Range for Sea Ray Sundancer 260

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BoatingTimbo

Petty Officer 3rd Class
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May 18, 2009
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We recently bought a 1980 Sea Ray Sundancer 260 (SRV260) which has been repowered with a 97 Mercruiser 5.7L and Bravo II drive. Boat has 100Gal tank and a comfortable cruising speed for us is around 25 mph.

What range can i expect from that 100gal tank and what are guys with this or similar boat getting for fuel consumption?

Trying to plan some longer trips for the summer and trying to figure out my comfortable range and etc. for this boat?
 
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RickJ6956

Petty Officer 1st Class
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Jul 18, 2009
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Re: Range for Sea Ray Sundancer 260

You should do your own fuel calculations. Information you may find online wouldn't apply because the boat's power plant has changed from the original.

When you do the calcs use the tachometer to determine how much fuel you're burning in gallons per hour at various sustained RPMs. Keeping a trip log helps you develop these numbers. Speed is irrelevant because it varies with wind, current, conditions, and weight.

Also, the general rule is to use one-third of the fuel to get to the destination, one-third for the return trip, and one-third held in reserve.
 
JoLin

JoLin

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Re: Range for Sea Ray Sundancer 260

Range is highly variable depending on load, water and wind conditions. You need to do your own calculations. You shouldn't plan any longer trips until you have a handle on your consumption. For a baseline (until you zero in on your own) I'll take a stab.

You're probably turning 3400-3500 rpms at 25 mph on GPS. I think 12 gph is a reasonable starting point for that boat and motor with moderate load and decent conditions.

Always remember the 1/3 rule- 1/3 of your fuel going out, 1/3 to get back, 1/3 in reserve in case conditins deteriorate. Fuel consumption goes up dramatically when you're taking wind and waves on the bow.

My .02
 
JoLin

JoLin

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Re: Range for Sea Ray Sundancer 260

Oh- don't try to carry 100 gallons. Consider the tank full at 7/8 to allow room for expansion. A full load of fuel is also a mixed blessing as the added weight raises your consumption.

Having fun yet? :)

Just be very conservative in your calculations until you know better.

Good luck- enjoy the boat!
 
45Auto

45Auto

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Re: Range for Sea Ray Sundancer 260

Best cruise (from Boattest.com) on a brand new Sea Ray 260 with a fuel injected 5.7 is 2.2 MPG at 30 MPH. In the real world, on a 30 year old boat with a 13 year old drive system, your best cruise will deliver less than 2 MPG and your average (including no wake zones, idling, docking, etc) will be in the neighborhood of 1.2 - 1.5 MPG.

As stated earlier, your best decision would be to use the 1/3 out, 1/3 in, 1/3 reserve rule. On a 100 gallon tank, any destination over 50 miles away would probably be pushing your luck.
 
bekosh

bekosh

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Re: Range for Sea Ray Sundancer 260

45Auto said:
Best cruise (from Boattest.com) on a brand new Sea Ray 260 with a fuel injected 5.7 is 2.2 MPG at 30 MPH. In the real world, on a 30 year old boat with a 13 year old drive system, your best cruise will deliver less than 2 MPG and your average (including no wake zones, idling, docking, etc) will be in the neighborhood of 1.2 - 1.5 MPG.

As stated earlier, your best decision would be to use the 1/3 out, 1/3 in, 1/3 reserve rule. On a 100 gallon tank, any destination over 50 miles away would probably be pushing your luck.
Click to expand...

1/3 out, 1/3 in, 1/3 reserve rule is good if you are going someplace where you won't have access to fuel and need to return to your dock on a single tank. Otherwise it's way to restrictive.

If you will have access to fuel along the way you can extend your range out quite a bit. I calculate my range for pump to pump as being 85% of a full tank. For me that works out to be about 100 miles. (50 gallon tank @ 2.5mpg)

For the OP, 1.2-1.5 mpg sounds about right so 85 gallons x 1.2 mpg (always use the conservative estimate) would give a range of about 100 miles with a 15 gallon reserve (about 18 miles). Of course you want to plan your travel so that you never break into that 15% reserve except in an emergency.

I would start with some trips where you can fill up after you've run 50-75 miles so that you can get a solid MPG number to plug into your calculations.
 
JoLin

JoLin

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Re: Range for Sea Ray Sundancer 260

bekosh said:
1/3 out, 1/3 in, 1/3 reserve rule is good if you are going someplace where you won't have access to fuel and need to return to your dock on a single tank. Otherwise it's way to restrictive.

If you will have access to fuel along the way you can extend your range out quite a bit. I calculate my range for pump to pump as being 85% of a full tank. For me that works out to be about 100 miles. (50 gallon tank @ 2.5mpg)
Click to expand...

Yeah, I neglected to mention boating from gas dock a to gas dock b, but I'd still figure 2/3 out and 1/3 in reserve. That 85% thing probably works out okay for flat lake boating, but IMO it's pushing it for more open waters (oceans, bays, Great Lakes).
 
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BoatingTimbo

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Re: Range for Sea Ray Sundancer 260

Amazing feedback and advice guys. Thanks a lot. For starters to be extra safe i'll guesstimate 1mpg and stick with the 1/3, 2/3 rule until we've done a few trips and kept a solid log allowing me accurate data for our boat, average conditions etc. etc.

Is the best way to accurately measure the fuel consumption to fill up before each trip, make note of miles traveled and hours gone (to get mpg & gal/hr.) and fill up again on return making note of gallons put back in the tank?? Eg: 10 mile trip, 5 gallons to fill back up = 2mpg (if i'm lucky)??
 
45Auto

45Auto

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BoatingTimbo

Petty Officer 3rd Class
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May 18, 2009
Messages
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Re: Range for Sea Ray Sundancer 260

45Auto said:
Best way is to use a fuel flow gauge tied to a GPS for real time mileage measurement. That way you can optimize your speed and trim for the best mileage. You can easily make a 10% or 20% fuel savings. At 1 or 2 miles per gallon, that will easily pay for itself if you do much cruising at all.

Lowrance has some nice add-on fuel flow gauges:

http://www.overtons.com/modperl/product/details.cgi?r=view&i=380054&aID=601Q6&cID=FROOGLE_380054
Click to expand...

Ya, that would be great. What/How is it connecting and measuring MPG. connected to my GPS (how) and fuel line b/w tank and fuel filter??
 
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