From Longman Dictionary of Contemporary Englishpush the boat outpush the boat outBritish English informalSPEND MONEY to spend more money than you usually do, on something special Push the boat out and get tickets to the theatre or ballet. → push
Examples from the Corpus
push the boat out• Leaving Joe and his son to return to Fancy, we pushed the boat out to sea and ploughed down to Richmond. 