Motoring the canals of Greater London provides a charming backdrop to “Anchor and Hope,” a generally pedestrian romance about a lesbian couple’s struggles to have a baby.

Carlos Marques-Marcet (“10,000 Km”_ has lovely locations and a good cast that you can’t blame him for the funereal saunter that he uses to pace their story. It doesn’t help that this general scenario has been the subject of lots of episodic TV (more TV shows than movies) so that every obstacle and setback feels familiar to the point of worn out.

We meet Kat and Eva (“Harry Potter” veteran Natalia Tena and Oona Chaplin of “Game of Thrones”) as they bury their cat. Chorizo was so beloved that they tie up for the burial, and get Eva’s “wacky” mother (Geraldine Chaplin) to chat some Native America/Buddhist mashup gibberish over the dear departed.

And that sets Eva off. She wants her children to know “the full extent of the madness” of her odd, funny and unique mother. She’s 30ish and figures the time is now. The plan? Get their mutual friend, the Barcelona babe-magnet Roger (David Verdaguer of “10,000 Km” and “Summer ’93”) to come stay with them a couple of weeks — and for ONLY a couple of weeks. A little artificial insemination, and voila, they’ll start a family.

But Kat, who pilots the boat, lives in her leather jacket and loves Eva madly, isn’t sure about all this — especially as “the plan” was discussed and approved in drunken reverie.

Roger? Hey, as long as there’s porn he can watch in the head (toilet) while doing his part, he’s along for the ride — for however long it takes.

Marques-Marcet, who co-wrote the script, gets the most out of this promising set-up and comically game cast in the film’s earliest scenes. Roger, the ladies man, wears a Wolverine beard and a leer that no mere Londoner can resist — apparently.

He speaks English to Eva (mostly) and Spanish to his old buddy and bar-cruising wing-woman Kat, and it’s rare that he’s not joking around, even about the job at hand.

“What’s funnier than a dead kid? A dead kid dressed like a clown.” It’s funnier in Spanish.

Want some food?

“English food? No thanks.”

There is drinking and inseminating and nostalgic sing-along and bump and grind sessions to Inner Circle among the festivities. Roger goes ashore to charm the local ladies, and his bubbly carousing sucks Kat back into an old life that Eva was sure she’d left behind.

But the fun fades as the film, broken into titled chapters — “I: We Can Get Another Cat,” “III, A Kidney Bean,” etc — and “Anchor and Hope” drifts and then runs aground. Cute moments of baby proofing the vessel (boats are built somewhat baby-proof), emptying the bar, for instance, are skipped past as Eva and Roger get “Oh, Susannah” sentimental at the piano.

The players are pretty good, with the Elder Chaplin and Tena standing out, and Verdaguer making a fine rascal to the extent the script lets him become one.

The boat-handling, including hand-turning the ancient canal locks, is a great detail, the shoreside scenery lovely even when it is tumbledown industrial.

And there are laughs in Eva’s political arguments for reproducing.

“Homophobes and religious fanatics are having babies. Reasonable people have to have them, too!”

Roger’s many conquests include Jinx, a black woman (Lara Rossi) who comes back to the boat only to see her lover disappear into the head for another shot at making a deposit for Eva. Jinx, who endures the Spaniard’s comparisons of her to chocolate, just rolls with it.

“Listen to him go!”

“You get used to it.”

The pre-insemination interview Eva carries out (“Do you have any psychopaths in your family?”) is a tired device in such movies and isn’t funny here.

That’s the case with too much of “Anchor and Hope” to make it worth recommending. Sure, there’s a novel setting and hot sex, here and there. But the talk turns toward the tedious and the jokes, the situations and the romantic longing never draw us in. The viewer isn’t so much a part of the story as a bystander, curious and occasionally titillated, but rarely moved.

MPAA Rating: unrated, nudity

Cast: Natalia Tena, Oona Chaplin, Geraldine Chaplin, David Verdaguer, Lara Rossi

Credits:Directed by Carlos Marques-Marcet, script by Jules Nurrish and Carlos Marques-Marcet. A Wolfe release.

Running time: 1:53