 It would also carry the engine, boiler and wood to assemble the side-wheel paddle steamer tug, "Uncle Sam" to the Colorado River Delta.The "Uncle Sam" would be the first of many steamboats on the Colorado River.After arriving in early September, the "Capacity" then had to wait longer than expected, over two months, in the anchorage in the estuary of the river until the "Uncle Sam" was built and launched in mid-November and then again waited four more months to empty its hold of the Army supplies.