Anne, It's one of the old traditions of the RN. If you were teatotal and didn't take your rum or grog ration you also were paid 3p a day extra.
In old times sailors grew a pigtail and tarred it, hence the broad collar and the name "Jack Tar".
It's considered bad luck to whistle aboard ship, superstition had it you could whistle up the wind - a gale; but there is a practical reason. A lot of orders were transmitted by the use of the Bosun's Call, a type of whistle, and Bosun didn't want any one getting confused by someone's aimless tootling.
Sailors wore an earring so if they fell into the oggin St Peter could grab them by it and keep them afloat till rescued.
Cloth was sold by the Ell, the distance between your sternum and your fingers at the end of your outstretched arm. (Never buy cloth from a shorty
) Jack simply folded the cloth in half, cut halfway up the middle and stitched in the legs and side. Cut a bit off for braces and there's your bellbottoms, or Dutch Britches as they were in the 17th century.
Splicing the Mainbrace was such a pain the tars involved got an extra tot of rum. So in respect of heroic or tough conditions, or a visit from a VIP became an excuse to "Splice the Mainbrace" everyone getting a tot.