posted 03-28-2001 08:51 PM ET (US)
Today was a very cool day and the water was running pretty good on Lake Austin after the 3" rain we had yesterday. Lake Austin is the Colorado river that runs between Lake Travis and Town Lake.I wanted to be sure I got all of the variables for Clark's formula. I went to the Central Transportation Systems certified scales today to weigh the rig so we could get the actual weight less the driver.
I did not have time to unload the boat and get the trailer weight. I will try to do that this weekend. The boat with the trailer weighs in at 1300 lbs. That is full of gas and the exact way I ran it last time. Plus I had alot more clothing on tonight.
The only missing variable now is the trailer weight that needs to be subtracted from the 1300 lbs.
Also my weight is about 205 lbs. Depending on how much mexican food I had at lunch.
Tonights results are as follows:
Boat ran great and gave me the exact same readings at 5900rpm's, I achieved 45 mph per the Lowrance X65 paddle well speedometer.
The new Gps I bought is the Garmin 3 Plus. I could not wait for the new series Garmin's to become available. This will be my back up unit. Very easy to use and matches my truck speedometer. Plus I got an additional 10% off because I opened a charge card with West Marine.
Readings between the gps and X65 are not consistent unless I go perpendicular to the current. Lake Austin is way to narrow for a good test.
The readings with the gps falls in line with Clark's formula I think. The gps top end speed at 5900rpms indicated between 34.6 and 35 mph.
Conclusion: The stock prop of 15" is diffently not a good match with or without gps readings. The hole shot was terrible and my X65 speedometer would not read above 37mph. After the new prop 45mph.
Do not buy the X65 speedometer option because based on the gps it is worthless.
I have not tested the odometer function for accruacy. So my mpg is now in question also.
Question: What was the original performance of the stock prop based with the gps readings? I will retest with old prop.
Clark please run the numbers for us on the new known factors.
Additional question: What do I do now? I am happy with the performance.