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It’s a question as old as river cruising itself: are there too many ships sailing European waterways?

It has again become a talking point as lines unveil their latest gleaming tech-filled vessels for the start of the season in 2019 – and some admit they are finding it unusually tough to fill some cabins this year.

So some are making some pretty compelling offers to stimulate the season.

Most owners are sure it is a temporary blip. Others are unusually forthright about what they see as a change.

Travel Weekly, an authoritative trade publication, quoted Brett Tollman, CEO of the Travel Corporation, parent of the Uniworld and U river cruise brands, as blaming oversupply for the discounting.

“If you don’t believe there’s too much capacity, why are we seeing the two-for-one offers or 75% off?” he was quoted as saying this month. “What good is that for any company or for the industry?”

According to Travel Weekly, agents are also concerned about oversupply. Others blame last year’s low water levels and a hangover effect on bookings.

Avalon Waterways, which launched a new panorama ship on April 7, reported a strong start to the year.  Then came a slowdown.

“There was a little slowdown … when the [U.S.] government shutdown happened, the stock market took a little hit, and I think also on the downside of our situation last year was the water levels in Europe,” Pamela Hoffee, managing director of Avalon Waterways, said.

“What I hear from my colleagues is that that was across the board, and not only in river cruising but all kinds of premium-brand product.”

Rudi Schreiner, president and co-founder of AmaWaterways, was quoted in the Travel Weekly report as saying: “We were strong up until October, then it slowed down…but overall we are doing good.”

The season has seen a bullish start.

Award-winning Viking, with the biggest fleet on the waterways, launched seven new river ships simultaneously this month.

British newcomer Riviera Travel launched two new ships this month – the 169-passenger William Wordsworth and 132-guest George Eliot, bringing its fleet to 13 vessels.

Uniworld’s newest Super Ship, Bon Voyage, has just completed its first cruises in France’s Bordeaux wine region.

AmaWaterways launched the biggest river ship yet, AmaMagna. The ship is twice as wide as the usual European river boat, yet has a capacity of only 196 passengers. It features larger suites with full balconies, multiple dining venues, a water activities platform with a Sundowner boat for excursions, a large wellness studio, massage rooms and a pop-up Sun Deck bar.

There is no doubt interest in river cruising is growing. And the amazing work being done by many lines to attract younger, fitter and more active cruisers is changing the way the world views this type of holiday.

Uniworld’s bold move in launching a fresh millennial brand, U; Avalon’s active holidays; Viking’s new itineraries and new low-cost entrants like Teeming River Cruises and Riviera Travel have peaked the interest of new generations with solo offerings.

And Crystal’s entry, with amazing luxury ships and service, has also caused ripples among ocean cruisers.

Other signs which could explain the changes on traditional Rhine and Danube routes are in the growth of Portugal, France and even Asia as strong new destinations – attracting the mighty European waterways traditional sailors.

As this year’s season gets underway, every line will be polishing its offering, putting out its best offers, and watching to see if 2019 is a watershed year – or just another milestone in the extraordinary growth of a great industry.