A few weeks after their appearance on the boat, I meet the group again at Wembley Arena, where they are preparing for their first UK concert the following night.
As the staging - complete with giant LED screens and the group's logo - is set up around them, the six members rehearse synchronised choreography alongside their back-up dancers.
The group consists of main vocalist Sueda Uluca, lead vocalist Lidya Pınar, sub-vocalist Mina Solak, sub-vocalist and main rapper Zeynep Sude Oktay, lead dancer Hilal Yelekçi and main dancer Esin Bahat.
But Wembley is just the beginning of their ambitions.
"After Wembley, we'll manifest Coachella and other big stages," says Hilal Yelekçi, playing on the group's name.
manifest were formed in February last year through the Turkish reality TV talent competition Big5 Türkiye, which saw contestants compete over several months for a place in the group.
They were mentored by established Turkish pop stars, including Gülçin Ergül, a former member of girl group Hepsi, who was also a judge on the show.
The band's rise has been rapid, and they now have more than six million monthly listeners on Spotify.
While in London, they released their first English-language single, TRALALA, which topped YouTube's daily music video chart on its release, ahead of videos from Shakira and Taylor Swift.
The music video was also their first to be filmed outside Turkey, with the group working with a largely British production crew in east London.
"Getting out from that safe zone was a bit stressful for us," says Pınar.
Despite their hopes to perform on British and American stages, they're keen to retain their Turkish identity.
"We want to reach a global audience with our Turkish songs actually, not with English ones," says Sude Oktay.
"We want to teach people to sing in Turkish."
Alongside Turkish girl group Hepsi, manifest cite the Spice Girls among their musical inspirations.
Pınar says her favourite Spice Girl is Baby Spice.
"Because of the pink. I'm pink and blonde, so it's obvious," she laughs.
They have also had the chance to meet one of the world's biggest pop stars, Dua Lipa.
The British-Albanian singer met manifest backstage before watching them perform at her Sunny Hill Festival in Kosovo in July this year.
"She came to our backstage and said a lot of great things," one member recalls.
"We really love her, her songs, her stage presence."
On the day of the concert, there was a sense of excitement outside Wembley Arena as fans wearing manifest-branded headbands and carrying banners gathered.
The crowd was predominantly Turkish women in their 20s and 30s, many dressed in colours associated with the group.
Among them were friends Elif, 31, and Zeynep, 25, both Turkish women living in London, who reflected on the band's past year.
"I don't think I've ever heard of a girl band performing there," says Zeynep.
"I think I was seven when Hepsi were last together. It's maybe a once-in-a-lifetime experience."
Turkish pop star Tarkan previously performed at Wembley Arena in 2008.
For Elif, the concert has a wider significance.
"We are going through difficult times back home. It means girl power and empowerment, and just having fun and being together," she says.
"I feel like back home people came together to support them and criticise the treatment that they were receiving from the government."
Zeynep hopes the group will one day be able to perform freely in Turkey.
"It's great to see them here, but I hope one day they will be back in Turkey and they'll be able to do whatever they want without getting persecuted for it," she says.