Last Night's TV: Chris Ryan's Strike Back, Sky 1Timothy Spall: Somewhere at Sea, BBC4The Boats That Built Britain, BBC4

What I want to know is who kidnapped Jed Mercurio and where are the ruthless bastards keeping him? He's an interesting and talented writer, after all, and the only explanation for the appearance of his name on the credits of Chris Ryan's Strike Back – a terminally dim-witted bit of SAS combat porn – is that he's being held in a basement somewhere and forced to write this gibberish at the point of a gun. It's at times like this that the Writers' Guild of Great Britain needs to be able to call on an elite force of its own, a team of crack dialogue boys who could blow the seals on Mercurio's contract and extract him to a place of safety, where he could be debriefed by trained trauma counsellors. Failing that, though, we're just going to have to look on helplessly as the humiliation continues.

I'll come clean. I quite like first-person shooter video games and have a slightly shaming susceptibility to helicopter insertions, night- vision sights and the macho clatter of an automatic weapon being cocked. I do prefer to play with a game controller in my hand, though, rather than simply watch over someone else's shoulder, which was what the opening section of Strike Back was like. They seemed to be playing on novice level too. Sent in to Basra to rescue a kidnapped British industrialist, our boys encountered an enemy who generously took their time about shooting back, despite the fact that the SAS men had helpfully attached torches to the front of their weapons to give them something unmissable to aim at. And then, when it was all going swimmingly, John Porter froze, and instead of taking out a young suicide bomber with a head shot, saved his life by cutting the wires instead. Three of his colleagues were killed and John got a ticket to a dead-end job in car-park security and a mullet haircut that was an eloquent metaphor for his battered self-esteem.

Luckily for John, a former foreign secretary's daughter had been kidnapped and, wouldn't you know it, the ringleader of the gang was the very suicide bomber whose life John saved all those years ago. Before you could say, "You can't park here, mate", he'd been trained up to infiltrate the group and win over the jihadi who – according to the ancient Arab code – owed him a debt of honour. If you think that this is a fragile peg on which to hang a critical rescue mission then you may have the wrong sort of mind to fully appreciate Strike Back, an entertainment that requires the complete suspension of all questioning faculties. If, on the other hand, you like explosions and Spooks-like operation centres and people barking things like "Because we've only got one upload we can't analyse the back-scatter!" you may have fun. For myself, the only thing I want to know is which brand of mobile phone the kidnapped woman was using. As she was seized she managed to surreptitiously capture a photograph of the man who was kidnapping her – an image that turned out to be of such lustrous quality that you could put it straight on the front cover of Vanity Fair. It was about as believable as everything else in the drama.

Sea Fever, BBC4's little flotilla of programmes about our maritime heritage and culture, last night turned up a little gem in the shape of Timothy Spall: Somewhere at Sea, the first of a three-part series that accompanies Spall and his wife, Shane, on a genial potter around the coast of Britain in a converted barge. "Potter" isn't the technical nautical term, but then the whole charm of the programme is that Spall looks as if he's out of his depth whenever he's more than 100 yards from the coastline. He began with briney clichés – of the type we've already encountered in other contributions to the series: "The sea is a leveller, an unpredictable element," he said. "If you weren't afraid of the sea, you'd be a fool." But almost immediately the warmth of his character took over – jolly and self-deprecating and sensibly wary of any wave over one-foot high.

Essentially, his boat, The Princess Matilda, is an ocean-going caravan, driven by someone who's very happy to troll along in the slow lane, and who can find a silver lining even when he's marooned in a Cornish estuary for months because of bad weather. "That's the wonderful thing about a British summer," he said, staring out at a sky like pewter. "Just how many shades of grey you get." He also delivered what must be the funniest ever reading of the Beaufort scale, voice rising from a gentle whisper to a hysterical typhoon as the wind strength increased. It's like a Mike Leigh drama from which all the angst and pain and disappointment has been drained away, leaving only optimism and affection and a large pleasure in small things.

The Boats That Built Britain works well too, delivering a nostalgia not only for the vessels of the past but also for the presentational style of yesteryear. Tom Cunliffe – a man with a sea dog's neckerchief – clearly knows his stuff. But his exclamation-mark spattered delivery also seemed teasingly familiar. I couldn't place it immediately and then I got it: it's as if John Noakes has been preserved in brine for the past 30 years and a Blue Peter is flying from the stern again.