A tattoo is a form of body modification, made by inserting indelible ink into the dermis layer of the skin to change the pigment. Tattooing is a practice that goes back thousands of years to primitive Neolithic tribes. It is known to have been used in Roman times to identify slaves, convicts, and army deserters. During the American Civil War, tattooing began to be seen as a rite of passage for enlisted men in both the Army and Navy. Tattoos were also considered something of a requirement for sailors on long sea voyages in the age of sail as a way to identify the bodies of men who had been washed overboard.
In Popeye media
One of Popeye's more iconic physical characteristics is that of his oversized forearms, which further contain another element symbolic of the character: matching tattoos, undetailed and depicting a pair of anchors. Throughout his screen and comics history, Popeye has been consistently depicted wearing these tattoos - which have only rarely been shown to animate in a cartoony fashion - and they remain largely unchanged, with some exceptions: the live-action Popeye film gave him smaller, more colorful and differently-shaped anchors, while the test footage shown for the upcoming animated feature has him devoid of such iconic elements as his pipe and the tattoos, ostensibly to keep objectionable elements out of the children's film. However, production has been put on hold and no such changes have been made official yet.
Popeye's arm tattoos are some of the elements that distinguish him from his almost-identical father, Poopdeck Pappy, who has been known to shave and draw fake tattoos on his arms in order to be mistaken for his more-famous son. During one such Thimble Theatre storyline, Pappy received a real tattoo of a star on the back of his neck that would supposedly help to identify the 'real' Popeye, yet it was actually Pappy at the time he got it.
Bluto in the animated cartoons has a tattoo that is much more nebulous in character. It depicts a battleship (or a sailing ship as seen in Let's You and Him Fight) that covers much of his pectoral region. It is capable of rising out of the water as an indicator of his ire, firing actual missiles at an opponent, and sinking beneath the waves as an indicator of his defeat. It is not seen much of the time, even in cartoons where Bluto remains shirtless.
The lifeguard from Beach Peach has a tattoo that is similar to Bluto's. Brutus also reveals the tattoo of a battleship in the Popeye the Sailor episode "I Bin Sculpted", but it is located on his right bicep rather than on his chest (in that same fanciful cartoon, Popeye is shown to have a submarine tattooed inside his left bicep with the same interactive missile feature). The Champ in Punch and Judo has a tattoo on his left upper arm that enumerates the challengers he has vanquished.