The fuel used was wood, of which there was great abundance along the shore, the hard, fine-grained mesquite making a particularly hot fire.

The routine of advance was to place a man with a sounding-pole at the bow, while Robinson, the pilot, had his post on the deck of the cabin, but the sounding was more for record purposes than to assist Robinson, who was usually able to predict exactly when the water would shoal or deepen.

Later, Ives says: "If the ascent of the river is accomplished, it will be due to his skill and good management." Besides the ordinary shifting of the sands by the restless, current, there was another factor occasionally to guard against.

This was earthquakes.
Sometimes they might change the depth of water on the lower river in the twinkling of an eye.

On one occasion, a schooner lying in a deep part was found suddenly aground in three feet of water, with no other warning than a rumble and a shock.