Sail erratically round the kingdom with a dog (6)
I believe the answer is:
saluki
'a dog' is the definition.
(Saluki is an example)
'sail erratically round the kingdom' is the wordplay.
'erratically' indicates an anagram.
'round' means one lot of letters goes inside another.
'the kingdom' becomes 'uk' (UK is an example).
'sail' anagrammed gives 'sali'.
'sali' placed around 'uk' is 'SALUKI'.
'with' is the link.
(Other definitions for saluki that I've seen before include "Shown [AT CRUFTS]" , "Gazelle hound" , "Tall slender dog" , "Tall breed of hound" , "5 [MANS BEST FRIEND]" .)