The Norwegian Jewel, latest launch in the Norwegian Cruise Line fleet, is a massive  enterprise in mobile holidaymaking. Imagine a vast resort hotel, with swimming pools, theatre, casino, ten restaurants, children's clubs, tennis courts and jogging tracks, detaching itself from the shore and floating gracefully off across the beautiful blue seas.

This is not cruising as caricatured in the Carry On films. There may be tea dances - the ship is large enough to accommodate anything - but the Jewel is firmly aimed at the family market. The music in the pool area is disco loud, the colors are dazzling, the entertainment non-stop.

And the ship is truly huge. On boarding for her inaugural weekend voyage from Dover to Amsterdam, we took a lift from the echoing lobby to the eleventh floor, where a corridor carpeted with neon bright fish disappeared into the distance. From the dizzying height of our balcony, we peered down at tiny security launches buzzing around the harbor.

As we left Amsterdam and powered down its great canal to the sea, tiny people miles below us interrupted their evening strolls to stand and stare. We might have imagined it, but from the top deck it looked as if their mouths were hanging open.

Our children, 12 and 13, thought they were in heaven. Free rein to explore miles of deck, a variety theatre, basketball court, their own teenage club, with games room and discos till 1am, fast food at every turn, a no cash economy. We scarcely saw them once the ship had sailed, and they rolled back to our cabin long after we'd exhausted the evening's entertainments and subsided in front of a video.

So what's to do on board for grown ups? Eat, seems to be the answer. Is it the sea air? The all-in catering? The abundance of eateries? What makes a cruise passenger, who on dry land passes the hours between breakfast and supper quite happily on a cheese sandwich and a few cuppas, start checking his watch for the next meal while the last has scarcely passed the plimsoll line?

The selling point of the Norwegian cruise lines is "freestyle dining". Not for these ships the formal meal times, with James Bond white DJs and umbrage over invitations to the captain's table. On the Norwegian Jewel you can choose to eat anywhere from a bright and cheerful general cafeteria to an intimate French brasserie done out in nautical Toulouse Lautrecerie. One word of caution; while most meals are included in the holiday's price, some of the restaurants carry a fairly hefty service charge, and the wine list can be pricey.

And you can eat all day. When we boarded at 4pm, tables around the pool were already heaving, with families tucking into trays of fry-ups, chips, sauce, the lot. The ship can carry 2,000 passengers, but apparently expects 3,000 main supper courses to be consumed every evening.

Not too long on this regime, and there's nothing for it but to repair to the Bora Bora health spa, where the overcarbed can indulge in a generous array of treatments and therapies before heading back to the blowout zone. Of course, while the food is included in your fare, the treatments are not; they've got to make their money somewhere.

If pumping iron or being pumped by iron-muscled masseurs is not your idea of fun, there is plenty of gentle exercise to be had in exploring the ship, even if you don't take to the jogging track. The library didn't look very busy on our voyage, but the casino was rattling, and the pool and hot tubs were bobbing.