Counter rotating engines

[DropTop5.0]

What's the purpose of counter rotating engines? Does it have to deal with steering? What does one do if they have trips?

 

[Gimme Fuel]

Engines counter-rotate to offset the sideways thrust component of a spinning propeller. A standard RH rotation prop throws a wash from the top of the prop in the direction of rotation.....in this case to the right. It also throws a thrust component downward creating stern lift. With triples, usually the center and starboard engine will be RH rotation and the port will be LH rotation. The rotation of the propeller is very important to handling characteristics. If both propellers turn outward on a twin setup, the stern is settled and rides in the water fully. If you spin the props inward, it will lift the stern harder and usually result in higher top end speeds but most of the time handling is diminished and the boat can act squirrely with the stern running that loose. Most newer stepped hulls built for extreme top end speeds will turn the props inward. It is easy to test the effects out on a Bravo drive boat with twins. Simply swap props and run in reverse. Bravo's have straight cut gears so running in reverse will not damage them. If you like the results, just change the cables in your shifter to right the shift lever directions. There is no difference in a bravo counter-rotating drive from a standard....one just runs in reverse. It is actually recommended by quite a few drive guys that every year the drives get swapped side to side for even gear wear. Others oppose it because they believe doing this loads the gears in a different direction and causes premature failure. In the end, bravo drives running fast will break, just a crapshoot as to when. Running synthetic gear oils with shock additives has greatly increased the life between rebuilds. Also, a system can be home built to circulate, cool, and filter the gear oil in the upper. Even with drive showers, oil temps can reach 300* very quickly with modified engines.

 

[RNGRDVE]

Excellent Fact Check.

 

[Gimme Fuel]

Excellent Fact Check.

I read OSO like its my job.......I may have learned something without the use of the dreaded Google machine....

 

[DropTop5.0]

Wow, thanks Ron. I'm a lot smarter but I still need to digest everything you said.

 

[Gimme Fuel]

Sorry, I know that is a lot.....I have a hard time stopping when I get on a roll....

Especially when is involved....

 

[sim]

Now THAT was freaking impressive. That's why I keep coming around here. For an edumacation.
No, seriously, that was really cool. Thanks!