Swapping Drives to Improve Porpoise
 

I installed new 350EFIs with new counterrotating Alpa drives in my '87 Stinger 260 a few years back. The reliability of this settup has been outstanding! Top speed is 59mph GPS with full fuel! Like most (all) other Stingers, the porpoise is still very much there if I try to bring out the drives more than a couple of bumps of trim. I read somewhere that owners of Baja's and other hulls with the porpoise tendency have been able to solve their problems back rigging the drives to turn the props in towards each other instead of the conventional outward rotation. Has anyone tried running the drives turning inward? Did it help the problem? How much of a hit did it have on top speed?

Re: Swapping Drives to Improve Porpoise
 

Good idea! I would be interested to see if that works. I have SBC with OMC Cobras that counter rotate outwards and I too have the same problem. Someone on here was saying though that it depends on where the reverse gearing is done. I'll wait and see what the experts say.

Re: Swapping Drives to Improve Porpoise
 

Exactly. Some boats (my guess is not high performance mostly) have reverse direction mills. Most have one drive that rotates in the opposite direction as the other. Lucky Volvo owners can switch the directions of the drives without taking them off and switch props.

I'm no expert. But the in vs. out rotation would effect the stern lift differently. I think that spinning in creates more lift. Somebody correct me if I am wrong.

Since the stern vs. bow balance relationship is the actual culprit in porpoising, theoretically it MUST change the balance relationship between the stern and the bow, and therefore MUST change the behavior of the hull when you trim out.

You have tried them spinning out. Maybe spinning in is the way to go.

Damn I wish I had new drives and power. :D

People who drive Stinger 260s are the coolest people in the world. Especially 1987. :D

I would love to hear about it if you try it.
Good luck.

Re: Swapping Drives to Improve Porpoise
 

actually its the "85" guys that are the coolest :drink:


and so far the fastest too :D


by the way Jon ya gonna be out this weekend. :cool:

Re: Swapping Drives to Improve Porpoise
 

oh . . .i may be the coolest an the fastest but im definetly not the brightest . . thats Packinair driving MY boat :eek: :rolleyes:.



not the one with her top off :rolleyes:

Re: Swapping Drives to Improve Porpoise
 

I have the telethon on Sunday.

I don't have my boat back.

But I thought about driving (yes, I know) the truck up to Clamdiggers to see who I could see.

Re: Swapping Drives to Improve Porpoise
 

I will give you fastest.

But coolest?
I don't know. You might not have enough purple on your boat.
:D

Re: Swapping Drives to Improve Porpoise
 

With alpha drives you'll have to switch drives,then you'll have to switch the way the cables to your shifters are mounted.you could just switch the drives,leave the cables as is but they will work backwards,forward will be reverse,etc.As for the cobra drives,I thought I read on this board that they are like bravo drives.That is that they are a cone clutch type drive and will hold up in either direction.In that case you would just have to switch props and change the shift cables at the helm.I'd check on that before trying though[legal disclaimer].By the way,does anyone know the weight of a 260 stinger with smallblocks and alpha's.I have an 87 I'm building motors for,hope to be in water soon.

Re: Swapping Drives to Improve Porpoise
 

cool . . .grab me a tote bag :D

Re: Swapping Drives to Improve Porpoise
 

magnum, i was wondering the weight of these things as well. i thought i heard #6500 but that seems kinda high, course this thing is a tank though :rolleyes: :D

what are you building for motors? any pics?