How smooth and shiny keels can be! (5)

I believe the answer is:

sleek

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'how smooth' is the definition.
'sleek' can be an answer for 'smooth' (similar in meaning). I am unsure of the 'how' bit.

'shiny keels can be' is the wordplay.
'keels' anagrams to 'SLEEK'.
But, I'm not sure how the anagram is indicated.

'and' acts as a link.

Can you help me to learn more?

(Other definitions for sleek that I've seen before include "Velvety" , "Aerodynamic, streamlined" , "Pleasingly smooth" , "Lustrous" , "Smooth and shiny" .)

I've seen this clue in the Evening Standard.

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