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SWATH technology lies behind Abeking & Rasmussen first cruise design

Wed 17 May 2017 by Rebecca Moore

SWATH technology lies behind Abeking & Rasmussen first cruise design
Abeking & Rasmussen’s Luxury Cruising vessel concept is only the second cruise ship design ever to use small waterplane area twin hull – SWATH – technology

Technology that slashes motion is key to the entry of German shipyard Abeking & Rasmussen into the luxury expedition cruise sector

German shipbuilder Abeking & Rasmussen (A&R) has entered the luxury expedition cruise ship market with a design using SWATH technology that boosts passenger comfort by reducing the motion of the vessel.

Indeed, it is this small waterplane area twin hull – SWATH – technology that is the stand-out feature of the cruise design and the shipyard’s selling point for entering the luxury expedition cruise sector.

It has launched Luxury Cruising, a 95m boutique ship concept for 166 passengers in 83 suites with private balconies, some of which have their own forward facing secluded terraces. The design is based on what the shipyard calls SWATH@A&R technology – it has taken the SWATH technology concept and developed it further. The typical shape of the design radically minimises motion on board, to a quarter of the level of conventional ships.

A&R naval architect and sales director of special vessels Nils Olschner explained the SWATH concept to Passenger Ship Technology. “The buoyancy – the volume that is carrying the vessel structure – is taken below the waterline, so it is removed from the energy and not excited by waves. If it is not excited, then it does not move. This means that it offers the comfort of a much bigger vessel, of 200m or 250m in length.”

“We are growing. The products we are building are growing. The feeling was that we had reached a stage at which we were able to build larger vessels as well.” Nils Olschner (Abeking & Rasmussen) on why the yard has entered the cruise market

 

While this technology has been around since the 1930s, Mr Olschner said: “We have taken the technology to a new level. No other shipyard has built so many SWATH vessels of so many different sizes.” The yard has built and has on its orderbook a total of 26 vessels in five different sizes with SWATH hulls. It has been applying this technology to hulls since 1999, and has patented some parts of it. One example is the shape of the struts – the arrangement of the connecting parts between the lower hulls and the actual platform of the vessel.

Mr Olschner compared the design to that of a catamaran – but with one crucial difference. “In a catamaran there are two hulls, but the volume of the ship is at the surface of the water.” With a SWATH vessel there are two hulls, too, but the volume is located below the water level.

With the exception of Radisson Diamond, a SWATH cruise ship built for Diamond Cruise and launched in 1991, this technology is new to the cruise sector.

The SWATH technology is the unique feature of A&R’s vessel design. Everything else in the vessel is conventional. The propulsion plant can be diesel-direct or diesel-electric – whatever the application requires. The engines are down in the hulls, far away from the accommodation where noise would be a problem.

A&R decided to break into the cruise sector last year. The shipyard has been in existence since 1907 and is a family-run business. The current chief executive is the great grandson of the founder. Starting with a 3m dinghy, it has built a wide range of vessels, spanning sailing boats, motor yachts and car ferries, and its orderbook now amounts to 6,506 vessels. Recently its main focus has been on the private motor yacht sector.

Explaining why the shipyard has decided to step into the cruise ship sector, Mr Olschner said: “We specialise in niche markets, and our observation is that when standard passenger vessels are growing in capacity, there must be a niche market for smaller, more individual vessels.”

A&R identified the luxury expedition cruise sector as a growing, niche market that it could target. This aim coincided with a surge in growth within the yard.

“We are growing. The products we are building are growing. The feeling was that we had reached a stage at which we were able to build larger vessels as well.”

Indeed, the yard has recently been building some of the largest motor yachts that it has ever undertaken, constructing vessels of up to 100m in length.

In the last quarter of 2016, the shipyard decided to prepare to enter the cruise ship market. “We saw that we were on the right path, but we had to change the way we were working at the shipyard. Before, we were a little shipyard building smaller vessels, with all employees running around doing all jobs,” said Mr Olschner. The company realised that when it started building bigger vessels there would be more challenges and that the yard needed to modify the way it was working.

Mr Olschner said: “We have introduced methods which can best be compared with assembly lines in the automotive industry. For example, the actual construction work is completely detached from the logistics part, enabling us to react very fast on the spot to improve the production flow.”

This means that the shipyard is “much more capable than before.” And it is ready to enter the luxury cruise sector.

Presenting a market-ready ship design is not something that the shipyard normally does. It usually develops vessels with clients, a method that it prefers. But A&R decided to present SWATH technology in a full design in order to enter the cruise market. Mr Olschner explained: “It is all ready. We have done full calculations and full drawings. If someone signs today we could start building tomorrow.”

A&R launched its concept cruise ship earlier this year at Seatrade Cruise Global in Fort Lauderdale, USA. Mr Olschner said that the company was “amazed” at the reaction from the industry there to the design. “We made good contacts and the next stage is to work on a real project, with potential customers,” he commented.

The SWATH design is the main focus for A&R when it comes to entering the cruise market. But there are two other concepts that it wants to bring to the market, too. “There is a lot of interest in private yachts that have been re-engineered into high level cruise ships.”

The shipyard has therefore prepared a conventional monohull cruise yacht concept based on a motor yacht design. This could be built to any specification, but the model that A&R introduced at Seatrade Cruise Global was a 112m ship for 48 passengers and a crew of 49, built to the same standard as a private megayacht.

The cruise tender market is another area that the shipyard is keen to enter. A&R has built 18 pilot tenders to serve large cargo ships on high seas. Despite the rough seas in which these vessels operate, there has not been a single accident since the yard launched its first tender in 1999.

Mr Olschner said: “It is really safe to carry out boarding at sea with these vessels. The big cruise companies use these tenders when cruise vessels are lying at anchor.” A&R has prepared a concept design for the cruise ship sector.

Despite its interest in these two areas, the main thrust of A&R’s efforts lies with its SWATH technology.

Mr Olschner summed up the main benefit for a luxury expedition cruise ship operator of using SWATH. “You can have the privacy of a small vessel with the seakeeping capabilities of a much bigger cruise ship.”