Postcard from Divers at Work Through the Ice in Duluth

"Hard hat diving" was a thing that was fairly common to help salvage equipment, fix pipes or build breakwaters. Here's a Lake Superior Magazine article about someone doing the work: "Lake Superior Journal: Paul Flynn, Hard Hat Diver"

Above: Back in the 1870s.

And a current family with history ...
Duluth News Tribune: "Lakewood Township family with longtime diving business delves deep into history"

That was back when folks wore their long johns year round and washed them once a year whether they needed to or not. Look at all the different hat styles. Notice not one man without a hat? Yet not one baseball cap? Diver is wearing a Greek Fisherman's cap under his helmet. Tall guy who could tear you limb from limb is wearing a hat that doesn't know what it wants to be but it's all good because he's wearing a hat. The young men are wearing hats they can grow into as adults. The ladies wore hats with exotic dead bird parts from South America.The age of the beaver hat has ended by the time this picture was taken. All of these men would shit their pants if they saw a black person, or a young lady in a bikini.

The gent featured in the photo posted by Gina may well be Major John Upham, who was behind the wheel of the dredging tug Ishpeming when the vessel cut the Duluth Ship Canal in 1870 and 1871. Upham was also called “the submarine diver of Duluth,” as in 1871 he surveyed portions of the St. Louis River by donning diving gear and walking along the river bottom. Photo shows people outside of LS&M Railroad's freight depot just west of grain elevator A at the foot of 4th Ave. West. The postcard was printed between 1900 and 1915 but the photo could have been made prior to that.