Jason Best and crew enjoy a spot of partying aboard the good ship Besso during the final stretch of the Round Britain and Ireland Challenge

 There’s a festive mood on board Besso today: it’s Paul’s birthday. And despite the rigours of life at sea, we’ve celebrated in grand style. We may not have had any champagne to crack open, but with spirits running high we’ve plenty of fizz of our own.

The crew, you’ll be impressed to learn, has gone about its party preparations in the time-honoured maritime tradition of making do with the materials to hand. Seamen on 19th-century whalers created intricate ivory carvings of ships and other bits of scrimshaw. Gin Watch has shown similar ingenuity in fashioning ribald party balloons out of latex gloves.

They’ve come up with a pirate, a punk, an alien and other rum coves, including, inevitably, the rampant embodiment of ‘Spotted Dick’. A ship-made card and a cake baked by Donni, from ingredients scrounged from the galley, have added to the fun.

The humour aboard Besso often verges on the surreal. Indeed, there have been times when it has been so off-beam that I’m convinced someone has switched the pipes in the galley and we’ve been drinking seawater.

So, on balance, it’s probably a good thing that the plan cooked up by Ron as we rounded the Shetlands to invade Muckle Flugga never came to fruition. Ron, our American crewmate, is the ship’s resident humorist, with a droll line in deadpan wit that never ceases to amuse.

The jokes are an important safety valve. When there are 15 of you living for 12 days in a space that’s 22 metres by 5.5, you have to find ways of defusing tension. Given these cramped conditions, not to mention the cold and damp, it’s remarkable that no one on board has had a sense of humour failure. The merriment we’ve created on such an occasion as Paul’s birthday is perhaps the reason why.

Flaking a sail on deck in the middle of a Force 5 will never be my idea of fun, but on this trip I can’t say I’ve been short of laughs.