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25 June 2007 @ 04:06 pm
fixing cars and testing boats  
I bought a used transmission for my Geo Metro down in Middletown. As of last night (Sunday), the old one is removed and the new one ready to go in after the new clutch out at the garage in Camden.

It was nice having some rain this weekend because all the plants really need it even though it dampened the other thing I did this weekend -boat testing.

Friday and Saturday nights I did trips with a stopwatch back and forth the 1-7/8th miles between the West Carrollton boat ramp and the Moraine boat ramp. I also carefully measured the fuel consumed.

Here are the results:

total weight -245 pounds

Friday night - maximum smooth planing speed: 6.01 mph
fuel consumption: 22.3 mpg
(34.45 ounces per hour)

Saturday night - minimum reasonable displacement speed: 2.57 mph
fuel consumption: 44.9 mpg
(7.34 ounces per hour)

The slow trial would be much more fuel efficient probably in my little pontoon kick boat (less viscous drag) but it was still good. (This little Honda motor holds the world's record for boat fuel efficiency -about 125 miles per gallon, so I know I can do better than the 45 mpg I got.)

The problem with my planing was that I was only going 6 mph. I did the Savitsky calculation on this and determined that my effective horsepower was only .322 HP. I should be able to get at least twice this from this motor, and get near or above 10 mph and maybe with better fuel mileage.

The problem is very obviously with the propeller pitch. This motor is designed to be like a trolling motor so the prop is like first or second gear in a car or like a farm tractor vs. a car.

Since I am using the motor to push something fast that's very light instead of slowly pushing a heavier boat, I nead a "high gear" prop. I'll be learning this week what other little props will fit the little motor and maybe I can find a higher speed one to try out.

Below is a picture of the rig at the West Carrollton ramp, and 3 more pictures are here: North Pak Aquarius with motor .



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I also started learning to use this weekend another neat thing for a low-energy life -candles. You can buy many different kinds and they are fun as well as practical.

Finally, this coming weekend is forecast to be nice. I am expecting Dad and Sue to visit so I am putting this link here in case they read this journal entry and want to walk across the bridge to the CityFolk Festival when they are here: 2007 Dayton CityFolk Festival.