Fuel consumption...

[TBGixxer]

New boat/new boat owner. I filled the boat up after leaving the dealership (no... they did not fill it for me!). We took it out twice and had half a tank left. Before taking it out for the third time I filled her back up. We made the usual trip with maybe a little detour, but nothing major. We did have to haul it back to dock at almost wide open throttle for maybe 20 minutes. The tank is on 'E' after this one trip. Is it the time spent at open throttle and is it normal to burn through almost 44 gallons of gas in one trip? I know we didn't put but another hour on the engine.

 

[Fireman431]

Re: Fuel consumption...

Without knowing the size of the boat, the engine/outdrive configuration, the weight of the boat, and the amount of additional load (people/gear/etc), it's tough to help. I can say that unless you have a 10 gallon tank, it certainly doesn't sound normal.

 

[cribber]

Re: Fuel consumption...

Boats burn gas at different rates in their RPM range. Cruising speed in the middle of your rpm range gets you the best GPH. Check the manufacturer's website to see what you get for your setup. Or, post boat make, type, length, engine size, etc... and someone can help you out with your question. Anything from the info provided above would be a SWAG at best.

 

[TBGixxer]

Re: Fuel consumption...

I knew some key info was missing, lol. It's a 21' Seadoo. I'm not very tech savvy but it's an inboard with 2 155 hp motors. We had 7 people on the boat with a few coolers, bags, and some extra stuff. That's another thing that we didn't have the first time. We only had 4 people total on those first 2 trips with less gear.

 

[BTMCB]

Re: Fuel consumption...

Without knowing the size of the boat, the engine/outdrive configuration, the weight of the boat, and the amount of additional load (people/gear/etc), it's tough to help. I can say that unless you have a 10 gallon tank, it certainly doesn't sound normal.

+1 - need all that information Fireman suggested in order to help. Also, how long is the "usual trip"? Also, with all due respect (not meant to be sarcastic - it happens) presume that when you last filled it up, you filled the FUEL tank?

 

[bruceb58]

Re: Fuel consumption...

How many gallons did you use?
How many hours did you run?
What was your avergae speed during those hours?

Your question is akin to saying you used half of a tank of gas in your car during a day and asking what your gas mileage was.

 

[TBGixxer]

Re: Fuel consumption...

+1 - need all that information Fireman suggested in order to help. Also, how long is the "usual trip"? Also, with all due respect (not meant to be sarcastic - it happens) presume that when you last filled it up, you filled the FUEL tank?

lol, yep. I have put diesel in non-diesel engines before but have yet to put the fuel in the wrong place entirel : )

Just talking it through with you guys so far I think it makes sense. Trip 3 was just shy of trips 1+2. We had double the passengers and double the equipment. Also that 20 or so minutes of WOT didn't help either. I was just hoping that wasn't the norm b/c I can't afford 150/week in gas.

 

[QC]

Re: Fuel consumption...

http://www.boattest.com/boats/boat_video.aspx?ID=1082#Test-Result

 

[NHGuy]

Re: Fuel consumption...

It's not the same weight boat or driveline, but I can tell you that when I run wide open there is considerably more fuel consumed than when I just back it off a little. If I run it at 80 or 90% throttle there's a lot more time and distance in my tank. Maybe you are in a similar situation.

 

[QC]

Re: Heard Rumors AZ has the most Boats.

Re: Heard Rumors AZ has the most Boats.

A few points to consider for marine applications:

1) Fuel rates and horsepower are kind of the same thing. Horsepower goes up, fuel rate goes up.

2) Horsepower against a linear load (propeller) goes directly up with RPM, so the fuel rate does too.

3) Horsepower required goes up rapidly at the highest speeds (MPH and RPM)

4) Engine efficiency suffers at the highest RPM points

 

[metriccrescentwrench]

2) Horsepower against a linear load (propeller) goes directly up with RPM, so the fuel rate does too.

3) Horsepower required goes up rapidly at the highest speeds (MPH and RPM)

Put another way, assume you get 4 mpg at 3/4 throttle, you'll likely only get maybe 3 mpg at full throttle. Once you get past the sweet spot for cruising speed the power (and therefore fuel) required to go faster increases very fast. Consider the fact that you went a little further than your previous time out, you spent a good bit of time at full throttle (burning WAY more fuel), and you had a lot heavier load. Your scenario sounds perfectly plausible.

 

[saxrulez]

Re: Fuel consumption...

Your boat gets about 3mpg at cruise. WOT is going to be considerably less, so probably pretty normal.

Top speed for the Sea-Doo Utopia 205 SE (2006-) is 52.6 mph (84.7 kph), burning 21.3 gallons per hour (gph) or 80.62 liters per hour (lph).

Best cruise for the Sea-Doo Utopia 205 SE (2006-) is 27.8 mph (44.7 kph), and the boat gets 3.31 miles per gallon (mpg) or 1.41 kilometers per liter (kpl), giving the boat a cruising range of 119 miles (191.51 kilometers).

 

[TBGixxer]

Re: Fuel consumption...

Thanks for the replies. I'm gonna watch it my next trip out and see how it does. I just couldn't believe how much more fuel that last trip burned.

 

[ewenm]

Re: Fuel consumption...

plus is your seedoo a jet boat?? i think it is and i also think they use more fuel than a propped boat all other things being equall

 

[H20Rat]

Re: Fuel consumption...

plus is your seedoo a jet boat?? i think it is and i also think they use more fuel than a propped boat all other things being equall

haven't checked on boat test for that particular boat, but most of the newer jets get comparable or BETTER mpg's than a similar equipped bowrider.

A very rough rule of thumb is horsepower/10 = WOT fuel burn per hour. In your case, 320 hp = 32 gallons per hour worse case. (yikes!)

 

[45Auto]

Re: Fuel consumption...

I was just hoping that wasn't the norm b/c I can't afford 150/week in gas.

Might have been worth your while to do a little research on fuel consumption BEFORE you bought the boat ......

If you want to run your boat for 5 or 6 hours a week, covering around 150 miles, it's going to burn about 50 gallons a week.

 

[Home Cookin']

Re: Fuel consumption...

I recall some OMC's back in the 70's with a fuel saver feature; you accelerate then back down, and maintain the same speed with 10% less fuel, IIRC.

For TBGixxer, consider your prop as well. What are your RPM's at top speed, and how does that square with your motor specs? If you are underpropped you will burn out the motor while you are burning up the fuel.

There is also an efficiency factor when you get on a plane, so even when you don't want to go "that fast" get up on a plane then back down to a slower speed while maintaining the plane.

The efficiency factors typically discussed really only pertain to larger motors, not those under 30.

A lot of people here focus on their top end, which in boats, unlike cars, becomes very inefficient. If you like top speed, you will spend more $$ boating. I'm happy to cruise at 30 even though my boat does 40. But that's just me and my style of boat use.

 

[H20Rat]

Re: Fuel consumption...

http://www.boattest.com/boats/boat_video.aspx?ID=1082#Test-Result

Link didn't work for me, kept getting an aspx error from boattest... If it went to it through the site though it worked.

 

[QC]

Re: Fuel consumption...

Link didn't work for me

Weird, goes straight to the chart/results page for me . . .

 

[boat1010]

Re: Fuel consumption...

I go through about 50 gallons of gas just on the weekend. And that is on a pretty small lake. Boating is not a cheap water s port with the gas prices. A 454 plus a 4500lb boat add up to $$$$$ welcome to boating...