Arm-chest

This Disappointment chagreen’d the Ship’s Company, who were very intent upon their Market; which was reported to be an Arm-Chest full of Gold, and kept with three Keys;

Source: wiktionary

[…] as soon as he had taken charge of the deck, he saw Mr. Hayward, the mate of his watch, lie down on the arm-chest to take a nap;

Source: wiktionary

[…] there being no line-and-sinker at hand, I sent Jarl to hunt them up in the arm-chest on the quarter-deck, where doubtless they must be kept.

Source: wiktionary

[…] he stood on his own particular perch behind the mail, beating his feet, and keeping an eye and a hand on the arm-chest before him, where a loaded blunderbuss lay at the top of six or eight loaded horse-pistols, deposited on a substratum of cutlass.

Source: wiktionary