I Googled what it said on the building, Redondo Marina. Today, it looks like a pretty high class place near LA. So, my guess is that something went wrong in a publicity demonstration. Now, if those had been OMC RDs,or Big Twins, the motor brackets would have snapped off, but not the whole transom….Those damn Mercs….(-:
I have seen it before as well; it shows up on the racing forums now and then. There is a story behind it that I remember only vaguely. As others have said….it was a mishap that happened to get caught on film. Carl was said to have threatened the photographer “big time” not to release the photo. I think it was not until the photographer’s death that the image was finally put out there.