Ed Sheeran is less than a month away from completing his mathematical album equation with – (Subtract), and on Friday (April 21), he dropped the album’s opener.

“Boat” serves as a metaphor for depression, according to the singer, and its corresponding music video cements the message with its turbulent seaside landscapes. “‘Boat’ is the first song I wrote and finished for Subtract, it’s where it all began, and a good way to kick off the album,” Sheeran wrote on Instagram announcing the single earlier this week.

The song follows lead single “Eyes Closed” as the second offering from the upcoming album, which is set to arrive in full on May 5 as the final chapter of the mathematically themed albums he began with 2011’s + (Plus).

“I had been working on Subtract for a decade, trying to sculpt the perfect acoustic album, writing and recording hundreds of songs with a clear vision of what I thought it should be. Then at the start of 2022, a series of events changed my life, my mental health, and ultimately the way I viewed music and art,” Sheeran previously shared about Subtract.

Two days before the album arrives, the four-part documentary Ed Sheeran: The Sum of It All will begin streaming on Disney+ starting May 3, featuring never-before-seen personal archive clips, interviews and performances.

Watch the “Boat” music video below.