BIG BANG coming from the out drive

+1 on Dennis’ “over the net” diagnosis. Shifting in and out of gear with out the engine running has likely caused your issue.

Bennett
 
Oh dear.... I just got a phone call from the mechanic who managed to see the drive from the swim platform (the boat is still in the water). He said that the gearbox broke in two pieces......

I will post some pictures tomorrow once the boat is lifted but this sounds like an expensive solution. We will see if there are signs of having hit something or if the destruction happened effectively by a spinning part that destroyed the housing.... we will see
 
Obviously I'm just taking a stab at this since it's hard to accurately diagnose things over the net, and regardless the drive needs to come off and the actual issue will be found. But, in the meantime...

-- If you hit something hard enough to damage a Bravo drive, you most likely would have felt the impact. And 100% guaranteed that there would be physical damage to the exterior casing. Since that would have been very noticeable and you didn't mention that...

-- When you did the shifting into and out of gear with the engine off, damage was done to the shifting mechanism in the drive. This is almost guaranteed to happen when a Bravo drive is shifted without the engine running. An Alpha can be shifted with no issues.

-- You left the marina and were still able to get into gear at this point. Running up on plane vibrated things a little more and the final damage was done. As long as you kept the throttle on, the drive stayed engaged in gear. Once you let off the throttle it allowed the drive to shift out of gear (since the shifting mechanism was now damaged to the point of failure).

-- At this point, the drive slipped out of gear at a high RPM and because of the pressure of the water on the prop started turning backwards. The gears then (because they weren't being controlled by a cable anymore) tried to shift into fwd or reverse at the same time the prop was spinning very fast.

-- Essentially, the drive tried to shift into gear with the prop spinning very fast. Like reving your engine up in neutral and quickly popping the tranny into gear.
I think I am with you Daze, I didn't feel hitting something; I think it was more of a mechanical issue rather than external objects. Pictures may confirm what you said; will see them tomorrow.
 
-- When you did the shifting into and out of gear with the engine off, damage was done to the shifting mechanism in the drive. This is almost guaranteed to happen when a Bravo drive is shifted without the engine running. An Alpha can be shifted with no issues.

I am curious, could you elaborate a little more?
What kind of damage can happen by shifting a Bravo drive with the engine off?
Is this all Bravo drives, B1, B2, and B3?

No sarcasm here, I just want to know for myself.
 
I am curious, could you elaborate a little more?
What kind of damage can happen by shifting a Bravo drive with the engine off?
Is this all Bravo drives, B1, B2, and B3?

No sarcasm here, I just want to know for myself.
Sometimes you have no choice but to shift when the engine is off, like stalled out in gear.
I've done it many times with no bad results. Having several Bravo's apart, I can say what looks like the weakest part is the shaft that has the jaws to accept the cable, the shift forks look plenty rugged.
 
Espos4 - it's all Bravo drives. Their shifting mechanism is the same.

Yes, it's where the shift cable attaches. When the engine is running, it allows for smooth/easy engagement of the clutch.

In the scenario of a stalled engine or accidental shift lever movement with the engine off... a safer way to get it out of gear is to slowly pull the shift lever towards neutral while at the same time trying to start the engine. As soon as the shift lever gets to the right spot to turn the engine over, the drive will easily come out of gear.
 
Sorry to hear this Jimmy.

Unfortunately, it might be recommended that the coupler be inspected or replaced as a precaution.

Best of luck getting her back underway.
 
Sometimes you have no choice but to shift when the engine is off, like stalled out in gear.
I've done it many times with no bad results. Having several Bravo's apart, I can say what looks like the weakest part is the shaft that has the jaws to accept the cable, the shift forks look plenty rugged.
The earlier drives came with an aluminum jaw that was prone to wear out and pop the cable coming out of forward. "bravo stuck in forward". Merc had a bulletin out in the late 90's replacing it with a steel linkage. Found that out the hard way. Mine was missed.
 
Ok, here's the outcome... Transom gone, gimbal housing gone, Bell housing gone....
Contrary to what pretty much everybody said, the forward / reverse gears seem to be OK ( I turned the propeller and I could feel / hear the pinions as normally you would feel). Also, assuming that I hit something has also been discarded since the the lower part of the drive itself is in good conditions and there is no sign of that. I couldn't speak to the mechanic to see what he thinks but in my opinion what happened was that the basket that holds the U-Joint gave in and as the engine was running at 3K+ RPM, the shaft got freed from one side and made impact with the neighbor components.

IMG_3061.jpg



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IMG_3066.jpg


IMG_3068.jpg
 
Wow, that's some carnage, for sure. Sorry to see that, Jimmy. That's definitely not an "normal" issue to have - a pretty rare sight. Lucky you, right? ;)
 
Very sorry to hear Jimmy :( - I think if they pulled my boat and I saw that I would just sit there and cry :mad:.
While it's quite unfortunate and probably an expensive repair remember that it's just mechanical and you can be happy that no one was injured because of it.

-Kevin
 
Wow! Sorry this happened Jimmy, after seeing the damage I don't think it is related to your shifting it while not running. You have a 22yr old boat (nothing at all wrong with that) and eventually even with good maintenance things wear out and something breaks. From the pictures, it looks like the U-Joint came apart first, and caused all the damage. The drive itself looks like it could be ok. The bell housing, gimbal ring and transom assembly obviously are not. I would also expect to replace the coupler while it is all apart.

Again, sorry, I've been there and know that sick feeling you get when something big breaks and you know it's not going to be a quick, cheap or easy fix.
 
Holy shit, was the boat taking on water? Like Bill said that looks like UJ destruction but it would have shredded the bellows. From your pictures it doesn't look like the the bellows are destroyed? Glad everyone is safe, hope you get it fixed quick and back floating soon.
 
The last picture show the u-joint bellows torn. You can see the coiled wire sticking out and a jagged edge of the bellows.
 
As I had a little more time to look through the pictures, I think your idea of either the center basket for the u-joint bearing or one of the yoke ends giving out makes sense. The question is "why". It could be simple fatigue from time/use, but it still could be something with the shift mechanism. The fact that you were just there and doing things with shifting while the engine was off is a big clue. Like I mentioned above, if it popped out of gear and then back in while the drive shaft is spinning fast, the basket/yoke ears could have been the weak link and snapped right off (think of the car/tranny example). Again, this is all conjecture - but the possibilities for multiple reasons are there.

Either way, the reason for it is, I'm sure, not your main concern at this point. Getting back on the water is! Knowing there was a HUGE shockload sent throughout the drive, it might be advisable to have it torn down completely and rebuilt or just replaced (possibly with the newer, stronger, X drive). You can double check me on this, but I think it can be rebuilt with at least some of the components of the X-drive.
 
Looks like lack of maintenance to me. You can see the wear on the u joint trunnion. Had the drive been removed periodically and everything inspected I think this could have been avoided. Looks like a very heavy boat for a single drive
 
Thanks to all for the words!! Very hard when things like this happen to oneself.

This happened in the least favorable moment... 10 people on board and being part of a cruise of more than 50 boats to The World Islands in Dubai.

A few replies:

- No, the boat didn't take any water. My first reaction after the boat stopped was to move the passengers away from the engine compartment so I could gain access to it; the bilge was dry. I phoned the trip coordinator and they send me a rescue boat; we eventually dropped anchor and enjoyed a nice BBQ and had a good time. The same rescue boat took us back to the marine (2 hour journey).

-Dennis, I will actually ask the mechanic to open the gearbox so we can inspect the pinions, engaging mechanism, actuator, etc for peace of mind.

-Kevin, it was funny seeing me and my wife walking behind the travellift taking the boat back to the shipyard; we looked like walking behind a dead body in a funeral!!!

Will see how much the repair will cost
 
-Kevin, it was funny seeing me and my wife walking behind the travellift taking the boat back to the shipyard; we looked like walking behind a dead body in a funeral!!!

That's funny (kind of) because I can picture it perfectly.

Good luck. The good news is that you'll probably end up with a far more reliable boat that you can be confident in.
 

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