The rifles in the pictures look like Lee-Metfords they were replaced by the lee-Enfields pre-WW I but were put back into service at the start of WW I do to a shortage of rifles. The RN the early years of WW I used these as well as 7mm mauser rifles made for Brazilian or Chilian warships building in British docks at the start of WW I. They also used some 6.5 mm Type 38 Japanese rifles and some canadian Ross rifles.
Field drill in the RN back then often ment the sailors had to go on a 20 mile or so hike with rifles, ammo ect. this was not popular with with ORs as can be imagined. They also practiced basic infantry tactics in case the ship had to send a landing party ashore. Which did sometimes happen in WW I.