Fuel Consumption CC28 with Volvo D4's

[Marty Color]

First of all I'd like to say "thanks to all involved" for offering this wonderful site to share information. My brother and I are the proud owners of a like new 2006 CC28 powered by Volvo D4-260's. We just returned from an offshore trip where we traveled a total of about 150 miles. (Actually the Volvo gauges said that we went 148 miles.) We left the dock with a full tank and upon our return filled the tank with 154 gallons of fuel.

The first 60 or so miles were at about 25 knots with an average engine RPM of 3050-3100. We slow trolled (mostly on one engine) for about a total of 20 miles and our return trip was about 40 miles at 20 knots and 20 miles at about 10 knots.

Anyone have any thoughts or opinions on our fuel mileage?? We were hoping that our CC28 would have more range..?? Is basically 1 mile per gallon what's to be expected from this setup??

Thanks to all for any input provided.

PS: the boat does NOT have a tower and the engines have about 50 hours on them. We left the dock with 3 adults ( all slightly overweight,) fishing gear, 500 pounds of ice, a full water tank and a full fuel tank.

[Split Decision]

That sounds a little low on the mpg. Backman would be the best member to answer that question. He repowered his with those engines last year and has about 300hrs on them so far. I think his mpg was better than that though.

[code blue]

d4's

that sounds right to me. I have the same setup with a tower 05 model. I only run and gun at most 20 miles and troll all day (the fish are closer in hawaii). At that speed the burn for me is about 22 gph. I then troll at 8-8.5 knots burning 5-7 gph. So on days where I do not run far and troll all day because it is so rough I can burn as little as 60 gallons, but I have burned close to 100 gallons fishing 12 hours and running hard for 2. So running hard for 80 miles I would figure you are burning about 80 gallons.
I am not sure why you are trolling with 1 engine, what does your evc screen say you are burning? Are you maximizing your trim tabs? I also try to move the ice weight forward in a fishbag to better balance. This boat all loaded down is heavy! What is your top end speed? How is your bottom paint/growth? Do you have a large ferring block transducer?

[Marty Color]

Thanks for the reply on the fuel consumption

Regarding the "one engine" question; we were slow trolling live baits and wanted to go slower than two engines would allow even at idle.

No bottom paint at all... we had a trailer built and pull it out of the water each time we're done fishing.

No big blocks on transducer

THANKS for the help... I'm hoping to achieve some better mileage to imrove my range.

[Bullish]

I have a 2002 28 with a tower and volvo kamd's. I expected to get more mileage out of my fuel too but I only average about 1 mile per gallon at 23-25 knots. Since I run 75 miles to the canyon a few times per year, I am cutting it close if I plan to troll for more than six hours.

An extra 20 gallons would give me piece of mind so I have to decide between the cost of a bladder or carrying a few fuel cans in the future.

[backman]

You should get 1.25 to 1.33 nmiles/gallon

If you run the boat at 25 knots/3000+RPM.

Today I burned 121 gallons - I ran out ~60 miles @ 25-26 knots into sloppy 3-4' head seas/2:20 of time/3050 RPM. I came back at 3050 also/26 knots/3-4' following seas and a lot of pounding and yawing/2:25 of time.

I trolled 6.5 hr's at 1280 RPM. My math after 500 hrs says 3000 RPM/25 knots is 20 GPH, 3070 RPMs/26 knots/21 GPH, 3150/27 knots is 22 GPH. Trolling at 1300 RPM is ~4 GPH.

I regularly ran day canyon trips last year ~90 out/90 back and troll for 8 hours. That equated to 7 to 7.5 hr's running time and 8 hr's troll time and would burn 170-180 gallons. (7*21+8*4)=~176 gallons.

I take my chances on day trips; for overnights I carried a 33 gallon Nauta which started leaking last year. This year I think I am going to emulate a guy I saw on this site who carries 6 5 gallon plastic fuel jugs. The bladder and pump are OK but have a variety of P.I.A. issues associated with them, specifically stowage and power connection. I'm going to experiment with 6 jugs; carried on the outboard side of each engine and see how that works out.

ON your milage - the boat and engines combo are most efficient in 2 ranges - idle -> 7 knots and 24-27 knots; you want to either run it at hull speed or the designed planing speed to get the best fuel efficiency. 10 MPH is probably the worst place to be on the power curve for fuel efficiency.

I can run 20 nmiles/hr at ~2750 RPM and burn 17 GPH - it will get me through most anything but its not fuel efficient.

[TwinFin]

Jugs

Hey Larry.

I'm still trying to talk myself into a way of upping my fuel capacity by 30 - 50 gallons.

I'm close to buying a bladder but I saw your post. By outboard of the engines - are you meaning in the engine compartment??? You must have more room with your D6's than I have with the 300's. Or do you mean along the gunnels outside the enclosure? I'd be scared to store fuel (or much of anything else) in the engine compartment for fear of it pounding loose. How you planning to secure the jugs in either location?

I have thought about storing full jugs in the cockpit on the way out, then putting the emptied jugs on my swimstep for the rest of the trip. I would not want them on the swim step full - I had a bracket bolt shear off for unknown reasonslast season - with no real weight ever being back there.

Steve

[backman]

Jugs were worse

First fuel consumption.

FRiday:

102 nmiles out - 4 hr's run/26 knots - troll 8 hr's
Sat: troll 6 hr's, 84 nmiles back 3:20 run/27 knots

Total fuel burned - 184 gallons - 7:20 run @ 20 GPH - 146 gallons 14 hr's troll at 3 GPH = 42 gallons - as close a guestimate as I can get/ D4 gauges said more or less the same.

Jugs sucked and had a lot of drips and leaks; it was easier to stow them on deck on the way out - 3 in one fishbox; other 3 lashed to the tower leg - this made for much better weight distribution than a 30 gallon bladder. I could not safely get them in the engine room either, empty or full and ended up lashing them to the foredeck rail after they were emptied. They bounced and banged all trip and one oozed out the vent. It was not a rousing success.

Transferring fuel from jug to fuel tank was a 2 person job, one to hold and flip the jug outboard; one to align the spout at the start. I made a mess with the 1st 2 solo before going to a 2 person approach. Xfer time was probably 1-2 GPM w/ jugs where the bladder and pump was probably 4 GPM.

[TwinFin]

Mileage - KAMD 300's, full tower.

Went back through my log book. I have not done anywhere near as good a job as Larry has at estimating burn rates at different speeds & RPM's but my bottom line is clear. On tuna trips (45 - 75 miles out) the best I seem to be able to claim is an average for the trip of 1.2 MPG.

Larry:
So do you recommend I go ahead with the bladder? How big? Were you able to secure yours on the deck such that you felt safe it was not going to slide around and break loose? Could the pump have been run using a simple cigarette lighter connection at the helm or was the current draw large enough that you had to open the hatch and connect directly to your battery?

Steve