Colloquially; feeling stuck in a project, unable to proceed.
Yes, well - living on an island it should be fairly easy to take a picture of a windless sea and go with something like the original definition. Yes? No. I have, rather, been in the doldrums (second meaning) as the weather has made it impossible for me to proceed.
So - firstly a picture from earlier this year which I think does illustrate what the sea is like in the doldrums;
That was one of those March days we had stolen from summer.
This is what our sea has been like for days... good weather to not be on the boat.