Took out sailboat to no wind and then came back in high winds

Took sailboat out to Potomac.  Wind was almost non-existent at the inlet of Herring Creek.  Talked to another sailor while in the river and then wind picked up about a hour into sailing.  Wind got real strong (maybe up to 15 mph) so I let down the main sail and motored back to Herring Creek.  At the dock, I finally added new battens to the mainsail.  Learned from the other sailor that I had a clip holding up the mainsail boom and should let that down when underway.