R-29 fuel range

[kskogerson]

Anyone out there with the exact range on a R-29 with the new volvo D-4 say at 8 knots?

 

[walldog]

The exact range will always be a moving target based on what it takes to maintain 8 knots. Current and winds vary and will make a huge difference in power required to maintain a speed. I imagine the Volvo is like the Yanmar and is networked to the chart plotter screens. On your engine and navigation screens, the range remaining can be selected to show. I find this to be very accurate on my 27, but as I say it is a moving target and will vary greatly. Any charts or public specs that indicate range will be based on a no current situation, which is unrealistic to expect in actual conditions.

Set your fuel to all tanks full, set your speed to 8 knots and you will be able to check the range remaining. Hold the speed over a period of time and you will see the range vary as you adjust power to maintain 8 knots. Or just leave the original throttle setting and the range will vary as the speed varies based on current changes.

Hope this helps.

 

[circusmar]

+1

Depending on wind and current our nmpg can vary by over 10% one day to the next. Keep in mind speed through water does not equal speed over ground or distance made good. Your progress toward a destination will often be a vector sum...

Thus the rule of thirds and why a 100 gallon tank can start to seem pretty small.

 

[Todd]

Real rough estimate.
R29 at 8 kts will require 3.5 to 4.0 gallons per hour.
120 gallons would be 30 hrs or 240 miles.

Slow down to 6 kts and you get over 800 miles on a tank of fuel.
Its about the trip not the destination.

 

[NewMoon]

FWIW,

Cruising 95-98% of the time at 6 knots, our fuel mileage stays pretty consistent: between 3.9-4.6 nmpg, but staying most of the time between 4.0 and 4.3 nmpg, despite varying sea conditions and currents in SE Alaska. This is over maybe 20,000 nm of slow-speed cruising. On plane at 17 or 18 knots, we get only 1.75 nmpg.

We're a heavy 26-footer (11,000 lb on the water with full tanks), running a Volvo 44 diesel with duo-prop sterndrive. We calculate mileage for each fill-up (typically 50-80 gallons of our 110-gallon tankage), based on the chartplotter's record of distance traveled over ground.

So for us a max safe range, unless we decide to power up to planing cruise speeds for more than a few miles, is 300-350 nm. In theory we could travel 400-450 nm before sucking fumes.

We can easily push our slow-cruise speed to 7 or 7.5 knots, but our mileage drops significantly, going as low as 3 nmpg. If you travel at 8 knots, I'd expect your mileage would be quite a bit less that if you stick to 6 or 7.

 

[kskogerson]

Thanks for all. I'm considering a trip down the baja on the pacific side in my R-29 and need to make 450 miles from Ensenada to Turtle bay...the next stop for fuel. I've done this before but in a 50 footer...different parameters obviously.
I just don't know if this is possible with 120 gallons without bladders.
The seas in November are favorable with a following sea and usually no weather issues.

 

[walldog]

Thanks for all. I'm considering a trip down the baja on the pacific side in my R-29 and need to make 450 miles from Ensenada to Turtle bay...the next stop for fuel. I've done this before but in a 50 footer...different parameters obviously.
I just don't know if this is possible with 120 gallons without bladders.
The seas in November are favorable with a following sea and usually no weather issues.

Not enough reserve for me. Even at 3 NMPG with 150 Gallons of fuel...you would need every drop with no reserve. I would be surprised if you would do that well trying to make 8 Knots.

 

[Spinner]

A new R29 with the Volvo D4 carries 150 gallons of fuel, not 120. The older models had two tanks: a 120 and a 30. Does that help?

Sue P
Spinner

 

[ozoner]

I think I am with walldog... That is cutting it way too close, and not allowing margin for weather or detours.

I think I would want at least another 50 gallons on board - that gives you 100 extra miles of range assuming 4 gallons an hour at 8 knots. That's 10 plastic jerry cans or four 12 gallon Attwood tanks - not incredible convenient, but probably doable. (Too bad no-one rents bladder tanks - they are pricey to buy).

And of course, don't forget to throw in some stabilizer and bring your Baja filter.