Mary Rose sailors ate diet of salt beef and biscuits, bone analysis shows.

https://www.telegraph.co.uk/news/earth/environment/archaeology/9310778/Mary-Rose-sailors-ate-diet-of-salt-beef-and-biscuits-bone-analysis-shows.html

Ships Biscuit.

I have read several recipes for ships biscuit but none of them appear to use the constant kneading or "knocking down" method. Somewhere in my memory I seem to recall that this kneading & knocking down (pounding with the side of a clenched fist) was an important part of making ships biscuit. Anyway, here are the links to three articles on this biscuit.

Ship’s Biscuits made by Jeff Pavlik, as featured in John Pavlik, “‘Consisting Merely of Flour and Water’: Reproducing the Eighteenth-Century English Biscuit,” Journal of the Early Americans 1, no. 11 (April/May 2011), 7-11.

http://csphistorical.com/2016/01/24/salt-pork-ships-biscuit-and-burgoo-sea-provisions-for-common-sailors-and-pirates-part-1/

http://www.westfordminutecub.com/resources/Biscuit+Recipe.pdf

http://colonialbaker.net/A%20Summary%20of%20Reproducing%20the%2018th%20Century%20English%20Sea%20Biscuit.pdf

http://www.theoldfoodie.com/2013/04/ships-biscuits.html

Succariebread, Field provisions of the 1718 campaign

https://historyhysteria.wordpress.com/2016/02/10/succariebread-fieldprovisions-of-the-1718-campaign/

Making Ship's Biscuit. Video.

By showing this video I am by no means recommending or promoting this trader or his products, but I think this video is done well and worth watching.