What's you MPG??

[fightinfire]

What model/size boat, engine size and make, and speed, MPG......

[peterb]

1972 23' SF w/twin 2000 200 HP Yamaha OX66's on a flotation bracket. Also 12 x 15 prop's.

Current WOT is around 54 miles per hour, and I get around 1.8 to 1.9 miles per gallon at cruise. I am hoping if I raise the engines (they are sitting too low) I get a better WOT and fuel consumption. Also, I could further improve the WOT if I went to a smaller prop.

[Old'sCool]

'73 23' w/bracket, 250 Yam. OX66 w/19 Yam. prop (motor probably too low)...last offshore trip was rough, 3'-4' w/APD of 5-6 seconds, 140 miles with 81 gal. burned.....1.7mpg...max. speed loaded is low 40's....6 dolphin, 2 wahoo...a good day in my book!!

[JohnB]

single 250 efi, best milage, 2.0 mpg, average for the day, is usually about 1.7-1.8. The weight, and top eat alot of gas.

[Briguy]

Peter B. You may be the armani of tshirts but you are the gomer pile of props. You definitely do not have 12"x15" props on your 23" Most likely you have 14x17'or 19's. I am sure because I had 13x19's when I had twin yami 130's.

To answer this thread I run 22" ss props on my twin 115 Suzuki 4 strokes and I get 28mph and 10.5gph at 4k rpm's for about 2.7mpg and that is with a full tank and 3 people. Max speed 38kts at 6300 rpm's. I may go to 24" props to drop the rpm's down to 5900 or so.

[peterb]

Oops. Typo. 15 x 21

[SECF3114M73J]

'73 23 ' center console, 225 h.p. Optimax. 15.5 X 17 Mirage Plus. I cruise at 4,000 r.p.m. at 26-27 kts. I average a bit over 3 m.p.g. Tops out 38-39 kts..

[WindTide]

20" Master Angler w/ 150hp Optimax 29.3kts @ 3900 burning 4.39 mpg. WOT 5100rpm @ 43kts. I have a T-Top and Coffin Box. I also installed a Stingray Fin recently to allevieate the tendency of this vintage to porpoise. I have tabs also, but I prefer to use them for ride if necessary, but not to the detriment of effeciency.

[Fr. Frank]

72 Seafari, 1991 Merc 150 reman'd 2002.

Cruise at 4300 rpm, 35 statute mph, 9.9 to 11.0 gph on the Navman 2100, or 3.2 - 3.5 mpg depending upon sea conditions.

Wide Open Throttle gets 6100 - 6150 rpms running empty, (depending on temp, humidity, chop, etc.) about 51-53 mph top speed, fuel burn about 18.8 - 19.4 gph, or 2.6 TO 2.7 mpg at WOT. No trim tabs, but these figures were with a nose cone on the lower unit, and engine mounted pretty high.

[Bushwacker]

1972 Seafari, 2007 150 E-TEC, Potter/Hermco Bracket; motor raised 2" from original setting (Cav. plate 2.5" above keel for 2.5' bracket setback + 2" = 4.5" above keel currently)
Boat has trim tabs, Doelfin on cav plate.

With Michigan Apollo 4B SS 14 1/8 x 20" pitch Prop:
Optimum Cruise: 2800 rpm/23 mph(GPS)/4.4 gph/5.2 mpg based on Floscan/BRP I-Command digital gage system
Max 5100 rpm/49.9 mph

With Michigan Vortex 4B Alum 14x20" Prop, same motor height:
Optimum Cruise: 3200 rpm/26.5mph/5.0 mpg
Max 5100 rpm/46.1 mph

The E-TEC's run a VERY lean stratafied charge system below 1000 rpm so mileage at ~ 5 mph trolling speed is 8-12mpg depending on current. Thought it would be interesting to look at total miles/fuel burn for both props to get a feel for true average mpg.

4B Alum. Prop: 175 miles/37.6 gal/4.7 mpg
4B SS Prop: 315.4 Mi/62.2 gal/5.1 mpg
Figured out that with gas @ $3/gal, I'll only have to burn another 480 gal to pay for the $360 stainless prop!