Refusal to approach outsiders on Channel Island building capacious boat (8)

'capacious boat' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'refusal to approach outsiders on channel island' is the wordplay.
'refusal' becomes 'no' (saying no to something).
'to' is a charade indicator (letters next to each other).
'outsiders' means to remove the middle letters (only the letters on the outside of the word remain).
'on' is a charade indicator (letters next to each other).
'channel island' becomes 'Sark' (Sark is one of the Channel Islands).
'approach' with its centre taken out is 'ah'.
'no'+'ah'+'sark'='NOAHSARK'

'building' acts as a link.

Can you help me to learn more?