They are called racks by the passengers.

Among sailors they are known as 'fiddles,'" explained the guardian.
"Yeth, but the thoup will thpill over jutht the thame," observed Tommy from the cabin.
"Your soup will not, for I'm going to eat it," jeered Margery.
Tommy hurried forth, fastening her collar as she walked.

She was taking no chances of losing her supper.
"Speaking of food," reflected Harriet.

"Why can't we take our meats and other perishable things and put them in a pail which we can weight down until it sinks?
That will keep the food cool." "Yes.

But what will you do with it when the boat is moving ?" asked the guardian.
"If I have to row the small boat, and pull the 'Red Rover,' it won't move fast enough to harm the pail," spoke up Jane.