Twin 350 setup both units are standard rotation

[lenny2113]

I have seen many twin setups where one is a counter rotation. <br />I have a twin 350 on my Formula and both engines are standard rotation. <br />Is there a drawback to that?<br />Please, share your experience on this issue. <br />Thanks

 

[navigator336]

Re: Twin 350 setup both units are standard rotation

Almost assuredly, the counter rotation is done in one of your transmissions. This is better than counter rotation engines as the engines are designed to rotate in one direction. The marine builders adapt them to counter rotate which can cause some power loss.

 

[lenny2113]

Re: Twin 350 setup both units are standard rotation

Navigator, <br />That is what I thought until I pulled the boat out of the water and noticed that the prop pitch is the same on both outdrives. <br />My question stands: What's the drawback of same rotation?<br /><br />Thank you.

 

[CCrew]

Re: Twin 350 setup both units are standard rotation

The drawback of same rotation on both--if the motor and outdrives are identical.. Is that the boat can and usually will torque steer. With both turning in the same direction you're forced to compensate for a sideways move in the stern opposide the direction of rotation. <br /><br />Many manufacturers found it was easier to counter-rotate the I/O unit, as it was a gear change, rather than the crank and cam changes necessary to counter rotate the engine itself. Also allowed them to ues only 1 engine package rather than 2. <br /><br />-Roger

 

[rodbolt]

Re: Twin 350 setup both units are standard rotation

hello<br /> duuude your going to go in circles.<br /> hahahaha nahh just kiiding.<br /> the sterring torque is a minor issue if you have power or hydraulic steering.in fact you will never notice it unless it fails. the paddle wheel effect of the propellers rotating in the water may have a very slight tendancy to move the stern of the boat in the direction of prop rotation. this will be most noticable at medium speeds in quarting/following seas. A friend of mine converted his single to twins and both standard rotaion. at 65 MPH we did not notice any difference. some times I think counter rotation is to much hype. if you boat runs well and tracks nice dont sweat it.<br /> good luck and keep posting

 

[airman]

Re: Twin 350 setup both units are standard rotation

You'll see the most handling issues at docking speeds, especially in reverse. My twin engined Trojan (counter rotating inboards) backs dead straight. My uncle's boat (single I/O) has so much propwalk in reverse that it simply can't back to starboard. The propwalk can be an advantage or a disadvantage, depending on if you are aware of it, plan for it and use it.

 

[jnova1111]

Re: Twin 350 setup both units are standard rotation

if you have dual porps on each drive then it doesn't matter.

 

[lenny2113]

Re: Twin 350 setup both units are standard rotation

Thanks to all for your posts.<br />rodbolt, I like your post: "duuude your going to go in circles" - made me laugh <br /> <br />She has hydraulic steering and I thought it was a counter rotation at first because I did not notice a stern pull to starboard while testing the boat before I bought it. <br /><br />Thanks to all for support,<br />Lenny