Sir John Hawkins ( also spelled as John Hawkyns ) ( Plymouth 1532 â `` 12 November 1595 ) was an English shipbuilder , merchant , navigator , and slave trader . Admiral Sir John Hawkins ( also spelled as John Hawkyns ) ( Plymouth 1532 â `` 12 November 1595 ) was an British shipbuilder , naval administrator and commander , merchant , navigator , and slave trader .