Onboard as the crew launches its commission

It was at just such an occasion that the singer, musician, composer and broadcaster uttered the words "We must do this again" that led to the New Music Biennial commission Aiseag (The Ferryboat), which has consumed Kennedy and her creative partners over the past 15 months.

The piece, which has been devised by Kennedy and her husband, sound engineer Nick Turner, Canadian composer Scott Macmillan and Gaelic poet Aonghas MacNeacail and involves traditional musicians from the Highlands and Cape Breton, field recordings, a string section and Inverness Gaelic Choir, has enjoyed a successful world premiere in Seall on the Isle of Skye and an enthusiastically received second performance at London's South Bank Centre that exceeded all expectations in terms of attendance.

So the pressure's off to some degree. But there's still the Inverness performance, at Eden Court Theatre this Friday, as well as the Glasgow Royal Concert Hall one on Saturday to look forward to and speaking down the line from her home in Ardgour, Kennedy is sounding somewhere between excited, elated and panic-stricken.

The seeds of Aiseag were planted when Scott Macmillan, who was commissioned to write the music for The Bridge Rising documentary of the Skye Bridge tolls protests, arrived in Scotland to record a "real instruments" version of his soundtrack at Kennedy and Turner's Watercolour studios at the end of 2012. The trio's expressed wish to work together again came sooner than they expected when Kennedy's proposal to chart the connection between ferries and the Gaelic diaspora in Canada in words and music was chosen in April 2013 as one of the PRS Foundation's 20New Music Biennial commissions for the Commonwealth Games.

"When Scott was recording at Watercolour he'd said he was interested in working with the Gaelic language," says Kennedy. "Ferries are my little passion, the most relevant one being our local one, the Connal ferry, and when we brought Aonghas onboard and asked him to write the central poem, two things happened. It turned out that we all had our own ferry stories, Aonghas's was pretty graphic, and instead of producing one poem, Aonghas delivered 12 and they were all glorious."

Ferries, says Kennedy, have their own music and Turner set about recording the sounds of the Connal Ferry while ideas were exchanged between Kennedy and Macmillan via Skype and emailed music files. The only time the four protagonists met was for three hours at Kennedy's mother's house in Glasgow when Macmillan came over for The Bridge Rising's premiere screening during Celtic Connections in January.

Kennedy has previous form in an epic musical production with her Lasair Dhe, which featured the Gaelic group Cliar working with massed Gaelic choirs, and as a result of that she was able to call on Inverness Gaelic Choir knowing that, as she says, "they would probably be up for another bonkers project." They have also proved extraordinarily resourceful when it comes to getting themselves around the country.

"Everyone involved has proved the meaning of that marine term 'crew,'" she says, adding that once the Inverness and Glasgow performances are out of the way, she and Macmillan might turn their attention to taking Aiseag to Canada. "Logistically it's quite a thought but there are all sorts of aspects we could tap into. I'd certainly love to give it a specifically localised Canadian spin and it would be inspiring to work with Scott again."

There's a Canadian connection also in The Girls Who Wished to Marry Stars, another of the New Music Biennial commissions, which plays at Glasgow Royal Concert Hall on Friday and which features saxophonist Trish Clowes with her jazz-classical ensemble Tangent, experimental vocal trio Juice and three dancers.

The piece has been developed from a Native Canadian folk tale by Luke Styles, whose busy schedule has seen him also complete recent commissions for horn virtuoso Kira Doherty and clarinettist Timothy Orpen, and offers Clowes a new departure.

"I know Luke's work well because we've organised the Emulsion festival together in East London since 2011," says Clowes, a BBC Radio 3 New Generation Artist. "But although I've always been interested in dance because my mum trained as a dancer, I hadn't actually worked with dancers before. So that's been exciting."

Clowes' group expands and contracts to suit various assignments and in this instance will be a quintet, featuring cello, saxophone, guitar, bass and drums.

"I still think of it as a jazz quintet," she says, "because the cello can be a frontline instrument as well as blending in well with the bass. And although we're working from very specific written material, there are spaces for improvisation and I enjoy working with a storyline and having that influence my playing."

The New Music Biennial is at Glasgow Royal Concert Hall on Friday and Saturday as part of the Games cultural programme.