Rebuilt Noah's new ark's helm: praise be! (7)
I believe the answer is:
hosanna
'praise be' is the definition.
(I've seen this before)
'rebuilt noah's new ark's helm' is the wordplay.
'rebuilt' is an anagram indicator.
'new ark's helm' becomes 'na' (I am not sure about this - if you are sure you should believe this answer much more).
'noahs' with letters rearranged gives 'hosan'.
'hosan'+'na'='HOSANNA'
Can you help me to learn more?
(Other definitions for hosanna that I've seen before include "Adoring cry" , "Cry of praise or joy" , "Shout of praise" , "Exclamation of praise to God, from Hebrew" , "Hebrew word in the Bible, an exclamation of praise" .)