all at sea

Puzzled, perplexed, or completely confused (about a subject or some task at hand). I tried to do well in this class, but I've been all at sea since we started.

all at sea

BRITISH or

at sea

COMMON If someone is all at sea or is at sea, they are very confused by a situation and do not understand it. While he may be all at sea on the economy, his changes have brought the West real and lasting political benefits. This was a massive success for a party that, two years previously, was all at sea. Note: The reference here is to a ship or a boat that has got lost.

all, completely, etc. at ˈsea

confused; not organized: We’re still completely at sea trying to understand the new regulations.

at sea, to be/all

To be bewildered, to have lost one’s way. Presumably it reflects the idea of literally having lost one’s bearings while at sea. It was so used by Dickens and other nineteenth-century writers.