fuel tanks

raymondean

Cadet
Joined
Jul 4, 2014
Messages
13
Hello everybody,
I have an 09 bayliner 185, 18.5 feet. It has an 3.0 liter, with mercruiser alpha 1.
When we take it out on the lake, with 2 people, and maybe 300lbs of fishing stuff etc, it seems to really love gas. I have a stainless prop, at 19 degree pitch. My wot is 45 at 4800rpm(according to mechanic and manual.)
Anyway, for a full day, I will easily go thru 20-25 gallons, and most of the time, we are only going about 30mph or so. I was thinking of adding a 20-25 gallon tank, but don't really know how I should do it. I figure I will need to put it centerline and low, more forward.(I have 2 extra batteries hooked up in boxes under back seats.) and know that too much weight in back causes stability problems. My hope was, that I could gravity feed into main tank, or set up secondary to pump into primary as primary level decreases. I am the kin
 

raymondean

Cadet
Joined
Jul 4, 2014
Messages
13
Somehow, the rest of my post fell off. Anyway, Any suggestions would be greatly appreciated. Thanks
 

Watermann

Starmada Splash of the Year 2014
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Jan 12, 2013
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13,747
Adding fuel capacity by the way of a secondary fuel tank would be more than a weekend project. You would need to remove the decking and flotation foam to add say a bow tank. Then you would need another filler spout, vent, switch over fuel line manifold and way to switch the fuel gauge sender too. A better option would be to add a larger main tank but it would also mean gutting just about everything from the center of the boat to get to the tank. I don't think it would be feasible to rely on gravity and being it's an 09 you may need another fuel pump too, maybe an electric. It can be done but I think refueling would b a better option considering the amount of work and expense. You could also have some extra fuel in portable cans in your vehicle at the launch if the lake doesn't have fuel available at marinas.
 

Bondo

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Staff member
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Apr 17, 2002
Messages
70,465
Ayuh,..... For a little boat like that, I suggest ya leave that 200 lbs of gas on-shore, 'n just refill the current tank,....

Yer fuel mileage will be worse, with the added weight, no matter where ya put it,...
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Ayuh,..... For a little boat like that, I suggest ya leave that 200 lbs of gas on-shore, 'n just refill the current tank,....

Yer fuel mileage will be worse, with the added weight, no matter where ya put it,...

Yep, my 2nd on this!....more gas=more weight=worse mileage....your boat is just too small for the extra fuel!....
 

thumpar

Admiral
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Jun 21, 2007
Messages
6,138
How big is the tank on it now? I have a 40 gallon and can go for at least 2 good boat days. Maybe you have a carb/engine problem.
 

GA_Boater

Honorary Moderator Emeritus
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May 24, 2011
Messages
49,038
How big is the tank on it now? I have a 40 gallon and can go for at least 2 good boat days. Maybe you have a carb/engine problem.

Bingo! When I saw 20-25 gallons of gas used for what sounds like a day of fishing, it didn't sound right. Maybe we need the rest of the first post?

Here is the 2009 BL 185 w/3.0 MC performance data from Boattest - http://www.boattest.com/partners/par...id=1860&p=0&s=
 
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JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
My 19' Stingray has the same engine. My 19 gallon tank is good for a day and a half. Typical Sunday usage is 10 gallons. We leave at about 9AM and don't come home till 7 or 8 PM. I don't think I ever used more than 12 gallons in a day. Sounds like an engine issue to me as well.
 

airshot

Rear Admiral
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Jul 22, 2008
Messages
4,219
Well lets see here....30mph means you are probably burning around 5-6 gallons per hour which is probably pretty close to normal for that engine. perhaps going at a slower speed or stop and enjoy the scenery more often. If you are running at a constant 30 mph with a 25 gallon tank you have only about 5 hours run time. When I spend the day cruising my average speed is much less and we make frequent stops to enjoy the scenery or to fish. And on avg I use around 8-10 gallons per trip, however on a long journey where I am running on plane then I will easily use 20 gal of fuel. What is you definition of a day on the water? How much time movin and how much time sittin? As I said about 5-6 gal per hour at 30 mph limits your time on the water. As the others have said adding another tank will increase your fuel usage.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
I usually cruise at around 30-35mph in a much heavier boat. A normal day is around 7 hours and a 35-50 mile trip during that. I don't even use that much fuel unless I want to play with the throttle.
 

shrew

Lieutenant
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Dec 29, 2006
Messages
1,309
Year/Make/Model: 09 Bayliner 185, 18.5 feet.
Engine/Drive: 3.0 liter, with Mercruiser Alpha 1.
Load: 2 people, and maybe 300lbs of fishing stuff etc,
Prop: Stainless prop, at 19 degree pitch
WOT: 4800rpm (according to mechanic and manual.)

Time: A full day,
Fuel Burn: I will easily go thru 20-25 gallons/day
Average Speed: ~30mph
...
It seems to really love gas.

I don't believe there is enough information to truly address the 'problem'. How many hours are you running at approximately 30mph in order to burn 20-25 gallons of fuel? How are you running the boat. In other words, do get up on plane and run for 2 hours like a cruiser would, or are you on and off plane like a fisherman or when skiing/tubing?

4800 rpm is Mercruisers publish Max. RPM @ WOT. You would need to actually get the boat at WOT, and trimmed properly to determine what actual WOT rpm is. This will determine whether your propped correctly. That may have some impact on fuel burn, but probably not significant. A tune-up might as well. However, that isn't really the point of the post. (My apologies, I've digressed)

I'd be interested in hearing concrete numbers. Fuel burn and the number of hours of run time along with the water conditions and type of use. The problem is, "It seems to really love gas" is relative. 20-25 gallons/day isn't clear. If that is one hour of run time, then yes, that is excessive for that boat.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,414
shrew
I'd be interested in hearing concrete numbers. Fuel burn and the number of hours of run time along with the water conditions and type of use. The problem is, "It seems to really love gas" is relative. 20-25 gallons/day isn't clear. If that is one hour of run time, then yes, that is excessive for that boat.

I can sympathize with the guy. My first boat, a 19' Citation had a Merc. 3.0 with a 40 gallon tank. Fuel capacity put a serious damper on my productivity. No 20 mile runs to a "hot bite" for me....

Here was a pretty typical day for you to "calculate"....... 1.2 mile out the creek at idle, against 3 kt. tide. Get to bouy, throw down the throttle, run 10-12 miles at 3800 rpm, in 2' seas against a 12 kt. wind. Troll at 900 rpm for 6-7 hours before packing it in for the day. Run 18-20 miles back to the dock at 1800 rpm with a 2' following sea, 10 kt. wind and a 4 kt. tide pushing back at you.

In the 3 years I owned that boat I probably made that trip 150-200 times. I keep fuel records for taxes so let's see how close you get.....lol


I've run a Flow Scan system on my present boat for the past 5 years. You can throw the factory's "down hill", "wind at your back" data out the door.

Example: The cruise speed on the Grady is 27 kts. Depending on conditions, consumption at that speed ranges from 0.96 to 2.96 mpg. Trolling, your looking at 0.8 to 1.2 GPH depending on the tide conditions.
 
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