Hey! Remember Clamps?

The tug PRESQUE ISLE has twin Diesel engines connected to chanagble pitch props through a gear box for a total of 14,840 BHP.  When mated with the barge PRESQUE ISLE their combined length is 1000'.

There are only a few of those, and they are "married" to specific barge units.  Which often have large overboard unloading booms, and significant bow thrusters.  All of which want connections bat to the towboat.

I want to remember the one in the photo is 2x 6000hp but I can't remember if that's deisel-electric, or direct drive.  I want to remember quoted top speed is 16kts with barge.

The lake bulk carriers seem to have settled on a 11' wide hatch dimension, and the width suitable for the specific ship's beam.  That hatch width accommodates the tipping ore chutes of the loading docks.

The cargo hols of the self-unloader ships have a central conveyor spanning the cargo holds to be passed to the unloading boom.

They use a rolling gantry to lift the hatches off as a single unit.  These are stacked on the adjacent  hatch in an alternating fashion.

Hmmm!CGBOb!

      Now that is an interesting looking Marine Critter. I have heard of them, But, this is the first time I've seen a modern one!  That would make a neat Model! What's the H.P. rating?

UhOh!ddp59!

 I misquoted,Sorry!

That's the Integrated Tug/Barge unit PRESQUE ISLE.  Here's s shot of the  tug.

If you look close, you'll notice that the center vessel is actually a pusher tug and barge.

Boatnerd.com is a site on Great Lakes shipping.  Lots of photos in their gallery.

I read somewhere that not only were there a serious 'bunch' of those clamps per hatch cover; they had to be set in a particular order to make a good seal, and you needed a six foot bar to set them.

Also, there are some videos 'out there' that show a laker out on big seas and you can watch as they sag and hog and twist. It's amazing that they don't all snap in two.

The designers of the lakers did not expect to be subject to shell fire, though.  Ships on Great Lakes were supposed to put into port to avoid storms. But of course time is money, so....

the U.S.S.Piedmont was not 794ft. long,L.O.A.

Length 530' 6" Beam 73' 4" Draft 24' 6" http://www.navsource.org/archives/09/03/0317.htm

the Booklet of General Plans USS Prairie AD-15 1968 states 529.5' oa