It may form a strong attachment to a craft (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
barnacle
'it may form a strong attachment to a craft' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for barnacle that I've seen before include "Sea creature - lean crab (anag)" , "A shellfish that sticks to objects under water" , "hanger-on" , "underwater attachment" , "Crustacean that attaches to underwater surfaces" .)