Sailors, when first base becomes tense part of dock? (6)
I believe the answer is:
stamen
'part of dock?' is the definition.
(dock is a type of plant)
'sailors when first base becomes tense' is the wordplay.
'sailors when' becomes 'amen' (I can't explain this - if you can you should give a lot more credence to this answer).
'first' says to put letters next to each other.
'base' suggests the final letters (I've seen 'base of' mean this).
'tense' becomes 't' (abbreviation used in many dictionaries).
The last letter of 'becomes' is 's'.
's'+'t'='st'
'amen' after 'st' is 'STAMEN'.
(Other definitions for stamen that I've seen before include "The pollen-bearing organ of flowering plants" , "Flower's pollen carrier" , "Pollen producer" , "Pollen-bearing part of a flower" , "Bit of a bloomer" .)