"Lash your equipment down securely, it's going to be a rough ride," warns the skipper. Oh, bugger - I'm faced with a length of string and the prospect of breaking every fingernail longer than a millimetre.
     "And if you can't tie knots, tie lots," he advises, casting a distinctly unimpressed eye over my girlie efforts.
     The sea outside Portland Harbour looks as if it's boiling, the wind is cold enough to rip skin off and the Coastguard is issuing a gale warning over the radio. Anyone with an ounce of sense is tucked away in a harbourside café with a large cream tea. We're going diving.
     It's that UK diving phenomenon: Easter fever. Sticky-palmed and gagging for a sea dive, it will take more than Arctic temperatures, lashing rain and severe seasickness to deter us. Gosh, we're hard.
     Or so I like to think, as I snuggle down in the spacious cabin of Skin Deep. Actually I'm here because I'm far too spoiled and selfish to be dragging the club RIB around and attempting to crawl my way up Chesil Beach in dive gear.
     Ian Taylor, the skipper, remains resolutely cheerful as we plough through seas that could qualify for a remake of The Perfect Storm, and once we're past the Bill the sea flattens out, just as he promised us it would. Magic.
     The diving itself is, well, a bit snotty. Dark at 30m and so cold that my fingernail-less fingers are in pain. But everyone surfaces wearing the expression of drug addicts who have just acquired a fix. Ah! The luxury of a lift to get me back on board, and a hot cup of tea.
     No such luck for a hapless bunch of RIB divers who have wedged their shot firmly into the wreck and appear to be about to burst into tears.
     Now if I was a skipper, my instinct would be to steam merrily away, tea in hand, leaving them to reflect on their penny-pinching failure to book themselves onto a proper boat.
     Ian does the opposite. He goes over and rescues their shot for them. Outrageous! Such selfless acts of kindness are seriously endangering the traditionally hard-nosed image of UK skippers.
     Despite years of being regarded as gruff, taciturn and smelling faintly of diesel, diveboat skippers cope resolutely with the unpredictable nature of UK weather and UK divers. When it comes to national treasures, you can keep Maggie Smith and Ena Sharples; skippers are the real deal. Some of them even wear the same cardigan as Ena...
     Returning after the second dive, a red emergency flare is sighted over the shoreline. A small RIB is being tossed like a toy in thundering surf, with three drysuited divers clinging to the ropes. The engine has died (ie, run out of petrol), the tide is coming in and even though they've evicted their dive kit, the boat is too heavy for them to haul up the beach.
     Ian informs the Coastguard and carefully edges Skin Deep close to the shore to throw a line to the RIB. "Some people will do anything to get onto Skin Deep," quips one of my fellow-divers as the RIB and its boat-handler are brought alongside. Absolutely.
     It's too rough to tow the RIB back round the Bill: "We need volunteers to haul it up Chesil Beach," says Ian, as the club boat-handler looks down at his feet. Inspired by the example of the skipper, how could we refuse?
     So, much against my nature, I found myself helping to heave a monstrously heavy RIB up the steep pebble slope of Chesil Beach to help out a bunch of divers I'd never met. Believe me, if I hadn't broken all my fingernails earlier, heads would have rolled.
     "This isn't going to do your hard-nosed bitch image any good at all," observes Marky Mark as we put on our fins to swim back to the boat.
     I can only blame the skipper.