Yeah, it's not really a ferry. It's a barge that was used at the turn of the century or thereabouts to move stuff around the lake.

It's in around 75-80 feet of water not far from East Beach. Note that you're not allowed to enter the water from the swimming area, so head to the right (as you're facing the water), past the picnic tables, and down the trail a little ways, and you'll see a good entry point not far past where the trail heads into the trees along the shore.

Enter the water, drop down, and keep the contour on your right. You'll cross some kind of pipeline (small - water for a house?) and eventually come across the barge, which is pretty well preserved. It's a flat surface, and fairly shallow - five to six feet tall, if memory serves. It's been a few years. Cool old timbers making up the structure, but not all that big, and not a heck of a lot to see.

Lake Crescent can be a lot of fun - the Warren Car isn't divable any more without a permit, however. It's actually posted with a NPS sign on the side of the road, and I've almost always had rangers wander by when I'm out there.

The better diving that way is out at Salt Creek, a Clallam County park, with amazing salt water dives in the Strait of Juan de ***a. Do them, then rinse off on the way home in the gin clear bathtub of the lake.