Counter rotating outboard jets?

[1pump]

My employer is looking at buying a used Almar to replace the Whalers we currently have to pull booms with. My boss isn't a boater, so he called me into his office yesterday to solicit my opinion on the matter.
He said it has twin Merc 135's with jet pumps, and the original prop lower units are included in the deal. I pointed out that jets might not be the best choice for the kind of work we do (he didn't know that jets don't have a nuetral gear like a prop and you need thrust to steer) so we might want to install the prop units.
A little later in the day I had a revelation- if the outboards aren't counter-rotating we can't use the prop lower units without severe handling problems. I'm assuming they are, but I've never heard of a reverse-rotation jet pump (although I suppose they exist). I'm supposed to take a look at the boat next week so I'd like to have my ducks in a row. It won't be worth as much to us if we can't switch to props.
Anybody heard of a similar situation? And how can I tell if one of the motors is reverse rotation (other than starting it and putting it in gear)? :whazzup:

[HntnFsh]

I could be wrong but cant see why there would be counter rotating pumps.The jet propulsion comes straight out the back.I wouldnt think you would have the problems you would encounter with props not counteracting each other.

[WaterDog]

I doubt one is a counter rotater. Since they are jets there is no torque steer. Does the boat have hydraulic steering? I'm thinking that if it does and it is rated for the combined horsepower you should not expeirence any torque steer at speed if you put the props on. How it will handle at low speed manuvering may be a different story. :shrug:

Fun to spend other people money. Make sure it's got fuel capacity for those unexplainable offshore jobs. (TUNA! ) :wink:

[AnglersRental]

The power heads in all outboards turn the same direction. The lower units are geared differently to make the motor "counter roatating", but it really isnt the motor that is counter rotating, just the lower units and props spin in opposite directions. To check the lower units, turn the shafts the same direction by hand. If they are counter rotating, the prop hubs should turn in opposite directions. Does that make sense?

If you think your boss might be interested in another used Almar, maybe show him the one I have for sale linked below. Thanks.

Brad

[WaterDog]

UG is right. Duh!

[1pump]

Oooooohhhhhhh.......OK. That makes a helluva lot more sense all of a sudden. :idea: I guess since inboard engines reverse rotate I was thinking along the same lines.

I saw the Uglygreen ad a few days ago and I planned on pointing it out to him since it's about the same size and in the same price range, and I'm not big on twins (twice the maintenance and weight). But this other boat is already set up to pull boom, and that's a major consideration. So we'll see what conspires.

[Keta]

HntnFsh,

The volute (pump body) is shaped to direct flow. I doubt if there is any manufacture that makes counter rotating pumps.

[HntnFsh]

Thats kinda what I was getting at.Maybe just didnt state it in a very clear way.

[Keta]

I have that problem too :whazzup:

[AnglersRental]

Piston aircraft engines, on the other hand, actually turn in opposite directions. This is because the propeller is actually bolted to the crankshaft and aircraft are very susceptable to gyroscopic precession.

Brad

[MacEFL]

I would have to guess that if you look at the props you should be able to tell if one is counter rotating. Otherwise you would be going in circles, he he.

[Keta]

UG,
One of the engines in the Tolley is a counter rotating Ford 351. We have to remember this when we replace the starter and distributer.

[1pump]

One of the engines in the Tolley is a counter rotating Ford 351. We have to remember this when we replace the starter and distributer.





Or the camshaft, and in some cases the crankshaft.
Older Ford cranks have a knurling pattern on the seal area that's cut to pull oil away from the rear seal as the crank rotates. The only difference between standard and reverse cranks is the direction of the knurling.
One of those weird little things you usually don't notice.