Any idea what would cause this?
I didn't hit anything.

Two things come to mind. The transom assy. has had a repair sometime in the past, if they cut corners and used parts that should have replaced.
Or I can't see the complete ujoint assy from the pics, if some part in the drive line let go you get major breakage.
Mac.

The u joint is trashed and broken.
I don't know if that is the cause or the effect.

The gimbal ring and bell housing are broken.

If it was my guess I would say that the drive shaft u-joint let loose and the rest is history. You have something spinning 3-4,000 rpm's and it breaks something has got to give --

I trust everyone was ok and besides this you made it back to shore in one piece.

3pointstar

I had it happen once before, and I too did not hit anything.
However, my U-joints and drive shaft looked fine.

Yours however, looks terrible. I suspect you had a lack of lubrication in there and/or water intrusion; which caused things to come apart. You will probably see some impact scars on the insides.

The inboard transom plate was replaced 3 years ago, so everything was apart and out of the hull at that time, maybe 40-50 hours of use since.

You would expect the ujoints would be looked at and lubed at the time.
Don't know how often you are supposed to pull the drive to check this stuff.

Yes, we made it home ok, drifted for awhile until help arrived, stupid anchor I have would not catch any traction at all.
Fortunately, we did not take on any water.

Time to start looking for some hard parts.

Take a peak inside your U-joints. Do you see any grease fittings?

Later model U-joints are sealed, no lubing. Earlier models DO need lubed probably once a year or so, not sure on the recommendation, but "BUP" will know.

It's not usual to see surface rust on those internal parts.

They break.. Period...

The input shaft must have stayed in the coupler/gimbal bearing? Lucky because a lot of water pours in through the gimbal bearing when it comes out.

I didn't think a broken u joint would break the gimbal ring like that, but there is a lot of power there.

Yes, I think I was lucky the shaft stayed in place and I didn't take on water.

I need to start finding parts,
Anyone know how to find my drive ratio, and whether I have a new or old style t-plate.

1995 Formula 271, 502, Bravo 3, 26p props.
Drive # is OF391190
Transom # is OF411486

There are no stickers on the drive.