Breaking up ice around boats

Photo: Creative Commons, 2.0.

The bitterly cold January of 1805 trapped the Corps’ keelboat and pirogues in ice. Some sections of the Missouri were eight inches thick; others were over three feet thick.

The men quickly realized that chopping or cutting the ice was fruitless. So two slightly different techniques were tried -- both required heating large stones in a fire. The first idea had the men placing the hot stones directly on the ice adjacent to the sides of the boats, hoping to melt the ice.

The other approach was to place the hot stones into some water in the bottoms of the boats. In theory, the hot water would warm the edges of the boat and melt the ice so as to free the vessels.

In reality, both ideas failed because the stones couldn’t take the heat of the fire and burst. Several types of rock were tried, but with the same disappointing results.