Upstairs, in the Horizons lounge on the MS Marina's deck 14, as we wave goodbye to Portugal and prepare to cross the straits of Gibraltar, the ship's captain is hosting cocktails for a gathering of Oceania Cruises' most dedicated guests - those of Diamond status. These are the people who have notched up more than 40 cruising credits.
A quick maths lesson: take a cruise of up to 24 days and you'll earn one credit. Spend more than 55 days at sea in a single stint and Oceania will give you five credits. What this means is these Diamond types have clocked up an impressive 440 days onboard. Yes, 440 days: 62 weeks, or roughly 1.2 years. Who can dispute the human ability to be monogamous? That oft-heard anecdote of high-seas aficionados - "You unpack once but wake up in a different port each day" - is clearly an irresistible formula for many.
Nonetheless, I still felt a slight tightening in my chest as we first approached Marina, docked at a rather charmless port some 45 minutes up the Gironde Estuary from the city of Bordeaux, on a shiny European summer afternoon.
MS Marina is a few days into her 16-day Tastes of Europe journey, largely following the route of the Grand Tour from London to Rome, but with deviations taking in Spain, Portugal and a nanosecond in North Africa's Casablanca.
Something classic seemed appropriate for my initial dalliance with life on the high seas. Likewise, Oceania's Marina, a sleek little number that débuted in 2011 and carries a not-too-terrifying 1250 guests, seemed like a good fit for a reticent cruiser.
Marina, like her sister ship Riviera (launched in May 2012), is billed as the floating queen of cuisine, a saviour for those who don't abhor the idea of cruising in principal, but fear being stuck in a culinary wasteland, surrounded by bain-maries and buffet connoisseurs.
Frenchman Jacques Pépin, Oceania's executive culinary director, has an eponymous restaurant on both ships and leads cooking demonstrations for guests. At the Culinary Center guests can attempt to master a few dishes themselves - tarte Tatin while sailing past France, paella as they float around Spain, and pizza and pasta as they set a course for Italy.
I wouldn't describe myself as an adventurous traveller. Keen, yes; esoteric in my travel tastes, no, not really. So, on paper, there's nothing in this itinerary that should cause any great alarm, other than relinquishing a fair degree of control. That and confined spaces - confined spaces shared with a not insubstantial number of Americans.
But exhalation is possible once I get past the performance aspect of being clapped up the gangway by the waiting crew and clock our compact but very functional stateroom with its subtle nautical theme, generous teak balcony and marble bathroom with bath - bless.
Later that evening we head for the stairwell, and it's soon apparent that we've hit rush hour. Lift after lift opens to reveal a crush of (older) bodies - the women often armed with bedazzled clutch bags and heaven-reaching blow-dries; the men in suits, some with walking canes - heading for the early sittings upstairs in Toscana (Marina's Italian trattoria) or the Grand Dining Room, the traditional main restaurant where the linen tablecloths are always starched, the waitstaff are always in tuxedos and the sommeliers are always… Ukrainian. The stairs, it seems, are under no threat of overuse.
Then there's the counterbalance: the well-patronised Canyon Ranch Spa Club, where Wallis Simpson-approved types (rich and thin) make a valiant effort at recapturing their glory days. And, in truth, the fitness classes come in handy following a few unscheduled days of sea snacking on Reuben sandwiches and Packy burgers - braised short rib with blue cheese - from Waves, and one particularly memorable lunch ashore at Mugaritz, in the hills above San Sebastián.
Marina drops anchor at Saint-Jean-de-Luz - a quaint port town on the border of France and Spain. Anxious moments ensue when we struggle to find a taxi and the possibility of missing out on our table at the world's third best restaurant looms large.
Hours later, we're drunk on the thrill of Andoni Aduriz's precise approach to food, the chickpea beer served to us as apéritif, the bottles of Cava, Richebourg and Vega Sicilia consumed over lunch, and the adrenalin rush of almost missing our launch back to the ship on account of all of the above.
Somehow we manage to front for dinner in the opium den-inspired Red Ginger, where the menu is a rather predictable assortment of dishes from Thailand, Japan, China and Malaysia. From the sublime to the ridiculous. And so the next morning I find myself pedalling against the tide - or so it seems - in an indoor cycling class in the Marina gym. Nothing is more disconcerting than riding a stationary bike on a moving ship. With a ferocious hangover.
Jacques Pépin resides in one of Marina's sprawling Vista suites (topped only by Ralph Lauren's handiwork in the three Owner's suites). He tells me that "people's interest in food has grown exponentially" since he first cruised 30 years ago, "so now that is also reflected on a cruise ship". Pépin believes the US line has done well at debunking some of the preconceptions of cruise-ship food: "Tonight we are doing a patio dinner - last year we did it in Bordeaux and we went to the market and bought three types of cep and we cooked for 20 people on the patio. It's fine to do that for 20 people, but it's not like you can go to the market and ask for 600 pounds of fish. You have to be very organised with things like the beef. Along the way we do get vegetables, but it really depends on where the ship goes and the suppliers.''
Where the ship goes can also make a significant difference to what you drink on holidays. Oceania has a surprising but very welcome policy that allows guests to BYO wine to all of its restaurants for a $25 corkage fee. So you can snap up a bottle of Bordeaux from Lynch-Bages in Bordeaux and enjoy it with a 900gm 28-day dry-aged prime rib served King's Cut (bone in) or Queen's Cut (boneless) in the Polo Grill. Or you can find something perfect to have with your moules marinières in Pépin's own restaurant, Jacques.
Plus, the BYO-ing avoids the slightly awkward pall cast over dining proceedings by Marina's lack of an all-inclusive drinks policy. Which is a pity, because the Grand Bar, with its nightly string-quartet performance by Russian musicians decked out in matching pink taffeta, is worth taking in over an Old Fashioned.
Just don't make any new friends if you want to avoid the "Whose shout is it?" conversations. Or win big on the craps table at the casino and you can treat the entire deck.
Our sail continues seamlessly around the coast of Spain, and I gradually get to grips with the rhythm of life onboard. Each morning we fuel up on coffee from the New Zealander manning the machine at Baristas and then breakfast at one of the outdoor tables at the stern's Terrace Café before embarking on shore excursions that allow us to marvel at Frank Gehry's bulbously beautiful Guggenheim Museum in Bilbao; to touch on the shrine of Saint James in Santiago de Compostela; to stumble around the back streets of a searingly hot Seville in search of cerveza and shade. We return in the afternoon for gin and tonics on our teak verandahs, finger sandwiches and millefeuilles for high tea; magicians and Motown in the Marina Lounge; and Martinis at Martinis.
I never make it to the Artist Loft enrichment centre, nor do I belt out karaoke in Horizons. I don't avail myself of the weight vests on offer to make walking the fitness track that tiny bit more challenging, and I still find the main stairwell, fashioned from Lalique crystal, gaudy rather than grand.
And so now my cruising credit count is less than one, but more than zero. Is there a Diamond (status) in my future? You've got to start somewhere.