a pic for the nay sayers

[grouperjim]

put 200+ miles on the boat yesterday in the Gulf 1-2 close chop. weight equals 900 lbs fuel, 300 lbs fish/ice, 150 lbs gear, and two people.

prop is mirage plus 15 3/8 x 18 w/permatrim on a/v plate. engine is f250 w/300 hrs.....gets the hull on plane instantly, purrs like a turbine and gets awesome MPG. no bottom paint, engine mounted top hole, and no fuel additives other than ring free.......ethanol free gass (89). boat properly trimmed and tabbed.....burned 81 gals fuel.

 

[B-Faithful]

Here is a 25' May-Craft with 225 OptiMax (1.75:1 gear ratio) running 29.8mph (over bottom) at 4030 rpms buring 10.3gph with a 17" rev 4 prop on E10 87 octane gas and quickleen with half tank of fuel, regular fishing load, 2 people, bottom paint, and at almost slack tide on a glassy day.

 

[grouperjim]

is that 2.6 mpg?

2.6 mpg very heay load. after burning about 50 gals it was 35 mph, 2.7 mpg @4700 rpm. the increase was due to trading gas weight for fish weight which is carried further forward of CG, which consequently requires less tab.

the point is, the 18 mirage is a high thrust prop that delivers excellent mid-range fuel economy in big water. it is also a big prop diameter-wise and the f250 has the mid-range torque to swing it, and it will swing all the way to 5900 rpm. the boat is on plane at 17 mph (with a permatrim), and slow speed handling is also improved over a smaller 3 blade.

b-man: those will be some great numbers........for the new owner. what's the new Judge going to get numbers-wise with 300 zuke hanging on the back?

 

[DaleH]

2.6 mpg very heay load.

the point is, the 18 mirage is a high thrust prop that delivers excellent mid-range fuel economy in big water. it is also a big prop diameter-wise and the f250 has the mid-range torque to swing it, and it will swing all the way to 5900 rpm.

Wow - SWEET! No arguements with the way that info is presented! You might be convince me to put a light blue motor on the stern instead of the black motor I had been considering ...

 

[B-Faithful]

Judge with a 250 zuke yields about the same performance numbers my current boat does. 42mph at WOT and 27-29mph at 9-10gph. I am told that a Honda 225 burns around 8gph even at 25mph at its most efficient cruise.

 

[jcmcclellan]

Daleh, put a 300 Zuke on the back. You'll have a rocketship on the smooth water and the thing will probably plane at like 3000 rpms with the big blade the zuke swings and the M/V hull. Weighs about the same as a 250 Yami too.

 

[grouperjim]

not sure what you are saying. .........The're the same as yamaha perf bulletin for 23ccdv.

there is no yamaha performance bulletin for any 23 hull w/f250.

the point of the post is to give real world examples in the absence of such bulletins. at 5000 rpm i'm at 38/39 mph. the f225 doesn't have the mid-range torque to swing the 18 mirage.....i owned the 23dvcc w/f225. while he engines are similar in some respects, they are completely different in performance characteristics.

 

[DaleH]

Daleh, put a 300 Zuke on the back. You'll have a rocketship on the smooth water and the thing will probably plane at like 3000 rpms with the big blade the zuke swings and the M/V hull.

Yeah, but I didn't like the recent comparisons of the taller ratio gearcase on the 300hp Suzuki as compared to the 250hp. I don't care about WOT speed ...

I want CRUISE speed fuel efficiency ... as I'm a 'cheap' ******* ('til alimony is paid off anyway ).

 

[TheOtherLine]

prop is mirage plus 15 3/8 x 18 w/permatrim on a/v plate. engine is f250 w/300 hrs.....gets the hull on plane instantly, purrs like a turbine and gets awesome MPG. no bottom paint, engine mounted top hole, and no fuel additives other than ring free.......ethanol free gass (89). boat properly trimmed and tabbed.....burned 81 gals fuel.

Dang, I'm jealous. At 4800 rpm, with a full tank, I'm only doing 31-32 and maybe 2.2 - 2.3 mpg. Might have to make another call to Ken....
Try out mirage plus x 18

 

[TheOtherLine]

bulletin is for 225-4 yummiedog on dvcc yama 17 pitch SWS prop note wind was blowing 20-25 mph, t-top boat, 3 on board, full eisenglass, 3/4 fuel

Comparing Macintosh Apples to Granny Apples :roll:

 

[grouperjim]

actually, Opti provides an interesting point in his comparison of fuel economy between the f225 and f250.

point being that both motors yielded 2.7 mpg @35 mph heavily loaded. according to epa and independent dyno testing, the f250 has substantially more hp and torque. in this case, it was swinging a larger diameter prop with greater pitch, and pushing a slightly heavier boat, although the latter is debatable. and to achieve 2.7 @35 mph, the f250 was turning 300 fewer rpms. these findings provide a good example of the value and efficiency of mid-range torque.

don't get me wrong, i love the f225.......it's a smooth sweet sounding reliable motor........but based on my experiences, you really have to spin it up to at least 4500 rpms to get to the power band to realize any significant torque.

 

[grouperjim]

which is macintosh and which one granny?

doesn't matter.......they both have to be grannys, or both macs..........but please nothing associated with bill gates (he he).

opti: this is my thread, and is not a thread about the merits of the f225. it is a thread about the f250, its torque, and the props that work well with it. if a comparison to the f225 intrigues you, feel free to start a thread on that subject. i'll be sure to chime in to keep it interesting.

 

[grouperjim]

alright Opti, back on topic.

yes, that is what i'm saying exactly......my f250 which is a more powerful, and more thirsty engine is getting the same mpg at speed as the f208 which is obviously less thirsty and less hp. as a general rule, as you add hp to a given hull, you will suffer mpg penalty. in this case i increased hp, and mid range torque and did not incur a mpg hit due to being able swing a bigger more efficient prop.

B-man always wins....his boat is for sale....it has to be a winner......also not a DV hull. But seriously, i would like to hear what other f250 owners are getting mpg @35 while running heavy.....take a pic of your speedo/tach while running in a 1-2 ft sea/chop and lets see if there is a better more efficient cruising prop. so far i have not found one better than the 18. the 19 3 blade lugs the engine when running heavy.

FWIW my boat is propped for offshore fishing and cruise economy which is to say it may not be the right prop for you if that is not your thing. there may be other handling characteristics that are more important to you. if that be the case, then the rev4 17 may be a good choice for the 2320. BTW the rev4 17 is an excellent choice for the 2520 MV.

 

[gw204]

C'mon guys...you are just upset because you all burn more fuel than both of my boats combined....

 

[grouperjim]

that sure is a nice Grady hull you are selling Brian. good luck w/sale.

my wife got back from WI today and wanted to go out on the boat even though the wx was a little on the marginal side.

took some video which shows my hole shot with the mirage 18 and some cornering as we bustered 40mph back to the ramp. made it back just before all hell broke loose.

 

[gw204]

Thanks Jim. It was a tough decision to sell, but it's time for something different.

Your gettin' some real nice numbers with that rig. Good job setting her up.