is a 9.9 on a 20 ft pontoon it gets .33 MPG at 12 MPH gps on a 9 mile run using 3 gallons. On the same 88 mile run it would use a minum 29 gallons and take 7.3 hours. Of course their are many variables but if you figure it at max use it would give you a good idea.

 

[Philster]

Re: Fuel Mileage

ALERT:

Who leaves the dock at 75% power, drives uninterrupted until their final destination at cruising speed and then comes off plane and drifts blissfully into the waiting port/dock? That's right, boys and girls: NOBODY.

If you get 30 MPG on the highway, and you have a highway trip planned, y'aint getting 30 MPG. You might average 23-25 with the family truckster loaded up and all the other nonsense that interrupts any and all trips.

Same deal or worse for boats: Navigating wakes, slow zones and trudging on/off the throttle eat up fuel like it's nobody's business. Be honest with your calculations. Knock off 15-20% of whatever distance you've already calculated based on info provided above.

Your results are likely to be 15-20% less than whatever you deemed optimal GPH,MPG, etc.

 

[QC]

Re: Fuel Mileage

slow zones

Actually wakeless is your best fuel economy. Just sayin' . . .

 

[Philster]

Re: Fuel Mileage

Meh. In an ideal world, slow zone is just puttering, but depending on the waterways, it's often trudge work coming on/off plane, sometimes getting up to a speed just below the point where you climb your bow wave to keep the bow up because you have confused seas coming at ya from various points, or hammerheads creating cross wakes as a barge wake/roller approaches -- and you've gone like 100 yards and there is a mess ahead to deal with yet for miles. Point being that your chumming fuel instead of sipping it on a 35 MPH skim across some mild, air infused, hull-lifting perfect chop or flat glass sea.

Yeah, slow zones are sometimes peaceful putterings past marinas... but the alert is warranted because there is often trudge work to be done by one's engine(s) that takes place off plane, back to plane, off plane, just below plane... blah blah blah.

What would you being doing QA if ya weren't bustin' chops?

 

[tpenfield]

Re: Fuel Mileage

Let's just leave it that if the OP needs to go 100 miles, he should figure fuel for 125 - 150 miles. That should cover variations in conditions, speed, harbor passage, etc.

 

[QC]

Re: Fuel Mileage

What would you be(ing) doing QA(C) if ya weren't bustin' chops?

Correcting grammar and spelling.

 

[Philster]

Re: Fuel Mileage

Funny: I am replying to your post and my wife says, "Would you just get a vasectomy already". Bwahaha.

At work, our QC department is now the QA department. I am now programmed to refer to you as QA; it's out of my conscious control. I've had to correct my posts in the past because of this.

I swear... I'm drain bead. I mean bain dread.

Dang it. I write good! LOL.

 

[elkhunter338]

Re: Fuel Mileage

I would figure worst case 2mpg. It it were me and I really wanted an accurate measurement take the boat for a test run and hook up a portable 6 gallon gas can, run for 5 miles down stream, hook back up to your main tank and return home. see how much fuel you went through and calculate from. Use your gps for distance

Are you going with a buddy, got a kicker motor. What is your plan if you have motor or outdrive trouble?

 

[Tail_Gunner]

Re: Fuel Mileage

Agreed.

I have two pet peeves:

1) All you need is torque. When in fact you need torque and RPM, and the result is horsepower . . .

2) All you need is GPH. When in fact you ALWAYS need GPH and Speed, which results in MPG . . .

Hmmmmm, just noticed my pet peeves are consistent. That's a very new thing for me, consistency

Calm down your just getting old.....

 

[Tail_Gunner]

Re: Fuel Mileage

I know, I know 1/3 to 1/3 back and 1/3 reserve. What I want to know is how many miles (approx) going in a straight line at cruising speed (35-40mph) my 1999 Chris Craft 200 Bowrider is able to go. I am planning a trip and the longest distance between marinias is 88 nautical miles. I have a 40 gal tank, the engine is running properly, 19 pitch prop, and I will have 10 gallons in cans.

We have similar boats..figure 3 mpg..Sounds like fun but do yourself a favor....Take the leg off the boat and have the alignment checked....the gimbal checked...New fresh water impeller spare prop..and have a great time. Sounds like a 10-14 hour trip of constant running for what ever reason boats dont always behave like cars in long term reliability

 

[26aftcab454]

Re: Fuel Mileage

I know, I know 1/3 to 1/3 back and 1/3 reserve. What I want to know is how many miles (approx) going in a straight line at cruising speed (35-40mph) my 1999 Chris Craft 200 Bowrider is able to go. I am planning a trip and the longest distance between marinias is 88 nautical miles. I have a 40 gal tank, the engine is running properly, 19 pitch prop, and I will have 10 gallons in cans.

I think if you run a little slower 28mph-30mph ( 2600-2800rpm)you may increase your range. My boat seems to run in it's sweet spot there just under 3,000rpm but moving along at a decent clip.
Your trip sounds great--post up of how it goes-GOOD LUCK!

 

[smokeonthewater]

Re: Fuel Mileage

honestly if you want best mpg in a river you ABSOLUTELY NEED gps AND a fuel flow meter..... no amount of guessing will help you

Your best cruise speed will vary constantly with current speed.... as the river gets wider.deeper the current slows down and best cruise (water) speed goes up and as the river gets narrower/shallower the current speeds up and best cruise speed goes down.... obviously reversing directions changes things a LOT.... generally you need to run much faster up river than down.

Look at this as a great excuse to buy some cool new toys for the boat.

 

[cyclops2]

Re: Fuel Mileage

2 things he & we do not know.

How big is the built in fuel tank. & People do like to get off of a boat after 2 or 3 hours. For many reasons. So unless the ...ONLY... fuel stop is that posted distance. You should just plan on a rest room stop or lunch or a Coffee break as a refueling stop.

I HATE 2 hours of constant droning engine noise.
I have a VERY quiet running boat. At 3200 rpms, anybody in the bow can talk EASILY, to people in the stern bench seat while eating & drinking. Stop for gas, look around & shoot the bull for a minute or 2.

 

[scrit9mm]

Re: Fuel Mileage

How many oars do you have in the boat?

What are "oars"?!?

 

[scrit9mm]

Re: Fuel Mileage

I would figure worst case 2mpg. It it were me and I really wanted an accurate measurement take the boat for a test run and hook up a portable 6 gallon gas can, run for 5 miles down stream, hook back up to your main tank and return home. see how much fuel you went through and calculate from. Use your gps for distance

Are you going with a buddy, got a kicker motor. What is your plan if you have motor or outdrive trouble?

There will be at least one other boat, and if we have any trouble it will certainly ruin the trip for everyone. No sense in planning for this... We both have a spare prop and other minor parts/tools but as soon as I prepare for anything to happen everything does!

 

[scrit9mm]

Re: Fuel Mileage

I think if you run a little slower 28mph-30mph ( 2600-2800rpm)you may increase your range. My boat seems to run in it's sweet spot there just under 3,000rpm but moving along at a decent clip.
Your trip sounds great--post up of how it goes-GOOD LUCK!

Will do, this is just the first leg of the journey. I will take pictures and keep a journal.