How could they build submarines in Manitowoc on Lake Michigan?

The family-owned Manitowoc Shipbuilding Company. was an experienced shipyard. They had built many ships, such as ore carriers, that operated on the Great Lakes. When the war broke out, they wanted to assist in the war effort and keep their staff employed. Although they had no experience building submarines, and originally turned down the project, they worked with Electric Boat in New London to prepare. They then built 28 submarines as a subsidiary of Electric Boat. The sailors in Manitowoc boats really appreciated the high quality of the work.

Manitowoc Shipbuilding faced multiple challenges:

1. In order to understand how each piping or wiring system fit with the whole and the order of installation for each one, the shipyard first built a full-sized model of a submarine out of wood.
2. They were building ocean-going submarines in a freshwater environment. Fresh water is less dense than sea water meaning that it doesn’t support as much weight. That, in effect, makes the completed submarine act as if it were tons heavier. They had to compensate for that so the boat wouldn’t go straight to the bottom when it submerged the first time.
3. Manitowoc submarines had to be launched sideways at commissioning due to the location on a river. That had never been done with these boats. There was concern that the sudden roll would damage some of the battery cells or that the boat would roll over. The engineers decided to launch without the battery cells installed and calculated the expected roll of the boat. The calculations were exactly correct and everything worked out well.
4. Winter conditions on the Great Lakes are harsher than in Portsmouth, New London or Mare Island. The submarines undergoing sea trials in winter collected quite a bit of ice when on the surface. Much of that had to be removed before diving because of the added weight. It made the boat top heavy and less stable. This was also an issue, although to a lesser extent, in Portsmouth and New London.
5. The boats then had to be sailed or transported to salt water.

In spite of all the things the Manitowoc shipyard had to do just to be able to build these boats, they completed nearly all of them ahead of plan and under budget. All but one of the boats were completed ahead of schedule, entitling the shipyard to performance bonuses. They accepted some of the bonuses but not all, since they thought it improper to make too much profit during the war.

The shipyard was also building landing craft and heavy cranes at the same time. That construction did not interfere with building submarines or vice versa.

Today, getting boats from Manitowoc to the ocean would be straightforward. You would just sail the boats to the Atlantic Ocean using the St. Lawrence Seaway. However, that wasn’t completed until 1959. In 1941, the locks in the Erie Canal could not accommodate a ship longer than 300 feet and the locks on the St. Lawrence River were even shorter. These submarines were nearly 312 feetlong. Therefore, the only water route available was through the Chicago Sanitary Canal to the Illinois River and then the Mississippi down to the Gulf of Mexico. (Yes, the Chicago sewage canal.) The submarines would be towed through Chicago to Lockport, IL, loaded onto a floating drydock (somewhat similar to a barge) and towed (pushed) down the rivers. The Manitowoc shipyard needed to buy or build the drydocks.

Chicago had built drawbridges which would have allowed the drydock to navigate the Sanitary Canal had they all been finished. The bridges were all functional for road traffic, but some of them didn’t open. The shipyard needed to complete the rest of the mechanisms to raise the bridges.

The completed submarines, even on the floating drydocks still would not fit under all the bridges on the Mississippi. To solve that, the periscope shears, periscopes and radar masts were removed before entering the Chicago Sanitary Canal and were reinstalled in New Orleans.

One interesting story concerns a delay due to high water in spring on the Mississippi. They had to wait several days for lower levels of water in the river in order to get under bridges. There was no alternative other than to tie the tug and floating drydock up to trees and wait. At times, submarine builders needed to be as resourceful as submariners.