25 cruiser fuel consumption?

Journey on;

The HONDA 90s are carb models so this is not an issue. If you check the MAVMAN sight you can get the service/operation manual as a pdf file. Sorry I don't know how to attach it from my site's C drive.

The FF transducers are nothing more than fuel flow transducers in the form of a little propeller in a tube that generates a 'calabrated' signal that corresponds with the quantity moving past it. Where the fuel goes, it does not care about the routing, only that the amount stay within its operating range for its size.

I spend a lot of time at speeds of abt 5kts and have watched the FF to be abt 0.6 GPH[total] and my dry tank's range of > 1000M with a full tank. THAT is a lot of ??? sitting! I think my tank has a stamp on it noting to be 107gals, though I set it as 100gal.. To truly get it right I have to go thru the calibration methods noted in the NAVMAN Manual...which I have not..only estimated it for my purposes from fill ups for confirmations.

I did it agn.. too much stuff.... The '3100 is a very worthwhile safety toy. I would do it again. Be sure to connect the NEMA data to the '3100 for more realistic range inputs/calculations from your GPS system..

For the NEMA standards you can check at -
http://www.kh-gps.de/nmea.faq

Sea Angel
 
The biggest MPG difference I see is is from the fuel load.

Full tank, (over 600 lbs.), heavy cruising weight yields low 2. something MPG.

Empty boat, low fuel and I'm over 3mpg.

The long term average is at 2.6
 
Cosmic C":17nymgao said:
Any ideas out there as to why my C seems to be such a gas hog? When we cruise we usually have a full water tank, rarely have much in the toilet holding tank, and carry two of us with reasonable gear. I usually trim to max RPM or MPH at a given throttle setting.

I'd appreciate any help.

Patrick
Click to expand...

Yessir...because you have a big, fat, heavy boat. :lol: Your mileage is right in line with what could be/should be expected for a 25' cruiser moving "at speed". It's actually quite good; you could have a deep-v 25-footer with a 225 or 250 on the tail end struggling to get 2 nmpg (and usually not making it).

The testing I've seen on this boat so far is totally bogus; either someone didn't read the gauges correctly or things got transposed back in the office because there's no way this side of hoping to get the rpm/speed/economy I've seen quoted.

Unitl there's a break-though hull design it takes a lot of horsepower to put a planing hull "on top"; the flatter (bottom) the better with respect to that but water is still a sticky unforgiving medium through which to push a hull. Speed on the water is difficult to obtain and it still takes raw horsepower to get the job done. The same basic engine as the BF135/150 in a Honda Accord will push it well (very well) over 100 mph...and still get decent fuel mileage!

I haven't seen a CD25 hit the water yet that's fully rigged and ready to cruise than isn't at or over the 5,000# mark (usually well over); if you want to plane that much wieght you're going to have to burn some fuel to produce the horsepower necessary to make that happen.

I'd say a realistic goal on the CD25 is 2.5 to 3.0 nmpg; the former fairly loaded and the latter pretty doggone light.

The only way to get outstanding mileage on the water is to slow down to hull speed or a smidge above; unless you have a very long boat that means some pretty slow speeds (like around 6 knots for the CD25). A lot of folks buy the CD25 instead of a "trawler" because it's capable of higher speeds and they want to use that capability...but it comes at a price.
 
Right on Les!

I have watched the '3100 read from a Range with a full go > 1000 miles to only 249 at WOT [5450rpm @ abt 23kts] for the weight Sea Angel carries, plus 3 adults.

All this is very much the ol' foot in the carb practice. How well do we plan our trip and how often do miss the WX signs and have to make that mad dash to the dock.

For all this, you still can't put a price on being out on the water in this loving, unforgiving, creation ... in your C-Dory. When a lot of the Parkers & Grady Whites are heading in or still at the dock because it is raining, etc., there goes the CD in her element.

I just love her and can't say enough good about the quality of the support and craftsmanship that goes with my Sea Angel.

Sea Angel
 
I appreciate all the responses, and it's nice to know that there are others out there who get the same mileage as I do. But I'm still disturbed that I (and they) are getting much worse mileage than other similar boats

We have to be careful in all these discussions, however, to keep our units straight. Some people and some reports are quoting nmpg, others mpg.

Les, I agree I have a big, fat, heavy boat (kinda like me, maybe), but I and others are still below your expected range by more than 10%. You quote a reasonable range would be 2.5 - 3.0 nmpg, which is 2.9-3.3 mpg, to be compared with my lifetime average of 2.6 mpg. Or, to put it another way, my lifetime average is 2.26 nmpg. I have never seen anywhere close to 3+ mpg (2.6+ nmpg) even when there was nothing on the boat but me and quarter of a tank of fuel (and I'm really not THAT fat and heavy!).
 
Well Meander with her 150 Yami has averaged 2.64 NM per US gal so far. By my calculations thats 2.93 MPG. This is over 951 NM traveled through the full range of speeds from slow troll to flat out. This averages out to 8.34 NM per hour for the 114 hours we have put on since July, so I guess "Meander" suits the way we boat. The fuel cost has averaged out to right about $10 Canadian per engine hour. It adds up but its still cheaper than a trip to Hawaii! :lol: The cost is what it is and it is still cheap enough to enjoy the boat without really sweating the fuel. At least until the fuel costs double.
Ron
 
Paul,
I don't want to say that you were misled, but there is a huge difference in light, empty, at the factory mpg numbers and real world numbers.

We started with a basic 25 and Honda 130. Then we added a dingy, radar arch, radar, all the other electronics, 2 hp Honda for the dingy, 15 hp Honda kicker, 5 gallons of gas for the kicker, camper canvas, extra foam pads and bedding in the v berth, lines, safety equipment, ditch bag with backup gps, binoculars, flares, 10 lbs of spare batteries, bear spray, whistles, etc. We also travel with charts, books, radio, tape player, spare parts (props, nuts & bolts, oil, Stabil), spare anchor, 4 fenders, 50 lbs of tools, cleaning equipment, fishing rods, two tackle boxes, nets, two downriggers, bottled water, gas barbecue, lanterns, backup starter battery, portable shower, cooking utensils, games, straps, foul weather gear, life preservers, oversized bilge pump, extra cushions, enough food for a month, two coolers, one for drinks and one for food. The water tank holds 20 gallons, the hot water tank holds seven, the waste tank holds 30 gallons, the fuel tank holds 107 gallons.

This doesn't include the "improvements" that we have planned for this winter and I'm sure that I'm missing a bunch of stuff, but I think that you get my point. We're not light travelers. We treat this boat as a home away from home and have loaded it with everything that we might need when we get on it.

I've discovered that weight really effects the performance and fuel economy. However, the silver lining is that the boat rides and handles a lot better with the extra weight.

The way we and some others load up these supposedly light and simple boats I'm not surprised that mileage is down to about 2.5 mpg.
Lyle (owner of big, fat, heavy Bess-C)
 
I don't have a Navman but I did spring for the Yamaha supposed equivalent. I find that it fluctuates a lot. I can be cruising along at a steady speed and the consumption can vary up to 2 gals per hour. It is only a very rough guide as to MPG. I guess it does average out over a longer trip so its still worthwhile. Does the Navman fluctuate like this?
Ron
 
Ron , when you say your your gauge fluctuates as much as 2 gals, is your gauge Yamaha . I have the 3'' dual fuel management . It is a Yamaha digital, and is right on , at all time. Only fluctuates very little if water is rough or I use the steering. Gary SEARAM
 
Gary,
Yes I have the Yamaha digital fuel management gauge. Its never stable rough, smooth or whatever its fluctuating steadily. I can be cruising along in flat calm water, holding a constant RPM and it will change up to 2 gals an hour. Are you saying yours just holds a consumption number when you maintain a constant speed? If so than my unit must be not working properly.
Ron
 
It normally takes me about a year to figure things out, but I think I have on my CD-25 with the Yamaha 150. Since some prop changes this spring, I have averaged right at 3.0 statute miles per gallon over 372 miles. One run (70 miles) was heavy averaging 2.91 mpg but was a fast run with very little slow cruising and some stinky seas for about 15 miles. One run of 202 miles was very heavy (3 people, two kayaks, a dinghy on the roof, 6 days of food, water, and drink, full water, and full fuel) but included 30 miles at hull speed. Average on that run was 3.01 mpg.

Here is the boat configuration:

Yamaha F150 with Permatrim
Solas Stainless 4 Blade Prop 15p
Holding Tank is empty and not used (Switched to Porta Potti)
Hot Water heater has been removed, but space filled.
Honda 20 HP kicker
Lenco Trim Tabs
Yamaha Fuel Flow (displayed on C-80 using NMEA 2000)

Prior to going to the stainless prop, I was using a Solas Aluminum 4 blade prop 15p. With that prop over 1700 miles we averaged 2.7 mpg last year. So we seem to have seen about 10-12% improvement in economy with the stainless prop. I also gained about 3 mph on the top end (35 mph at 5600 rpm) without porpoising. I alwasy trim for best fuel flow.
 
We don't have any meters but I keep track by calculating fuel used and miles covered over about 3000 nautical miles of use now. We have twin carburated Honda 90s with permatrims, trim tabs, and standard 3x13.5x15 aluminum props. We run on the heavy side and I trim the motors by feel and am happy with that after some practice and experimentation in the beginning. We get anywhere from:

2.2mpg towing the dinghy at high speed 18 knots in less than favorable currents.

all the way to.....

2.9mpg with some displacement time thrown in and lower 14-16 knot speeds.

I am sure we would see 3-3.5mpg with more slow cruising time.

I would say we see 2.3-2.5 as an average but we don't go slow very much.

I have been considering changing to some stainless props (not sure what size/pitch) but I have not seen enough evidence out there with twin users to think it will do anything but look better and maybe take a rock hit with less damage.
 
Stainless flexes less than aluminum or plastic, if hitting rocks is in your future it's better to do that with aluminum or plastic. Stainless being stronger is liable to cause more internal damage to shafts and gears in your lower unit. Folks who frequent sandy or muddy areas which can change after storms like stainless as they can chew thru sand and mud with out doing much damage to a stainless prop. Stainless as Tom said can offer high top speeds and better mileage because the stainless prop holds it's dimensions better under load.
D.D.
 
Agree with DD--a lot of the improvement is the SS prop and less flex. I run SS props on both of my boats in Florida--sand and mud is what we generally have--and if I hit an occasional buried piece of wood, it is with the engine trimmed up, and the nose cone will hit; not the prop.

On the boats we kept out West, we used mostly Aluminum props--fortunately we did not chew any of them up.
 
I am in the market for a couple of spare props so perhaps I should just buy a couple of stainless units and try them out keeping the alums as spares. Would I get the same size/pitch is the question I don't know the answer to.
 
My 26' ProAngler with a 200 hp Honda FI and 3 blade SS, 14 1/2" Solas prop..........

At 24 mph it is burning 8.3 gph. This is 2.9 mpg. That is the best mpg I can get at any speed or trim. Lightly loaded, 120 gals. of gas, no water, fishing gear and 4 people.

I do not have a Permatrim. Could it improve my mpg??? Best place to buy a Permatrim???

Thanks
 
Back
Top