Catching Air = Broken Drive
 

I haven't been able to have a real ocean boat yet so I haven't had to worry about this much in Havasu, but I always hear people talking about this. What is it that really happens That cause drives to break by catching air off of a swell? Is it people not pulling off the throttle and over reving it or is it when landing in the water it's much harder on the gears that causes them to break? For the purpose of this thread we will use a bravo x drive as an example with a 496 ho. Are the bigger drive's less prone to it (#6, NXT, B-Max) or are all drives equally as prone to it
Thanks,
James

They say the key to keeping your drive living a long life while "catching air" is to have your prop spinning the same rpms when its leaving the water as it renters the water.

Yep.:ernaehrung004:

The shock of loading and unloading the gears/shafts is deadly to them, as is over-revving and overheating the bearings, etc. It's kind of like dumping the clutch in your car ar 5500rpms. You can may away with it for a while, but it eventually catches up to you and you break parts.

Think about catching air this way:
The engine is turning 4500rpm (water conditions not allowing max speed)
The prop breaks loose and the engine turns up near max rpm (5400?)
When the prop reenters it tries to slow down the prop/gears/shafts/coupler/engine to the same 4500rpm. There is a lot of inertia to slow down and the torque is "extremely" high, much much higher than engine torque!
On a clutch drive like the Bravo, over throttling can be almost as bad as I described above. The clutch will decouple when the throttle is chopped too much and won't hook up again until the input/output on the clutch shafts are equal again. In a bad case assume the engine is chopped to almost idle, the prop reenters the water and speeds up, throttle is jammed full, engine free revs up on rpm until it "hits" the matching rpm!
Correct throttling saves equipment!

Not to mention the props. 4500 to 5400 back to 4500 and back again....kind of like a coat hanger. Only so many times you can bend the metal back and forth before it breaks...

So really it's the loading and unloading of torque on the gears and shafts? What can be done to the drive to help prevent that? Are the bigger drives less prone to this?

I would say just the #6?.

But they all can brake

The best cure for this activity is "Learn how to throttle".. and never miss!!

Shafts twist and break, cases flex, gears move out of alignment. It is pure physical abuse!! Proper setup can help, but having a #6 helps more.
I have several twisted and broken shafts and broken gears in the shop from customers drives..

Sometimes it takes a few broken drives to learn the skill and know your limits..
I personally am still searching for those limits, but my setup is much lighter and under powered compared to others.

Hope this helps.
D*ck