I'm sure someone will give you an answer, but although we don't all do the Times crossword it doesn't mean we can't solve the clues. However, we do need, as a minimum, the clue and preferably any placed letters as well. Many thanks.
Hi there. Just confirming that 13d is ABOVE WATER, as you suspected. Explanation is .. VEW ('sight' = 'view' less the 'i') inside A BOATER ('a cuiser').
In response to Diana\'s question about whether 4D could be \"demure\", it is actually \"demurs\" (patient investigator = DR.(DOCTOR)which contains
EMU (one grounded) + S (beginning to search, all of which makes \"objects* (DEMURS))