composed of oblong panels which could be inserted in grooved steel
uprights when it was desired to close in the interior of the boat.
The motors were very powerful.

In fact, it was just such a boat as was needed on the trip the boys
had in mind. It had done excellent service on the Columbia, and
nothing less could be expected of it on the Amazon. The Wolf, which
was merely a tender, was watertight in construction, being shaped
like a banana, and was towed by the motor-boat. Here the extra
stocks of gasoline, provisions, and ammunition were packed. The
interior of the Wolf was about six feet by eighteen in size, while
the distance from rounded floor to convex roof was about four feet.

On both sides of the interior were gasoline tanks, which also
extended under the floor, lifting the bottom of the interior space
three feet. Above the tanks were spaces for provisions and
ammunition. The space between the tanks and the lockers was about
two feet, and here one might ride in comfort, after getting used to
the rolling of the boat. There were tight glass panels of thick
plate glass at the ends and the top.

Ventilators and loopholes, controlled by wires from the center, were
cut in the ends and protected by sliding covers. Lying in the
passageway, one might look out at either end, and shoot out, too, if
occasion required. When fully loaded, the Wolf was submerged about
half its height. On the top was a staff from which floated an
American flag. The boys were very proud of the Wolf, and Jimmie had
often declared, on the Columbia river trip, that he would some day
take an exciting ride in it.