Planning a trip, fuel burn question.

[Lucky's]

So a few of us are planing a trip this summer to Chicago. This will be our first "long" trip with this boat so I have been trying to figure out a fuel budget. As best I can tell, my boat gets about 1mpg. Is this a correct assumption? That being the case, its 77 miles from South Haven to Chicago, so that puts me at 154 gallons for the twins. 154 gallons at an estimate of $4.25 a gallon is $655 in fuel for a 77 mile one way trip, or $1,310 for the round trip. Does this seem right?? Or is my economy estimates/fuel burn wrong. I guess that just seemed higher than I was thinking it would be for that run. Any thoughts or insight on this would be greatly appreciated!! Shaun

 

[SCORPIO]

If its 154 mile round trip then at 1mpg you'd need 154 gal *4.25=654.5, why did you double it again?

 

[Lucky's]

If its 154 mile round trip then at 1mpg you'd need 154 gal *4.25=654.5, why did you double it again?

Twin engines. That is 77 miles one way, 1mpg, x2 for twins. Right, or is my brain not working tonight??

 

[skibum]

Wait a second... You said that your boat gets 1MPG. Did you measure that with one engine running, or two?

 

[Lucky's]

Wait a second... You said that your boat gets 1MPG. Did you measure that with one engine running, or two?

I've never actually measured or checked fuel burn. I'm getting that figure from what I've read on here. Of course, both engines will be running. Ok, am I making this to confusing??:smt021 If so, please simplify it for me....

 

[Jimmy Buoy]

Before you get too hung up on 1MPG, more, or less, consider the need for fuel reserves to allow for wind/waves/storms. Many times, we've left our home port in great weather for a 4hr run up Lake Huron only to find conditions deteriorating during the trip. That can REALLY use extra fuel quickly (and cause a "pucker" factor of 10)! This is especially true if conditions become severe enough that you have to come off plane to avoid slamming.

 

[Larry]

I've never actually measured or checked fuel burn. I'm getting that figure from what I've read on here. Of course, both engines will be running. Ok, am I making this to confusing??:smt021 If so, please simplify it for me....

Yes, your doubling the fuel burn..... your boat is probably about 1 MPG (total of both motors). Round trip you will burn about 160 gallons, assuming normal cruise around 3200 RPM the entire time. As stated you do need some reserve, I would say to carry an extra 20% atleast (192 gallons in this case), I beleave your boat has 200 gallon tanks so it maybe cutting it close if you do have some weather or rough seas to deal....

 

[1956olds]

actually you have 150 gallon tank and 143 useable i think according to searay brochure.Unless youve upgraded.when you say twin 350 mercs do you meen small block chevys?Any way fillup before leaving each way you should be fine.

 

[SCORPIO]

Well, onmy 300 with twin small blocks (260hp each) at cruise of 3100 rpm, I'm burning about 12 galons per hour per engine at a boat speed of 26 mph. So in one hour I will burn 24 gal. of gas and cover 26 miles or 1.08 miles per galon, under ideal conditions. I have about 140 gal useable capacity, so my max range would be 5.8 hours or 150.8 miles. Now in the real world of currents, tides, wind etc. I would be looking for fuel after burning around 90 gal. This is where trip planning is crucial to a fun time since there may not be a fuel stop where you want one, so adjustments to fuel stops need to be planned in advance.

 

[Lucky's]

Yes, your doubling the fuel burn..... your boat is probably about 1 MPG (total of both motors). Round trip you will burn about 160 gallons, assuming normal cruise around 3200 RPM the entire time. As stated you do need some reserve, I would say to carry an extra 20% atleast (192 gallons in this case), I beleave your boat has 200 gallon tanks so it maybe cutting it close if you do have some weather or rough seas to deal....

Thanks so much for clearing that up! I was thinking that figure was per engine. I didn't realize it was total. Also, according to my owners manual I have dual 100 gallon tanks. However, I don't have a crossover so each motor draws from its respective tank.

 

[1956olds]

thats wierd ,have you located the fuel tank placard .It is usually welded to the tank and tells you actual capacity and how much available to use also.I havent seen any other weekenders our age with 100 gal tanks ,LUCKY you.

 

[Lucky's]

thats wierd ,have you located the fuel tank placard .It is usually welded to the tank and tells you actual capacity and how much available to use also.I havent seen any other weekenders our age with 100 gal tanks ,LUCKY you.

I have not done that. I was just assuming it was the same as what my manual stated. Next time I get over there I will look. I know that they are silver aluminum looking tanks if that means anything??

 

[Lucky's]

Yes, your doubling the fuel burn..... your boat is probably about 1 MPG (total of both motors). Round trip you will burn about 160 gallons, assuming normal cruise around 3200 RPM the entire time. As stated you do need some reserve, I would say to carry an extra 20% atleast (192 gallons in this case), I beleave your boat has 200 gallon tanks so it maybe cutting it close if you do have some weather or rough seas to deal....

Just to make sure I'm understanding this, when people refer to gph or mpg on this site, that number is a combined number for both engines? Sorry to be so stupid here, but I always believed that number was per engine and not overall. :huh:

 

[skibum]

Correct... The assumption when someone states fuel burn numbers on here is generally that they are referring to fuel burn "under normal operating circumstances" unless they state otherwise.

 

[chris5635]

Well, onmy 300 with twin small blocks (260hp each) at cruise of 3100 rpm, I'm burning about 12 galons per hour per engine at a boat speed of 26 mph. So in one hour I will burn 24 gal. of gas and cover 26 miles or 1.08 miles per galon, under ideal conditions. I have about 140 gal useable capacity, so my max range would be 5.8 hours or 150.8 miles. Now in the real world of currents, tides, wind etc. I would be looking for fuel after burning around 90 gal. This is where trip planning is crucial to a fun time since there may not be a fuel stop where you want one, so adjustments to fuel stops need to be planned in advance.

I would think this is about the closest estimate you can compare your burn too as far as GPH. With 200 gal capacity you shouldnt have a problem making the 77 mile trip and also have plenty of fuel to spare in case of adverse weather or other unplanned events. You wont need the 192 gals as someone else stated because you wont be making both legs of the trip at the same time. Fill up once you leave chicago again and you will be GOOD TO GO!!! Enjoy and dont forget the camera :smt038

 

[johngus]

Weekenders carry 200 Gallons of fuel.2x100 gallon tanks.Sundancers carry 150.You should be good for there and back but can you fuel up for the trip back?If so I would fuel up for the trip back,seems to hurt less to drop 300 each way then 600 at the end.maybe just my mind is crazy.