Fuel consumption this past weekend for the old 400DA gasser...

[Skuza]

Finally after all these years I did a trip this weekend and topped off before and after and here are the results:
1998 400DA 7.4L Horizons
22,500lbs dry weight boat.
Full fuel and water. (and fridge)
Flat lake, 80 degrees.
Engine sync used the whole way along with autopilot for straighter course.

45 mile round trip.
61 gallons premium gas used costing $283 at $4.61 per gallon.
Ran 3,400rpm averaging 26 mph/23 knots.
Total travel time ~55mins.
Fuel burn: 33gph
.74 miles per gallon.
$6.29 per mile.

Anyone else with a big gasser wanna chime in so I can compare the data?
Little worse than I was expecting but it's probably on par. I figure slowing down to 3,000-3,200rpm may cut down the burn and slow me down a bit. Just wonder how much better burn I would realize at the lower rpm's. I've been on here for the miles per gallon arguements too but where we boat there are rarely large enough waves/currents/winds to have a major impact on the numbers.
I'll also add that the boat has never had the plugs & wires changed and the bottom only has slight algae scum.

 

[rondds]

here's my numbers with carbed versions of your engines. this was a trip from Brick, NJ to Beach Haven, NJ to Atlantic City, NJ, then back up to Brick, NJ. approx 110 miles consisted of inland ICW travel, with two ocean runs of ~12 miles each. the ICW is riddled with no-wake zones and there was one 20 minute stretch where i ran at 1400RPM b/c of a hot engine. the numbers are consistent with what i have been clocking for over 4 years now with this boat. Floscan provided consumption, GPS provided moving time and miles travelled. this boat is 16,500# dry but offers considerably more wind resistance than yours.


133miles, 9hours, 220 gallons, 24.44gph, 0.61mpg, avg. speed = 14.78mph

 

[HIFI]

Finally after all these years I did a trip this weekend and topped off before and after and here are the results:

45 mile round trip.
61 gallons premium gas used costing $283 at $4.61 per gallon.
Ran 3,400rpm averaging 26 mph/23 knots.
Total travel time ~55mins.

This is the part I am not following. . . If your total travel time was 55 minutes at an average of 26MPH you could not have covered a 45 mile round trip. That speed for 55 minutes covers about 23 miles.

 

[osd9]

If you traveled 45 miles in 55 minutes (run time) that's over 46 MPH...something is wrong with the numbers....

 

[sbw1]

My 37 SR Express used to get anywhere from .55 to .77 mpg at 3500 rpms. Speed was 23-26 knots depending on sea conditions and boat weight. Your mpg look pretty good to me.

 

[RollerCoastr]

Some of the numbers are per leg, some are total... easy enough to read between the lines.

At the end of the day Skuza, your results are respectable. Don't slow down. She'll actually consume MORE fuel by going too slow, even when you're technically "on plane".

My cruise habits are very close to yours, as is my consumption data. Looking back, I wish I had invested in flow meters from the onset and eliminated the guessing and bad advice from people who "like to stay out of the secondaries" or have smaller, differently weighted boats. That thinking doesn't apply to a big, stern-heavy, F.I. boats like ours.

On my first long trip on the 400, I went nearly all the way up the coast of Michigan, at about 3100 RPMS and of course, with lots of tabs. I was so sure that I'd see that fuel pump shutoff early. (not even .6) ugh

A few other things:

- if you don't need water for your own use or "ballast", don't carry it.
- premium fuel? like 91 or better? I doubt that was a benefit.
- time for a tune-up. She's treating you well - return the favor.

 

[osd9]

MPGs (.74) look fine.......the distance traveled (45miles) in the time stated (55 minutes) doesn't.

 

[Skuza]

Sorry I did not clarify the travel and distance covered better. 21 miles took me ~50-55 mins. Total distance to and from was approx 45 miles. The trip back had a short scenic route added.
Glad to hear the numbers are common among other gassers. I too have heard the efficiency at higher rpm's arguement. Slowing down may save a bit of gas but the efficiency goes down along with speed. I would rather know I'm going at the fastest, most efficient speed.
Premium is the only fuel they are selling at our marina these days and just figured I'd share EVERY detail. These aren't turbocharged, high compression engines. So just as with cars it will add very little if any performance gains.

 

[PlayDate]

Those are very good numbers. You should be pleased. The rpm seems high verse gph but that may be more of a function of your props size/pitch. I am a big fan of fuel flow meters on these boats because they really pay for themselves by maintaining the right balance of fuel/conditions/speed.

Guessing as Rollercoastr mentioned, just doesn't cut it with today's fuel prices.

In regards to premium fuel.....a reasonable comparison would be a chevy truck pulling a trailer up a 30% grade.........all day long. What you don't want in those conditions is a misfire or detonation. That activity will destroy your engine which is why most marinas sell only mid-grade or premium. Think about the physics involved and it becomes very clear that marine engines required higher octane to operate properly.

-John

 

[dgrumm]

My 400DB with 7.4l carb engines runs 0.6MPG consistently. Doesn't seem to matter if I run 18MPG or 23MPH, it still burns about the same. The only factor seems to be the wind. I installed Lowrance fuel flow meters.

 

[Pseudomind]

My comments from a previous post located here

380 DA

Using auto pilot for most of the sea portion. I do not think these figures overall are to bad given conditions

:thumbsup:

I have not figured the exact distance using a compass and chart, but just by measuring on a map using a map scale, the time was around 7.5 hours.

I now have my 2002 Sea Ray 380, Saturday was a pretty good trip, a bit rough at times, (2-4 foot seas and rain) Going out of Ponce Inlet, about 11 miles South of Daytona was a good hull test, 8-10 foot breakers until we got pass them. Left Halifax Harbor in Daytona at 11:45 AM and was in my slip located off of the St. John's (About 20 miles from the sea, slip is actually located on the Ortega River) by 7:30 PM

Used around 32 GPH (240/7.5) @ mostly 3800 RPMs which was not to bad, considering the seas. A good speed estimate would probably be 18-19 knots, some portions were 21-22 knots at the same RPM's, sea dictated speed.

Most of the trip was about 5 miles offshore from just about 11 miles south of Daytona Beach to the mouth of the St. Johns Maybe 110 miles total

Probably total at 32 miles slower cruising speed (No wake zones) ICW, ST Johns River, etc.

Maybe 142 statue miles in total for the trip 239.8 gallons to fill up or .583 gallons per mile.

 

[mrsrobinson]

What does everyone use to determine miles traveled, charts alone or the trip readings on a GPS, or something else? I notice everyone states mile per this/that...I assume this is land mile and not nautical miles?

I have never checked the miles per gallon, only gallons per hour. On a typical trip on our 330DA, loaded, 2-3 no wake zones (5-10 mins each) we burn 23-25 GPH running at 3300-3400 RPMs, 23-26 kts. I try to plan the longer trips, 1 hour+, to run with the current. It makes a big difference.

 

[osd9]

What does everyone use to determine miles traveled, charts alone or the trip readings on a GPS, or something else? .......

My main onboard Raymarine navigation electonics [chartplotters (RL80CRC and RL70CRC) , GPS (RN300) and ST60 (speed/temp/trip)] have many features, however, the one feature they do NOT have is an 'accurate' way to record miles traveled. I keep my old reliable handheld Garmin GPS 48 with WAAS antenna as both a backup GPS and a reliable way to record my distance traveled.

The newer Raymarine C and E series stuff records distance traveled.

 

[rondds]

i re-set the trip tab each time i go out. it tracks miles travelled, moving time, stopped time and overall time elapsed from the time you hit re-set. i also hit the totalizer switches on the floscans at the same time i hit the re-set on the chartplotter. then i use the calculator in my cell phone! (we dont need no stinkin' smartcraft!)

 

[dgrumm]

I made an excel chart with GPH down the left column and knots across the top. Basically, if my knots are higher than my GPH (per engine), than I am doing good (ie. 19knots and 17GPH per engine is good MPG for my boat).

 

[rondds]

dave, those are pretty good numbers. i use mph b/c it makes the calculation to MPG simpler. MPH/GPH = MPG. the closer you are to 1mpg on larger heavier boats, the better you are. difficult to achieve on gassers unless you are at displacement speed. folks with single outdrives are probably cruising at well OVER 1 mpg. ah, i remember those days...

 

[osd9]

...... the closer you are to 1mpg on larger heavier boats, the better you are. ........

I average right at 1.1 sMPG....on my larger heavier boat. I prefer 'not' to be closer to 1.0 sMPG....:grin:

 

[rondds]

show off! :smt013

 

[gerryb]

I made an excel chart with GPH down the left column and knots across the top. Basically, if my knots are higher than my GPH (per engine), than I am doing good (ie. 19knots and 17GPH per engine is good MPG for my boat).

I do the same calculation frequently when out on the boat. I leave the smartcraft guage on one engine set to GPH, and double it mentally to account for the other engine which is usually at the same RPM. Then I look at the GPS speed display... and it the speed is 1.5x the gph, I'm doing OK and nicely on plane. if they are about the same, I know i'm leaving a huge wake and wasting gas.

 

[thebig4-0]

This time last year I gave my father my Four Winns 267 Quest and moved up to a 1995 Sea Ray 400 Express Cruiser with twin 7.4 L / 454 Merc's (carb's obviously being a 1995). The boat was purchased from Scott Hossack at Hideaway Yacht Sales in Harrison Township, MI. I highly recommend Scott as an honest and straightforward sales guy. I'm a salesman so I appreciate his approach.

Anyways, I had Ron at First Mate Marine do all of the mechanical, except a basic tune-up and oil changes that I did myself. Ron made sure that the running temps were exactly in spec before I left to bring it back to St. Catharines on Lake Ontario, among other things, which took some work, including replacing one of the thermostat housings. (By the way - Ron is absolutely awesome - knows his stuff and doesn't charge you an arm and a leg!!). The result of tuning the boat up and using my spidey senses to find the "sweet spot" at a cruise seemed to really help me, because on a three day trip from Lake St. Clair, through the Welland Canal, to Lake Ontario yielded a 28 gph fuel burn at a 23.5 mph cruise. (GPS speed used to calculate using a Raymarine C120 plotter).

We were about a half day behind a rain storm, and my wife and I had water flat as glass the whole way home (May 24th weekend 2010). That helped with the fuel burn, but we also had some foggy stretches here and there, and some slight headwinds here and there, etc. I had never run that boat (or anything bigger than 27 feet for that matter!) before, and I never trust a fuel gauge in a boat, so we topped the tanks several times by the time I pulled in to Ashtabula Ohio to fill up. By then, the fuel burn was so predictable I told the guy within 5 gallons what we'd need on a half full tank and I was right on the money. I did not include the Welland Canal so the numbers are a good indication of a trip that is 95% set at the same cruise speed, save for docking and some traversing of harbours like Ashtabula and Sandusky, etc.

I have averaged the same fuel burn all last season on trips, so I don't know why people are showing much higher fuel burns on this forum(?). Maybe I just got lucky on this one!

I never had a chance to calculate fuel burn at a much lower rate of speed because the lake always seemed to whip up half way home, and for the sake of comfort I'd pick it up a notch. I'll try again this season.

By the way - I was just at the Toronto Boat Show, and with the exception of a couple of 50+ cruisers, not one of the boats I saw this year impressed me with the layout now that I am used to my 400 EC. I can really appreciate this fine boat now that I have had it for a season and compare it to million dollar yachts!