Donald Duck can write a cheque?

Strange question.

Just finishing serge testas book, 500 days.

On page 154 he is sailing into a strong headwind and out of nowhere is the following sentence.

I went to sleep and woke up when i found out that Donald Duck could write a cheque; it was midnight and time to turn again to head back to the island. A square rigger sailed past, followed by a steam ship with Donald on it.

wtf?

Is that some sort of sailing term? Or is serge sleep deprived and losing it?

 

Or is serge sleep deprived and losing it?...yep....we often have little "friends" aboard with us you know....