The hold of a whaleship was divided into upper and lower decks. The upper of these decks was known as "tween decks" (between the lower hold area and the top deck). On the outbound part of the voyage, the casks stored 'tween decks were filled with provisions. The fore-tween deck was located aft of the forecastle and before the blubber room. This area sometimes held several large metal tanks called "coolers". The freshly boiled oil was stored in these until cool enough to put into the wooden casks and not swell the wood. It provided inside workspace for the cooper and carpenter. This image is aboard the whaler Charles W. Morgan at Mystic Seaport.