“The sailboat crew were either unable to avoid collision” or they could have been down below with Theros on automatic pilot, an anonymous source told Saltwire.
The Canadian coastguard and military aircraft have not spotted wreckage or any sign of the boat, Saltwire reports.
In a video posted to their YouTube channel, Theros Adventures, the pair explained how their trip – dubbed the Green Odyssey – would rely on sails, solar panels, batteries and an electric engine repurposed from a car.
“We’re doing everything we can to show that you can travel without burning fossil fuels,” Mr Clibbery said in the video, posted on 12 April.
“It’s probably the biggest adventure of our lives so far,” Ms Packwood added.
The pair met by chance in London in 2015, when Mr Clibbery, a retired engineer, was preparing to donate a kidney to his sister.
They married in Canada on their yacht a year later, before affirming their vows in a traditional handfasting ceremony at Stonehenge in 2017, according to Ms Packwood’s personal blog.
Their story was featured in a 2020 “How We Met” article in The Guardian.
Ms Packwood, originally from Long Itchington, Warwickshire, had worked in Rwanda with the UN after the 1994 genocide and had extensive experience as a humanitarian.
In what would be their final post on 11 June, the pair wrote on Facebook: “Captain Brett and First Mate Sarah set sail on the 2nd leg of The Green Odyssey on board Theros – GibSea 42 foot sailboat. Powered by the wind and sun. Heading east to the Azores.”