My plan was to paddle to the beach just beyond Fevik and have a bit of a swim followed by breakfast. I could then drift back to Grimstad and go to the office straight after lunch.
In the end, I drifted in the other direction to explore lots of little channels and islands near Nedenes and didn't get back until late afternoon. I paid for the trip with a bit of redness of the skin from the sun and wind - my plan for a short trip meant that I hadn't bothered with sun block or a hat.
The swimming part of the plan worked. The beach was a little bit busier than last time I visited; six other people came down for an early swim. The water was reasonably warm and almost completely free of jellyfish.
I passed the beach again on the way back, stopping on the rocks for some lunch. The heat and the sunshine had brought out so many families that there was barely any sand to be seen between the towels and beach toys.
My exploration around Nedenes showed me a third way of getting through to Arendal; it's a slower route but very sheltered and might be useful in bad weather.