• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

Direct Drive verses Gear Reduction or Belt

Southern Airboat Gallery Archives

p2's work counter
537988_340402299342976_100001196256227_871131_1352598713_n
Best Looking Airboater in the marsh
little ivan
Grasshopper Brochure Page 5
When the hell are they going to finish????
G

GWTW-000

Guest
Can someone give me some pointers on the differences I could expect concerning Direct Drive verses Gear Reduction Units and Belt Drives? I have bought a used boat with a 502 Caddy on a 12’ 6� fiberglass Kennedy hull. It has a wooden prop 70X? running as a Direct Drive. Should this boat run dry and if not would changing to GRU or Belt Drive help? Also how much horsepower would a stock 502 produce?

Thanks
 
It should run dry on that small of a boat but reduction units will always run dry better than direct drive. The prop is probably a 70 x 40 or more if it is a paddle prop. I'm in the process of converting from a sbc to a 500 caddy now and I'll be running a 72/38 paddle prop. As far as horsepower it depends on the year of the engine. here is a link for some caddy info. http://www.geocities.com/MotorCity/Pit/ ... ineid.html. The torque of the caddy is the big +. Thy have a lot of torque and peak is reached at around 3000 rpm. They are also only around 60# heavier than a 350 chevy. Here is another website with caddy info.
http://www.cad500parts.com/faq.htm

try it out and let us know how the boat performs the way that it is.
 
I forgot to mention that if you decide to go to reduction that you will have to have the engine modified as it was not designed to turn the high rpms that the reduction will produce.
 
It will make a huge differance from what I have seen going to a reduction drive,afriend of mine just went from straight drive to a belt drive and it was a night and day differance in the power and performance
 
It will make a huge differance from what I have seen going to a reduction drive,afriend of mine just went from straight drive to a belt drive and it was a night and day differance in the power and performance.
 
I went from a driect drive to a rotator and there is three times the torque and a lot more power boat runs dry very well and jumps right on a plane fully loaded.
 
I had to slide mine about 10" foward because of the turbo prop if not probley 7" would haved worked
 
You must log in or register to reply here.
Back
Top