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With the new SmartCraft tach installed (and my handheld GPS), I performed a full test on the boat this morning with my daughter's help. I made a chart before we went out. She wrote down the numbers as I read them off the gauge. As you can see, we didn't do the WOT test today. A surprise storm was coming and we had to get back to shore. I'll post WOT data once I have it. I'll also re-record the data at all speeds when I'm in the boat by myself at a later date. Should help efficiency somewhat compared to a family of 4 on board.

RPM - gph - Speed - MPG - Prop Efficiency
790 - 0.1 - 2.8 - 28.0 - 53.5%
1000 -0.2 - 3.5 - 17.5 - 52.8%
1500 -0.3 - 4.9 - 16.3 - 49.3%
2000 -0.5 - 6.1 - 12.2 - 46.0%
2500 -0.9 - 6.7 - 7.4 - 40.4%
3000 -1.4 - 7.7 - 5.5 - 38.7%
3500 -1.6 - 15.3 - 9.6 - 65.9%
4000 -1.9 - 21.1 - 11.1 - 79.6%
4500 -2.4 - 25.1 - 10.5 - 84.1%
5000 -3.0 - 28.7 - 9.6 - 86.6%
5500 -3.3 - 32.7 - 9.9 - 89.7%
6000 -TBD - TBD - TBD - TBD


Notes
4 gallons fuel
4 persons (2 adults; 2 children - approx 360 lbs.)
Moderate gear
Bimini top up

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There. That should be easier to read.

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I ran another test today with just me in the boat and the bimini top down. The figures below are based on a two-way average.

RPM - gph - Speed - MPG - Prop Efficiency

4045 - 1.7 - 22.7 - 13.8 - 84.7%
5520 - 3.2 - 33.8 - 10.7 - 92.2%
6155 - 4.0 - 38.9 - 9.7 - 95.2% (WOT)

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Your boat almost gets better gas mileage than my truck!

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Yeah, mine too. Isn't that hilarious? My SUV gets 13 - 14 mpg on a daily basis.

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I have the same setup 2007 version. What prop are you using? I don't get anywhere near your performance with the oem prop. Did anyone consider some type of dolefin set up? Mine runs pretty bow high.
Thanks for your response

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Mine has the 14P OEM prop. My motor is rasied up one hole from the stock location (which is the center hole). That might make 1-2 mph difference on the top end. I also weigh 140 lbs.

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Your running over 6100 at 90% throttle:o. Seems about 600rpms high, I would think. What pitch prop are you using?

rich

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I'm not sure how you get 90% throttle (I was at 100%) or 600 rpm high (the top of the WOT range for this motor is 6000 rpm). I'm running the stock 14P prop. This was a very light load with only me in the boat.

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That is one fast 13 ft. Whaler, almost 39mph. My daughters `76 classic 13 will only turn about 34-35 mph with an `03 2 stroke Merc. Mercury Marine/Boston Whaler test results with an 08 13 ft. Whaler and an 08 25hp 4-stroke is 25 mph.

http://www.mercurymarine.com/look_dee...oke2530=10

Note that the newer 13 footers weigh in at 600lbs. while the Classics are almost half that weight.(the tests show dry weight does not say if it include driver) Does the newer 13 footer still have a hooked bottom?

rich

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Here is the test results conducted by Boston Whaler/Mercury Marine using an `08 13 foot Whaler and an `08 40hp 4 stroke Merc. Their boat and motor combo tested 5 miles slower than your tests at WOT. What do you attribute your higher top end and through the rpm speed to. It seems that the props are the same pitch.

http://www.mercurymarine.com/look_dee...oke4060=11

rich

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It's hard to say since the test omitted all of the conditions present at the time of the test (e.g. temp, altitude, weight on board, etc.). In addition, the prop efficiency in that test dropped from 89.4% at 5500 to 87.7% at 6000 instead of increasing as it should. Most likely, the driver overtrimmed the motor at WOT causing some loss of speed. Add to that the fact that my motor has been moved up one mounting hole and the driver probably outweighs me by 50 lbs. All of these factors probably cause the difference.

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Binkie - Congrats on your 1000 post. You are in a league of your own when it comes to wealth of knowledge. There are a few close on your heals which just blows my mind as 6 months ago no one was even close to this mark (excluding the admins). Glad to have you around. :D

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Binkie would have made Admiral had WC not done away with the ranking system!

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I managed a one-way run of 39.5mph. 38.9 was the two-way average. I suspect I could easily crack 40mph with a SS 15P prop. But I'll never use a 15. The holeshot would be dreadful.

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Thanks Rob and Cliff for the compliments, just having fun, and learning a lot about Whalers. Don`t think being an Admiral would suit me. After 6 years of Coast Guard Reserves back in the sixties, I was still a Fireman when I was discharged. Of course we were just putting in the time, back then. Not much motivation. I don`t even remember anyone ever making 3rd Class Petty Officer in the Reserves.

As far as those tests made by Whaler and Mercury, with the 13 footer, I think the tests are flawed somewhat, somehow. The test for the 25 merc 4 stroke shows 25mph with a 9 inch pitch prop at 6000rpm. So when I bought my new Merc 25 I got an 11inch prop, and got 29 mph
at 5100 rpm WOT. Lousy hole shot though, but it will plane two women and myself at 26mph with the engine jacked up to where the plate was about an inch above the water. Lot of ventilation though. I have since lowered it an inch, but have yet to test it.

rich

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The best part of these 13's . . . I spent the morning with my 7-yr old daughter on a local chain of lakes yesterday. We ran around 3 of the lakes, went swimming, had lunch, etc. We burned a total of 0.7 gallons of fuel according to the SmartCraft gauge. Gotta love it !!