Fuel Consumption - OffShore Boats??

SRT10VENOMOUS

SRT10VENOMOUS

1800HP Club. And climbing
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Hey does anyone know a good rule of thumb or have experience with fuel consumption for some go fast boats??

I'm looking at some 38 to 47 footers " Gofast style" and was wondering what the fuel consumption was.

Typical packages would be 2x 525s or 3x 525s

then you step it up to the supercharged duals or tripples.. aprox 700hp each

anyhow on that note, does anyone know how to figure out the fuel usage..

Thanks,
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Calculating Fuel Consumption
By Brett Becker

Figuring out fuel mileage on a car is simple. Fill the tank completely, jot down the current mileage and drive until the tank is near empty. At the next fill-up, note the miles traveled and the gallons of fuel it takes to refill the tank. Then divide the number of gallons of the second fill-up by the miles traveled.
It's a different story with a boat. Miles aren't easy to measure on water, so fuel consumption is measured in gallons per hour. You measure fuel efficiency in pounds of fuel used per horsepower developed per hour. The pros call it "brake-specific fuel consumption." This makes it important to know that gasoline weighs about 6 pounds per gallon.
On average, an in-tune four-stroke gasoline engine will burn about 0.4 to 0.45 pounds of fuel per hour for each unit of horsepower. Likewise, a well-maintained two-stroke outboard burns nearly 0.6 to 0.8 pounds of fuel per hour for each unit of horsepower it produces. These figures apply to carbureted and fuel-injected engines, but not to direct-injected engines such as Mercury's OptiMax and OMC's FICHT models.
Confused yet? Keep in mind that these formulas apply when the engine is making peak horsepower, which usually is near wide-open throttle. Fuel consumption will be decreased at cruising speeds. Also remember that newer engines with loop-charged intake systems, fuel injection and direct injection will yield higher fuel efficiency than older, cross-flow fuel systems that were manufactured as late as 1990. Cross-flow systems are antiquated and wasteful compared with the technology available today.
To apply these formulas to your boat, just plug in its horsepower rating and multiply the top, then divide the result by the bottom. For two-stroke engines, another way is to take the total engine horsepower and divide it by 10. As you can see, this formula is simpler to calculate and easier to remember. You don't even need a pencil and paper. The result represents the approximate gallons per hour the engine will burn at wide-open throttle. For example, a 150-horse engine will use about 15 gallons per hour. Though these figures represent averages and can vary from 10 to 20 percent, they'll put you in the ballpark so you can plan a long-distance cruise.
 
I'm a little confused......if you can afford a boat like that then who cares about fuel consumption. Just fill it up and go.:dontknow::D
 
Well it depends a lot on the hull. Fountains tend to be more fuel efficient than some other hulls. Around 500hp I'd figure cruise at around 20gph cruise (3500 rpm) per engine. At wide open I don't even have a guess other than it would be staggering.

Truth is if you are seriously looking at a boat like this and fuel consumption is a concern you need to think more on this. Trust me, the fuel is a relatively small percentage of the total on a boat of that size.
 
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Hey thanks for the formula and very simple to use..

500hp 50gph
1000hp 100gph..
at max rpm...


looks like I will continue focusing on the Twin 525 set ups, I got distracted with some of the prices on these bigger boats with triples but looks like the extra hp will really put a damper in the check book...

And the famous " if you can afford the boat don't worry about the gas" well were not all multi millionaires in our 20s... we'll I'm certainly not,, But I do have a string business and I could afford one of these boats but want to make sure its " reasonably practical for what you get" vs a 600gph turbine engine...


or another look at it
. I'm looking for a new dodge pick up.. should I get the base model with 200hp or the hemi or the viper enigie...

Ya cant really say well if you can afford the truck don't worry about the fuel millage.. when they are all drastically different.
 
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Scrambler1 said:
Well it depends a lot on the hull. Fountains tend to be more fuel efficient than some other hulls. Around 500hp I'd figure cruise at around 20gph cruise (3500 rpm) per engine. At wide open I don't even have a guess other than it would be staggering.

Truth is if you are seriously looking at a boat like this and fuel consumption is a concern you need to think more on this. Trust me, the fuel is a relatively small percentage of the total on a boat of that size.
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Any idea if the tunnel hull is a better way to go to try to increase gph??

And it's not so much worried about the consumption its more along the lines of trying to make an educated estimate at what I will be getting into. And what engine will suit my needs best...



And believe it or not boats like this now days are well cheep, especially if they are a few years old...
 
SRT10VENOMOUS said:
Any idea if the tunnel hull is a better way to go to try to increase gph??

And it's not so much worried about the consumption its more along the lines of trying to make an educated estimate at what I will be getting into. And what engine will suit my needs best...



And believe it or not boats like this now days are well cheep, especially if they are a few years old...
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They look like incredible boats. Really look like fun. Good luck with whichever you chose.:congrats:
 
there are some nice Viper powered boats out there. Ilmor has a 710 h.p. NA

:rock: :rock: :rock:

where do the fishin poles go?????:dontknow: :dontknow: :dontknow:
 
from the article i read, thats a 1.2 million dollar RV/boat
 
I can't seam to find any boat with a viper engine at a reasonable rate, I'm not looking at new as they are 5x more than the cost of a nice used boat.. It sames all the Ilmore boats are gettin outa my ballpark.
 
SRT10VENOMOUS said:
Any idea if the tunnel hull is a better way to go to try to increase gph??

And it's not so much worried about the consumption its more along the lines of trying to make an educated estimate at what I will be getting into. And what engine will suit my needs best...



And believe it or not boats like this now days are well cheep, especially if they are a few years old...
Click to expand...

Tunnel boats are almost always more efficient for their length. You trade some ride quality and a usable cabin for it though. Priorities.

Oh believe me I know what you are saying about the prices of boats right now. A lot of people are giving away the gas pounding toys. Good time to buy if you can throw down the cash.

I recently, well 3 years ago, moved from trailerable outboard fishing boats to my first live in the water diesel cabin boat (38ft.). I knew that the fuel was going to be more but really going from gas to diesel took some of that edge off (diesel is cheap on the water compared to gas). The biggest adjustment has been the maintenance... two engines and a generator (water pumps, oil changes, fuel filters, belts, electronics, etc), raw water pump, fresh water pump, A/C systems, head, two different electrical systems to maintain, refrigerator, ice maker, etc. A boat of this size, especially if it lives in the water or on a lift, is constant. Plan on a couple hours a week to keep it looking good and operational.

Not trying to rain on your parade just want to make sure that you don't end up being one of the myriad of boats parked around marinas going to ruin because the owner doesn't have the time and doesn't want to spend the money to properly maintain the boat and then gets fed up with it because it always has a problem when he wants to take it out.

I've always liked go fast boats... good luck!
 
Thanks for the info Scrambler1,, Ya I'm trying to find something low maintenance as possible, been finding some nice 36 footers out there 7600lbs or so , so they would not be hard to tow, And I think I would take it in and out of the water every use to keep it from rotting in the salt.. And from what I can see so far is the 500 hp engines 525s whatever seam to go forever with out a full rebuild.. VS the 700s, 1075s which get about one summer before rebuilding at 10k a pop... Looks like if you keep with the smaller HP engines they can run like 800+ hrs no problem, with out fully rebuilding them anyhow...

I would strictly be using it on weekends for 5 months of the year so say 1 day of the weekend 6hs of run time per week.... should keep the maintenance down a lil anyhow...
 
viperhauler said:
what is your ballpark?
Click to expand...


Well I don't want to lease or finance unless I absolutely have to, So I'm looking at used rigs around 100k.... if I went much more than that Id have to finance or lease then hell I'd go for a real bad ass boat but don't need another payment around here...

From what I can find on boat trader/ ebay/ etc... there are plenty of boats about 10 yrs old in great shape in that ball park ,, which were once 500+ range...
 
"Gofast" boat fuel consumption is measured in GALLONS per MILE if that helps put things into perpsective for you. . . ;)

I've always wanted a fast boat. There's a badass murdered-out Fountain that floats around here. (It even has a tiny red pinstripe down the side!) And, it's even for sale! You can always hear it before you see it. In all honesty though, I wouldn't want that as my primary mode of aquatic transportation. I enjoy wakeboarding, skiing, and (attempting) to kneeboard way to much! I've had my boat up to 52(ish), which is plenty fast enough for me (for the time being). Maybe one day I'll put a fuel (economic) LSx engine in my boat.
 
viperhauler said:
http://www.boattrader.com/listing/2000-Donzi-33-ZX-95056107
http://www.boattrader.com/listing/2002-FOUNTAIN-EXECUTIONER-95456840
http://www.boattrader.com/listing/2002-FOUNTAIN-35-Lightning-95230638

i could do this for days....which i'm sure you have been....do you have any idea on which brand you're looking into????
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Ya exactly what Ive been doing for well good part of 2 months.. Just watching and waiting and learning and hoping for a steel to come up... I may have found one though, An old buddie of mine has a 36 Formula fastech 2003 with twin 500s ,,, says I can have it real cheap.. But I know hes hard on stuff so I wanna check it out first to see if its still in one piece..
 
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