Twin 4.3 leaning due to same rotation props?

[Shubb]

I have a 1988 Sea Ray Sundance 27' with twin 4.3 V6 and Alpha 1 drives.
I just bought the boat, and it has been very well taken care of and mechanically perfect (so far, ha ha) But it leans after reaching planing speeds. It is also hard to track straight. I have gotten several different opinions as to why. Both drives rotate clockwise (from stern) and the boat leans to port.
I've tried the trim tabs and it only slows the boat down and causes more tracking problems. Transfering weight helps very little. The only thing I found was to trim 1 drive up slightly, this levels the boat out but does not help it to go straight.
Does anyone have experience with this? Would changing 1 drive to CR help? I talked to Sea Ray and the tech said look for hook or rocker in the hull. With a straight edge both sides look the same.
Any help would be appreceated.....Thank You

[yipster]

make sure you keep it perfect its a fine boat.
2 drives rotating clockwise should track pretty straight. it could be damaged or mismatched props
or drive allignment. did you check drives and tabs, oil reservoirs, lines etc? talk to the last owner?
her manual for a nautical laptop at: http://www.searay.com/owners_manuals...der2=88-89_270
also have a look at http://my.boatus.com/forum/ with more sea ray info.

[gonzo]

Drive alignment is pretty critical. They don't necessarily need to be parallel. Sometimes they track better with a bit of toe-in

[Shubb]

Drive alignment, you mean the actual outdrive itself? Or the trim tabs on the back of the drive?
If you mean the drive alignment that has to be corrected in the steering system right?
What is the best way to check for proper alignment and correct (or adjust toein) if necessary??
Thanks for your help

Pull the props off and take them to a GOOD prop shop. You may have 2 different props. Very possible, or 1 is worn down evenly with no vibration, or the most likely- same diameter, different pitch or different makes. If you speed up one engine or the other above MATCHED RPM does it straighten out better? Try it. Keep increasing or decreasing the RPM, IT HAS to balance. You can see if the rudders are both straight WHEN in gear? DO NOT get in the water and pull on them or look at them, with the engine running IN NEUTRAL!!! At any speed, you should be able to balance to straight ahead, by a very small change in 1 engine speed. If the rudders were locked in neutral. You sure would get the boat home--- to turn left or right by adjusting the 2 throttles ?

[woodboat]

When you accelerate in your rear wheel drive car the front does not lift evenly. It is more pronounced on a tractor-trailer. You have two engines biting and lifting in the same direction. It is bound to make the boat lean. This doesn't mean you can't get it straight but it will be more difficult.
http://www.mercstuff.com/changingtocounter.htm

[yipster]

great link woodboat, that cr conversion looks very good.
torque is by far not so pronounced as on a single setup, there are also 2 engines balancing eachother instead of 1.
i doubt very much if this leaning is to blaim on the dual drive's rotation, sounds more like something is stuck.
first simply check the trimtabs (and reservoirs for oil) you might hear the pumps but without oil they wont trim

[woodboat]

I have never been in a boat with twins that both went the same direction. With that said the old salts I grew up around always made a face and purposfully stayed away making nasty comments. Thinking out loud, if it weren't an issue why do most twins counter rotate? Why is a conversion kit offered if a single is more pronounced? Just some thoughts.

[yipster]

for some 13 years now we have the same boat had the same setup and sure i was looking for cr, its better in many way's. should have known your conversion before. blowing an engine in seaweed some years back made us go for efi with BIII's (but the extra weight shows)
how bout counter rotating engines (and no gearbox) for thoughts?

[gonzo]

On twin engines there should be no trim tabs on the cavitation plate. You adjust with the throttles. The toe in can be measured at the skegs to see if they are parallel or converge. Also, everything Richard said can be contributing. It may end up being a combination.

[Frosty]

The props might be different because of no CR. Some one might have not known this and switched them. Try switching them back

[GeoffSChapman]

I have produced several 7m boats with twin outboards from 90-100hp.
In these engine sizes you don't get the choice of cr and you just have to live with the boat heeling slightly. The first time you take someone out who has not experienced the heel, they dive across to the higher side.
You get used to it. The boat however tracks straight.
Geoff
Uniquest Marine

[Shubb]

After trying all the suggestions I got here (and many thanks to all) I still could not get the boat to drive level.

So I took my boat to a boat repair yard and lifted it off the trailer and put it on blocks. Once it was off the trailer I could inspect the hull and found a hook right where the boat sat on the trailer bunks. The bunks stopped about 4 inches before the transom and the weight sitting for so long caused a hook in the bottom right at the transom. The starboard side had 1/2" hook the port had 1/4". I had the bottom repaird flat, and identical on both sides and on the test drive it drove straight and level. What a difference!!
So I extended the bunks on the trailer about 6 inches to make sure it doesn't happen again. Thanks for all your help.

[BigD]

Shubb ....... Just found your old thread. What all was involved in fixing the bottom of your boat? I have the same problem with the hull of my 21' Reinell on the starboard side in the front half of the trailer bunk. It's about a 32" long indentation 1/8" to 3/16" deep in the middle area. It starts 26" from the stern.

After fixing the problem with your hull did your RPM and MPH increase?

Anyone else with any input please reply..... all info appreciated.

Thanks,

Don

[Shubb]

I had the boat lifted off the trailer and blocked up. Then made a template from the bottom at the transom. Then the bottom was prepped and filled with fiberglass/epoxy then sanded flat to match the template. I went back about 24" from the transom to make sure it was flat. I don't run the boat full throttle, I only cruise about 3300-3500 26-28 mph (remember the boat weighs about 9000# )I didn't notice a increase in speed or RPM, but now it rides flat and the trim tabs can be used to make adjustments in the ride.

I also had the trailer adjusted and extended the bunks to go 3"-4" past the back of the boat. So I'm sure the boat will sit completly on the trailer from now on.