While Leviathan has damaged ports and not attacked individual ships, Wildbow has commented that the impact on shipping likely incentivized the United States to help revive Detroit's industries. This is part of a wider trend of Endbringer attacks necessitating the economic independence of countries.
↑◈ HORIZON; Maria Whitworth Classification: Thinker 3; Striker 1-12* Maintains one of three types of enhanced perception at any given point in time. Has an explosive touch linked to perception.
Disposition: Protectorate Location: DEPT 64 (Anchorage) as of 1-1, 2012, previously of DEPT 18 (Detroit) - PRT Quest (Anchorage)
↑"Where I went to school, people never would have let that slide."
Horizon removes her leses, her mask, and lowers her hood. She is blonde, her features not unattractive, but perhaps a bit on the severe side. A triangular face with a sharp chin, defined cheekbones, and dark eyebrows contrasting her light colored hair. She has 'hood hair', for lack of a better term, her hair pressed flat against her head. She uses her fingers to fix it some, scratching at her scalp at the same time.
"Detroit, was it?" you ask.
"Good recollection. Yep."
"And your partner was alright with the move?"
"My husband is a musician. Works online, does soundtracks for independent filmmakers and video game creators, weeks of having nothing to do, then days or weeks of frenetic activity. So long as he has his studio and a little bit of freedom, he's okay with whatever. Your... wife, I'm assuming?" - PRT: Department Sixty Four [Worm Quest] - Page 26
↑I joined the others, my heart was pounding with enough force that the thumps rocked my entire body. Tecton was closest to the stage, followed by Grace and Wanton. The core team members, the veterans. Veterans in one sense. Wanton didn’t have half the field experience I did, even with our sustained campaign against the local villains, starting to help out in Detroit and trying to deal with that one jerkass in Milwaukee who we hadn’t yet managed to pin down. Tecton and Grace were a little more seasoned, but not by a lot. - Excerpt from Scarab 25.4
↑Shipping wasn't hurt because of boats - Leviathan tended to have periods of activity where he'd attack a city, then retreat to deep water. Boats weren't really hurt, except incidentally.
Shipping was hurt because ports in target cities and port cities near the targets were left devastated. (Also port cities visited by Simurgh/Behemoth/Tohu Bohu/Khonsu) Shipping still is a thing in the Wormverse. - Wildbow on Spacebattles
↑Detroit GM discussions with Wildbow (paraphrased)