The US Coast Guard is investigating the claims of Midshipman X — the anonymous US Merchant Marine Academy senior who detailed her rape aboard a ship during an at-sea training programme.

"The Coast Guard is currently investigating this incident and cannot comment on the details of ongoing investigations," the agency said in a statement to TradeWinds.

"Sexual assault is a serious crime and the Coast Guard investigates each and every allegation within our jurisdiction.

"We encourage any victim to contact the Coast Guard Investigative Service ... or any Coast Guard Unit to file a report."

In September, Midshipman X wrote in an online post that, at 19, she was raped by a 60-year-old assistant engineer after she was pressured into drinking with her shipmates during Sea Year — the period where academy students are put on ships to gain crucial onboard experience.

She said she woke up the next day with bloody sheets and vague memories of the alleged assailant forcing her to kiss him and perform oral sex on him.

She also said at least five more of her female classmates — 10% of the women in the academy class of 2022 — have been raped during Sea Year.

Maersk Line Ltd, the operator of the unspecified ship where the alleged rape occurred, is doing its own investigation into the incident and suspended several of the then-officers.

The incident described in the post was denounced by the US Department of Transportation, which oversees the academy, shortly after it gained traction online.

Deputy secretary Polly Trottenburg and Maritime Administration acting head Lucinda Lessley said they would "swiftly and resolutely" address the issue.

"Providing resources to students after these events happen is not enough," they wrote in a letter. "We must prevent them from occurring in the first place."

Senator Maria Cantwell and Representatives Peter DeFazio and Salud Carbajal have since issued statements calling on the Department of Transportation to look into the issue of sexual assault.

The academy's alumni association said it would begin adding #womenbelongatsea to all of its social media posts in support of Midshipman X, with president James Tobin saying "if one of us is hurting, we all feel her pain" in a statement announcing the initiative.