Non step Top Gun re- power/rig splash
#1
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Well we finally splashed our 9900 lbs empty 97 Kevlar cover girl Top gun, with new 1.35 ratio Max machine Worx 2" shorter billet drives and 800hp motors.
We first tried a pair of 30 pitch labbed 4 blade Hydromotives swung off her stern.
Along with full fuel and four men, we blew right through them from a 2300 rpm slight grab to a quick 5 grand flash ,we couldn't get her on plane for the life of us.
We then borrowed a pair of new 32 pitch 4 blade Bravos and bingo out of the water she came at 3000 grand and several lbs of boost
.As we need to brake the drives in & seat the rings etc, we can't trim her out for at least 10 hrs, so far we have spent 5 hrs between 3 and 3500 rpms and up to 4000 rpms one time.
These props are still way to large for this application, but we do like the 55 mph cruise speed @ less than 3500rpms.
We also require way more tab than last year to keep her from porpoising and the drives also must be tucked completly in.
She always needed a ton of tab until the mid 60s and then she was a dream from there up to our previous 600SC powered 83 mph top speed drives out a few notchs 0 tabs.
Would turning our props in allow us to cruise with less tab dragging in the water? Or should we first try a 29 pitch 4 blade Bravo in a few more hrs, trim her up and then see if we hit our 5600 rev limit? She is real light in the nose and needs so damn much tab in the water could the right prop help this? any input would be much appreciated, thank's in advance!
We first tried a pair of 30 pitch labbed 4 blade Hydromotives swung off her stern.
Along with full fuel and four men, we blew right through them from a 2300 rpm slight grab to a quick 5 grand flash ,we couldn't get her on plane for the life of us.
We then borrowed a pair of new 32 pitch 4 blade Bravos and bingo out of the water she came at 3000 grand and several lbs of boost
.As we need to brake the drives in & seat the rings etc, we can't trim her out for at least 10 hrs, so far we have spent 5 hrs between 3 and 3500 rpms and up to 4000 rpms one time.
These props are still way to large for this application, but we do like the 55 mph cruise speed @ less than 3500rpms.
We also require way more tab than last year to keep her from porpoising and the drives also must be tucked completly in.
She always needed a ton of tab until the mid 60s and then she was a dream from there up to our previous 600SC powered 83 mph top speed drives out a few notchs 0 tabs.
Would turning our props in allow us to cruise with less tab dragging in the water? Or should we first try a 29 pitch 4 blade Bravo in a few more hrs, trim her up and then see if we hit our 5600 rev limit? She is real light in the nose and needs so damn much tab in the water could the right prop help this? any input would be much appreciated, thank's in advance!
#2
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The new drive is possibly causing some of the issues you are describing. It is very important at this point to break the motors in and then determine the pully and boost you want to run. At this point you can begin testing propeller that will allow you to record a WOT RPM and MPH via gps telling us how she is reacting to the new power and drives. From that point we can determine your slip and the performance allowing us to make a propeller recommendation for you. At that point we can also work on her attitude.
Julie
Julie
#3
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Wait to finish the break-in time frame. Definately try the 29 Bravo 1's. Figure on a 600 rpm increase over the 32's if they are Box Stock from Merc Racing.
Turning the props in will not help your tab issue. Once you can run the boat a little harder we discuss more prop options.
Turning the props in will not help your tab issue. Once you can run the boat a little harder we discuss more prop options.
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Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
Brett Anderson / BBLADES Professional Propellers
920-295-4435 http://www.bblades.com/
[email protected]
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