Wooden Flagon (serving jug) from the MaryRose,, Beer was a very important part of the sailors diet. It contains lots of calories and is a good source of vitamin B. The navy needed to buy huge amounts of beer to keep the ships' crews happy. A lot of the navy's beer was made in royal breweries. In 1525 there were at least five royal breweries in Portsmouth, they were called the Rose, Lyon, Dragon, Whiteharte and the Ankre (Anchor).