Crude painting in crate finally fished from river (4)

I believe the answer is:

daub

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'crude painting' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for daub that I've seen before include "Smear; plaster" , "Carelessly spread (paint)" , "Smear; bad painting" , "Crude painting" , "Coat with plaster" .)

I've seen this clue in The Independent.

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