How One Ship Carries Another: The Secret Operation Behind GPO EMERALD

The first thing that caught my attention wasn’t the ship itself.

It was the sight of welding taking place in the middle of the ocean, on the open deck of a vessel.

Then I noticed something even more extraordinary.

The vessel being repaired wasn’t part of the ship at all—it was NOSTAG 10, another ship, resting on the deck of GPO EMERALD.

The scene looked like a secret operation taking place in the middle of the ocean.

In reality, it was one of the maritime industry’s most remarkable engineering operations.

GPO EMERALD is a semisubmersible heavy-lift vessel designed to transport some of the world’s largest floating structures.

On this voyage, she was carrying NOSTAG 10, a cable-laying vessel built to install subsea power and communication cables that connect our modern world.

Using authentic drone footage, this documentary explores the remarkable engineering behind this unique transport operation.

By flooding massive ballast tanks with seawater, GPO EMERALD lowers her cargo deck beneath the surface, allowing enormous vessels to float aboard before being lifted completely clear of the sea.

Some engineering processes cannot be filmed directly beneath the waterline, so a small number of illustrative visualizations are included to explain how semisubmersible heavy-lift operations work. These sequences are intended solely to illustrate the engineering principles involved and are not intended to depict the actual cargo featured in this documentary.

For many years, I have filmed commercial ships from the air, focusing on their beauty and scale. With my new THE STORY BEHIND series, I wanted to go beyond cinematic aerial footage and reveal the engineering, purpose, and hidden stories behind these remarkable vessels.

I hope this film offers a new appreciation for one of the maritime industry’s most impressive engineering achievements.

Special thanks to fellow creator amSeehafen for beautifully capturing NOSTAG 10 from ground level, providing a complementary perspective to this documentary.

Filmed by: OCEANCRAFTS Motion Gallery

Aircraft: DJI Mavic 2 Pro