At least in the period of time I study and the navy I study, this is essentially accurate. On any ordinary day, the morning watch would as a matter of course wash the ship's decks with seawater and scrub them with sand or grit and large stones (called "holystones" because they resembled Bibles) to remove stains and dirt, then flog them dry with swabs. Throughout the day the officer on watch might call for sweepers when some portion of the ship's routine led to the decks being dirtied or fouled. The RN did this as part of a considered policy to keep ships clean, to combat disease, which could rapidly spread on ships packed with men. This was not a trivial exercise -- an example that comes to mind is the failure of a Franco-Spanish expedition in the summer of 1778 to seize Portsmouth, wherein the allied fleet could have potentially mustered 66 ships-of-the-line against 30 British; French incompetence in the dockyards delayed the fleets from combining, and filthy ships meant that disease killed 8,000 French sailors.