The last dive boat I slept on was the converted Victorian guano barge mv Diphtheria - a sort of prison hulk for unhinged diving journalists, dodging hurricanes between Cuba and the Caymans.
She was a far cry indeed from the Zsa Zsa Gabor, the luxurious trimaran aboard which I once slouched around the Virgin Islands with a Sea Breeze in one hand and a supermodel in the other.
In reality, the Diphtheria would be more accurately described as a "die-aboard". Nothing was lashed down. The boat would lurch violently at the merest suggestion of a swell, and immediately the air would be thick with flying air cylinders. The tables and chairs - the kind of lightweight garden furniture you would expect to find on a patio in Frinton - would shoot across the afterdeck, gathering momentum until they cannoned into the opposite scuppers, crushing the diners against the rail and drenching them in the explosive coconut spirit which provided the sole consolation in this floating hell.
The air conditioning was powered solely by bilge rats scampering on a treadmill and broke down frequently.
If anything, the diving arrangements were even less sophisticated than the accommodation. Nothing has changed for the Cubans since the Americans stopped their pocket money: the equipment was antique Cold War from the wrong side of the Iron Curtain.
The ancient bottles were made from Russian steel - a material with the consistency of a rusty flapjack. To attach a modern Western regulator required such a jungle of pipes and adapters that by the time you left the boat, you looked like a scale model of the Mir space station.
All of which was in dramatic contrast to the most luxuriously appointed of live-aboards, the Zsa Zsa Gabor.
To enhance what the brochure called the "In-Water Experience", no expense had been spared.
The dive guides, all directly related to Jacques Cousteau, were on first-name terms with most of the larger fauna from Puerto Rico to Curacao.
At the end of the dive, I was whisked straight from the water in the nautical equivalent of a Stannah Stair Lift into a comforting huddle of hired help who relieved me of my gear, dabbed me down with hand-made blotting paper, draped my shoulders with a cloak of musk-scented silk and handed me a cocktail that looked like a 3D Miro.
My suite was designed to elevate gracious living to the very epitome of decadence. My jacuzzi had a glass floor which allowed me to observe not only the reef but also the occupants of the cabin below.
The evenings were spent lingering over fine wines and cognacs while gymnastic students modelled the latest in Brazilian swimwear. It was a far cry indeed from life aboard the Diphtheria, where we had to amuse ourselves with fish fights and projectile vomiting contests.
So what's the lesson here? Simple: that the term "live-aboard" embraces everything from the Titanic to a Liverpool slaveship. A holiday afloat could turn out to be a week of undreamed-of indulgence aboard a gin palace that would make Cleopatra's barge look like a pedalo, or a lifetime chained to the oar of a Roman quinquireme.
Be vigilant. Choose the right boat. If it claims to be a converted trawler, make sure it was converted from a trawler and not into one.
Check the skipper out. Ask if he can swim. If he can't, he's unlikely to understand the mind of a diver. Ask if he's a psychopath. So many are!
Measure your berth. That you should fit in it unfolded is too much to ask - but you really don't want to spend seven nights in accom-modation designed for the Time Bandits.
Cheerio, shipmates.
For more in a similar vein the book Blackford's Diving Life and Times can be ordered from Underwater World Publications, price £7.50 (tel. 0181 943 4288).
