The Colorado I (also known simply as the Colorado) was a stern-wheel paddle steamer—the third steamboat overall on the Colorado River and the first sternwheeler to operate there. It played a key early role in commercial navigation on the lower Colorado, helping supply military posts, support settlement and mining, and prove the viability of sternwheelers for the river’s shallow, shifting, sandbar-choked waters.
Construction and Launch
George A. Johnson & Company (the dominant early operator on the river) commissioned the vessel. It was built in San Francisco by the noted California steamboat builder John G. North, then disassembled, shipped by sea in sections to the Colorado River estuary (in Mexican territory at the river’s mouth on the Gulf of California), reassembled, and launched in December 1855.
Captain Isaac Polhamus Jr. (who would become one of the most experienced pilots on the river and later command several other vessels in the fleet) took command.
Specifications
- Type: Stern-wheel paddle steamer (wooden hull).
- Length: Approximately 120 feet.
- Engine: 80-horsepower steam engine.
- Cargo capacity: Up to about 60–70 tons of freight (sources vary slightly; some list ~60 tons, others up to 70).
- Draft: Less than 2 feet when loaded (ideal for the Colorado’s shallow conditions and frequent sandbars).
- Other details such as exact beam are sparsely recorded in surviving accounts, but as a sternwheeler it was narrower and better suited than sidewheelers for navigating the river’s narrower channels and sloughs.
Compared with Johnson’s earlier sidewheeler General Jesup (launched 1854, ~104 feet, 50 hp, ~50-ton capacity), the Colorado I was more powerful, carried larger loads, and handled the strong currents and obstacles more effectively. Sternwheel design also allowed techniques such as reversing the wheel to help free the hull from sandbars.
Role on the Colorado River
Steamboats on the lower Colorado (from the Gulf of California upstream toward the Virgin River area) began in 1852 primarily to supply the isolated U.S. Army post at Fort Yuma more cheaply than overland freight. Early sidewheelers like the Uncle Sam (1852) and General Jesup proved the concept, but shifting sandbars, low water, strong currents, and tidal bores in the delta made the work difficult and hazardous.
The Colorado I improved efficiency on the core run between the estuary (where ocean vessels transferred cargo, often midstream to avoid Mexican customs) and Fort Yuma. It made faster upstream trips with larger cargoes. It also towed barges at times, further increasing payload.
Beyond routine freight (supplies, goods for settlers and mines), it supported military operations. During the 1858–59 Mohave War and the establishment of Fort Mohave, the Colorado I and General Jesup carried troops and supplies upriver under contract (reportedly at $500 per day). It contributed to the broader expansion of river commerce that later served mining booms (including areas like Eldorado Canyon) and settlement in what became Arizona, California, Nevada, and adjacent Mexican territory.
Johnson’s company held a near-monopoly for years; the Colorado I was an important part of the early fleet that generated substantial profits before competition and, later, railroads arrived. Navigation remained adventurous—pilots frequently dealt with grounding, low water, and the need for wood fuel from riverside yards often staffed by local Indigenous people (including Cocopah).
Ultimate Fate
After roughly six years of hard service (frequent groundings, wear from sandbars, and the river’s harsh conditions), the hull of the Colorado I was worn out. It was dismantled in spring 1862 (sources commonly cite April 1862; some secondary accounts mention August) at or near Fort Yuma / Arizona City.
Its engine and boiler were salvaged and installed in the larger successor vessel Colorado II (launched 1862 at Arizona City under the protection of Fort Yuma’s guns, partly out of concern over possible Confederate threats during the Civil War). The Colorado II (about 145 feet, 179 tons, same 80 hp engine) continued in service until it was itself dismantled in 1882.
The Colorado I thus marked an important transition: the shift to sternwheelers better adapted to the Colorado, the growth of Johnson’s profitable river trade, and the reuse of machinery that extended the company’s operations. Commercial steamboating on the lower Colorado continued for decades (peaking and then declining with the arrival of railroads in the late 1870s and the eventual blocking of the channel by Laguna Dam around 1909), but the Colorado I was a foundational vessel in that era.