Pretty cool eh? Keep reading Ed! The MLWD (Mean Low Water Datum) on all the inland seas and rivers is 12 feet. Thats not to mean they cant be 1200 feet deep, but the guarantee is a 12 foot minimum. Empty ships on the lake draw up to 12 feet EMPTY, but the rivers are held in "pools" via the locks and dams. Full ships on the lakes need to pay particular attention to drafts when transiting harbors and channel marked reefs etc.
After building the subs, and some ships, the conning towers and pilot houses had to be added later due to "air clearances" on the bridges.
The subs draw about 20 feet and some ships also draw more than the 12 so they were delivered under power to Chicago, then "dismasted" and slipped into "drydock barges" and floated to New Orleans Naval Yard for delivery. Going east the St Lawrence seaway wasnt opened yet so the Erie Canal was used. The MLWD there is about 10 feet with air gaps on certain bridges at less than 20 feet... more planning ahead. Some of these numbers have changed in the last 75 years (!) but you get the idea.
So the old man was a test engineer for EMD and compiled performance data for the Navy on deliveries, my mom was the cook on board for the entire 2-3 week delivery run, AND her first husband (she was widowed in 1950) was the delivery captain. Thats where they all met up!
Subs, sub chasers, mine sweepers, and tugboats were barq' de guerre (sp) built on the lakes. The pics below are with mom and her first husband Art Z., Art Z. giving orders aboard a newly launched PC at far right (sub chaser) PC 538 and the PC 537 on sea trials on Lake Michigan.
Bill
https://researchandideas.com/index.php?title=America%27s_Fresh_Water_Submarines
