The yacht would be an expensive one.

The deck fittings were elaborate.

A glance into the captain's cabin revealed it to be fully furnished, with a chart and a sextant on the mahogany desk.
"Where's the bedding for this stateroom ?" asked one of the men.
"I got a prop-rustler after it," one of the others informed him.
They strolled aft and paused by an iron standard ingeniously swung from the deck.
"That's Burke's idea," said one of the men.

"I hadn't thought about a steady support for the camera; of course if we stood it on deck it would rock when the ship rocked and we'd get no motion.

So Burke figures this out.