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When you get on a brand-new trawler owned by Theo Koop, the boss of one of the world’s leading vendors of yacht stabilizers, you can expect it will remain upright. RotorSwing has supplied stabilizers to many of the world’s largest superyachts, as well as to the U.S. Navy, so he must rank highly as an expert in stabilization.

As you would expect, the new Altena 50 was fitted with the latest product from Koop’s innovative company, and he was so proud to demonstrate its zero-speed capabilities that he had rigged up the system to show off its functionality even though we were alongside a berth in calm waters. But by changing a pair of wires, the owner was able to make the stabilizers operate in reverse, rolling the boat when it was steady alongside and becoming steady when the stabilizers were stopped. It may sound strange but this was the only way to demonstrate these remarkable new stabilizers on a day that was devoid of waves.

Centerline helm with a neatly laid-out dash featuring twin Raymarine MFDs.

Centerline helm with a neatly laid-out dash featuring twin Raymarine MFDs.

Unlike previous versions of the product, this latest version of RotorSwing’s innovative system can operate when the yacht is stopped. RotorSwing stabilizers previously relied on boat movement, generating a righting moment with a rotating cylinder that protrudes from the side of the hull and uses the Magnus effect to create an upward or downard thrust to counter the rolling of the hull. This new version, however, can stabilize the boat at anchor by simply moving the stabilizing cylinder through the water to generate thrust, rather than relying on the movement of the whole boat.

The new RotorSwing stabilizers work equally well when underway as we found when trying to cope with the considerable wash of the mighty inland waterway barges that traverse the Dutch canals. And while the Altena 50 has a multi-chine steel hull that is close to a rounded-bilge in shape (which would provide good stability on its own), every little bit helps when it comes to a smooth and comfortable passage.

The Altena 50 features twin boarding steps from the swim platform, safe bulwark heights, large hawse pipes, and a design that blends traditional accents within a contemporary package.

The Altena 50 features twin boarding steps from the swim platform, safe bulwark heights, large hawse pipes, and a design that blends traditional accents within a contemporary package.

With the hull design of the 50, Altena has struck a good balance between comfort at sea and interior capacity. Many designs puff out the bow sections to create as much interior space as possible, which can lead to excessive pitching in a seaway. But on the Altena, the bow sections are relatively fine and a certain amount of flare has been introduced in the topsides, which should make this a dry ride in head seas. You may not get quite the large double bed comfort in the bow cabin found in some competing yachts, but the Dutch are nothing if not practical and many favor V-berths in the bow. Bear in mind, however, that what one owner finds is a good solution, another might want to change. And every Altena is custom as far as the interior is concerned—within the limits of the structure, of course.

The more I see of Dutch steel yachts, the more impressed I am. Not only can these masters persuade the steel to bend into beautiful curves, but they can give it a finish that any fiberglass builder would be proud of. The beautiful paint jobs on yachts like the Altena 50 not only offer a lifetime of protection but also have the deep luster of paint that can never be achieved with the gel coat surface of composites.

Sizeable L-shape galley and stowage options before the raised pilothouse.

Sizeable L-shape galley and stowage options before the raised pilothouse.

The yacht tested was Altena’s raised pilothouse version of the 50, which offers a spacious wheelhouse with a panoramic dash dominated by a pair of large Raymarine screens. The view aft is blocked by lockers, but the current owner has overcome this by fitting a camera that displays a clear view on a dash LCD of what is coming up aft of the ship. This should be important for everyone at sea but it is particularly important on the Dutch canals where huge barges travel at 12 knots and demand right of way. In a yacht the size of the Altena, you don’t argue with them!

The reverse-angle pilothouse windows offer a clear view and wipers are fitted to the front and side windows to maintain visibility. These windows are double glazed to both reduce sound and minimize heat loss. At the rear of the pilothouse is a settee with an innovative sliding table that can be moved to allow easy access. On each side of the pilothouse, a watertight door leads to the wide side decks that make it easy to move around this yacht.

Beamy saloon with plenty of seating and stowage.

Beamy saloon with plenty of seating and stowage.

The saloon is at a lower level with the comprehensive galley at its forward end so serving is close to the recipients at the saloon table. It all looks comfortable and cozy with a rising TV coming out of the lockers opposite the U-shape settee. While I generally like to see fiddles around the stove in a galley, perhaps these owners have enough faith in the stabilizers to keep the boat steady while cooking. Overall, the galley was well designed, with the exception of one fridge door that opens aft. After a lively passage pitching into a head sea, the fridge contents will tend to slide aft and congregate behind the door, releasing an avalanche of food and containers when the door is opened.

Easy stairs down from the pilothouse give access to the accommodations below, including a comfortable two-berth cabin and a single in addition to the V-berth in the bow. The forward master cabin has direct access to its own bathroom while the others share facilities. But again, owners can choose from a wide range of cabin layouts.

Detail of the bamboo saloon table.

Detail of the bamboo saloon table.

A unique feature throughout this yacht is the use of bamboo as the wood both for the paneling and furniture, and even on the decks. Bamboo is an environmentally friendly choice but also a practical one as the finish looks good and supposedly does not change color with age.

Outside, the cockpit offers a comfortable sitting out or dining area with its transom settee and teak table. I am a bit concerned about the mooring arrangements with their beautifully crafted stainless steel fairleads inset into the bulwark. They have quite sharp edges on their outboard lower edge, which could chafe through a rope quite quickly if there were any movement in the boat when alongside. It’s a common fault I have seen on many boats and shows what can happen when style takes over from seamanship. A more practical approach is seen with the fender stowage, which is in easy-access lockers on the coachroof.

Second stateroom doesn’t carry much headroom, but both twin bunks are comfortable and adequate for guests or little ones

Second stateroom doesn’t carry much headroom, but both twin bunks are comfortable and adequate for guests or little ones

Hidden away in the bowels of the Altena is an advanced propulsion system that combines a single diesel engine with a pair of electric sail drives to offer a variety of propulsion options. The twin John Deere 130-horsepower diesels drive the 50 along at a useful 10 knots with economical cruising at 7 knots. Switch off the diesels and the two Sonic sail drives with folding propellers powered by electric motors will give a speed of between 2 and 3 knots, which is enough if you just want to idle along, enter sensitive areas, or fish. There is not enough electric power to offer a significant boost if you use electric and diesel power in tandem, though. The electric drives do offer a get-home possibility, however, with the generator supplying the power to keep the batteries topped up, and a pair of large battery banks give a useful endurance under battery power alone.

I would question whether the electric drives have enough power for harbor maneuvering, but one reason for choosing these electric power units is that they have the same electric motor as is employed to power the bow and stern thrusters. These thrusters, combined with the diesel engine and a large rudder, provide all the maneuverability you could want, and they can all be combined in a compact handheld unit that allows you to control the yacht from anywhere on board remotely. While this does offer convenience for single-handed sailing, the owner is nervous about using this portable controller as it puts quite a bit of trust in the electronics performing when you need them.

A cockpit ladder that is arguably too steep provides access to a flybridge where you gain panoramic views of the horizon combined with a good social area. The mast, which carries the entire antenna and the masthead navigation light, can be lowered electrically to reduce air draft. The tender stows up here as well with a small crane for launch and recovery, but an alternative stowage for the tender is on the narrow swim platform.

The Altena 50 is a high-quality trawler yacht that demonstrates that steel construction can be a viable alternative to more common composites. All the interior surfaces behind the paneling are sprayed with thick sound-deadening foam, which means that sound levels are remarkably low and all you hear of the engine is a low rumble that is reassuring rather than irritating. The yacht tested was the first in the series and, as the builder pointed out, its production was rushed to get it to a boat show and it is now heading back to the yard for completion. With a powerful profile, the attractive Altena 50 makes a great addition to the trawler yacht market. 









36.5 tons

Fuel Capacity:

760 usg

Water Capacity:

263 usg


Twin John Deere 6068 DFM 130-hp diesels


Shafts and Propellers




Altena Yachting (