Intro:

A5 E5 A5 x2


Verse:

A5                                   E5  A5
Fifteen men on the dead man's chest

A5                                         E5  A5
Drink and the devil had done for the rest.

D5                             A5
The mate was fixed with the bosun's pike

         D5                      A5
and the bosun brained with a marlin-spike.

    E5
Cookie's throat was marked belike


Ref:

A5
It had been clutched by fingers ten.

E5
And there they lay, all good dead men,

A5
Like break o' day in a boozing den

E5                        A5
Yo-ho-ho and a bottle of rum!

Intro-thingy again

That's all you need for the song! The rest of it is just the same. Atleast now it should 
easier for you to listen to the song and put in the right chords.