Many of the plot elements you describe seem to fit Sun of Suns (2006) by Karl Schroeder, the first book of his Virga series.

The protagonist, Hayden Griffin, lived in the nation of Aerie, in a giant, 3000km diameter bubble of air floating in space. Nations form around what matter (e.g. asteroids) can be found that are lit by artificial "suns."

Hayden was orphaned when the nation of Slipstream raided Aerie, and grows up partially raised by pirates, motivated to kill the Slipstream Pilot who killed his parents.

At one point he glimpses spy photographs of a giant ship under construction by a rival power, and estimates it is 3km long.

There is a scene where icebergs, that form under the exterior skin of the bubble are dropped on enemy (pirate) ships; this is one of the strongest points of recognition with your question.

There are a lot more plot details available on the book's Wikipedia page.

The U.S. paperback cover has a vaguely similar (in a "squint and look at it sideways" way) composition to what you show, notably the most colourful element being the partially-obscured greenish shape in the middle:

Many of the plot elements you describe seem to fit Sun of Suns (2006) by Karl Schroeder, the first book of his Virga series.

The protagonist, Hayden Griffin, lived in the nation of Aerie, in a giant, 3000km diameter bubble of air floating in space. Nations form around what matter (e.g. asteroids) can be found that are lit by artificial "suns."

Hayden was orphaned when the nation of Slipstream raided Aerie, and grows up partially raised by pirates, motivated to kill the Slipstream Pilot who killed his parents.

At one point he glimpses spy photographs of a giant ship under construction by a rival power, and estimates it is 3km long.

There is a scene where icebergs, that form under the exterior skin of the bubble are dropped on enemy (pirate) ships; this is one of the strongest points of recognition with your question.

There are a lot more plot details available on the book's Wikipedia page.

The U.S. paperback cover has a vaguely similar (in a "squint and look at it sideways" way) composition to what you show, notably the most colourful element being the partially-obscured greenish shape in the middle:

I can't find a cover that matches, but many of the plot elements you describe seem to fit Sun of Suns (2006) by Karl Schroeder, the first book of his Virga series.

The protagonist, Hayden Griffin, lived in the nation of Aerie, in a giant, 3000km diameter bubble of air floating in space. Nations form around what matter (e.g. asteroids) can be found that are lit by artificial "suns."

Hayden was orphaned when the nation of Slipstream raided Aerie, and grows up partially raised by pirates, motivated to kill the Slipstream Pilot who killed his parents.

At one point he glimpses spy photographs of a giant ship under construction by a rival power, and estimates it is 3km long.

There is a scene where icebergs, that form under the exterior skin of the bubble are dropped on enemy (pirate) ships; this is one of the strongest points of recognition with your question.

There are a lot more plot details available on the book's Wikipedia page.

Many of the plot elements you describe seem to fit Sun of Suns (2006) by Karl Schroeder, the first book of his Virga series.

The protagonist, Hayden Griffin, lived in the nation of Aerie, in a giant, 3000km diameter bubble of air floating in space. Nations form around what matter (e.g. asteroids) can be found that are lit by artificial "suns."

Hayden was orphaned when the nation of Slipstream raided Aerie, and grows up partially raised by pirates, motivated to kill the Slipstream Pilot who killed his parents.

At one point he glimpses spy photographs of a giant ship under construction by a rival power, and estimates it is 3km long.

There is a scene where icebergs, that form under the exterior skin of the bubble are dropped on enemy (pirate) ships; this is one of the strongest points of recognition with your question.

There are a lot more plot details available on the book's Wikipedia page.

The U.S. paperback cover has a vaguely similar (in a "squint and look at it sideways" way) composition to what you show, notably the most colourful element being the partially-obscured greenish shape in the middle: