Has a go at covering up type of sleep produced by old Roman crafty types (8)
I believe the answer is:
Here is my best explanation:
'roman crafty types' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
I also know that 'roman' relates to this answer.
'has a go at covering up type of sleep produced by old' is the subsidiary indication.
I cannot really see how this works, but
'sleep' could be 'rem' (abbreviation for Rapid Eye Movement) and 'rem' is present in the answer.
'has' could be 'tries' (trying is a kind of having) and 'tries' is present in the remaining letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
(Other definitions for triremes that I've seen before include "They had three banks", "Galleys" and "boats".)