Taking the bare essentials, head off on a ship of legends (4)
I believe the answer is:
argo
'ship of legends' is the definition.
'Argo' can be an answer for 'ship' (ship in Greek myth). I'm unsure of the 'of legends' bit.
'taking the bare essentials head off on a' is the wordplay.
'taking' is an insertion indicator.
'the bare' becomes 'rg' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'essentials' indicates anagramming the letters.
'head off' suggests taking the first letters.
The first letter of 'on' is 'o'.
'o'+'a'='oa'
'oa' is an anagram of 'ao'.
'rg' going within 'ao' is 'ARGO'.
Can you help me to learn more?
(Other definitions for argo that I've seen before include "Old sailing vessel" , "ancient boat" , "Old craft" , "Fabulous ship" , "Old ship" .)