Stem 50: A new aluminium yacht from Italy with impressive design details put to the test
Jochen Rieker
· 07.08.2026
Twenty years ago, many industry experts predicted a severe wave of consolidation in the yacht market. Small manufacturers would disappear, they said. Some have indeed gone under, such as Etap, Finngulf and, most recently, Elan. Yet there are now more boatbuilders in Europe than ever before. Most astonishing of all is the growth in the niche market for aluminium boats suitable for long-distance cruising, a sector that also appeared to be under threat. However, ever since two former McKinsey consultants shook up the segment in 2003 with Allures, the range of suppliers and designs has simply exploded.
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Alongside typical explorer yachts, there are now round-bow designs such as the SeaScow 33, mass-produced aluminium catamarans such as the Garcia ExploCat 52, and high-performance boats such as the BM 53 or the Pure 42 from Germany. And since last autumn, the Stem 50 has been available. It is the latest addition to the range, built from seawater-resistant light alloy – a Mediterranean-style long-distance yacht packed with practical innovations and featuring a substantially first-class finish.
Stem Marine has its roots in government and professional boatbuilding
In fact, it comes from a boat-building company with an excellent track record. For 40 years, Stem Marine in Medesano, near Parma, has been producing rescue, patrol and fire-fighting boats to the highest industrial standards. With a workforce of 85, the Italian company also develops evacuation systems and shock-absorbing helmsman’s seats. They have now applied their craftsmanship for the first time to a 15-metre sailing yacht capable of taking you anywhere. A yacht in which “every detail has been designed and crafted with the utmost care and precision”, as Managing Director Michele Corradi emphasises.
The design is the work of Nicolas Purnu, a French naval architect who previously worked for the Marc Lombard Design Group. Development took three years, culminating in the launch at the end of last summer. The thoroughness of the approach is evident throughout: from the hermetically sealed stern section to the meticulously laid on-board electrical system, the Stem 50 takes nothing lightly.
A wealth of practical solutions with real-world benefits
Their dual autopilot configuration, for example, complies with the Imoca standard: it is fully redundant, meaning that you can switch from the starboard unit to the port unit with just a single turn of the control knob on the switch panel.
The forward sail storage compartment isn’t just a deep, large hole – it has shelves that are welded in such a way that they serve as a ladder whilst also helping to neatly stow fenders, ropes and the rolled-up Code Zero.
The storage compartments in the saloon are also unrivalled. They are made from milled, machine-bent aluminium sheets that are welded together to form trays. Fitted with hydraulically damped hinges, they can be opened downwards without anything falling out. Each of these eight storage boxes can hold a load of up to 20 kilograms.
The hull lines also differ from those of most competitors. The side walls in the foredeck, which are chamfered towards the deck, give the boat a sporty appearance, further emphasised by the white paintwork, which provides a lovely contrast to the otherwise bare aluminium, polished to a crescent-shaped pattern. When viewed from the front or the side whilst under sail, the Stem 50 could easily be mistaken for a performance cruiser. At the stern, however, the hull looks very imposing with its almost vertical transom and the large equipment rack protruding above the deck.
Plenty of features in the cockpit, though not all of them are impressive
Whilst build number one is fitted with all the optional extras available for the cockpit layout, including a fixed hardtop, the Stem 50 in its standard configuration has only a Targa bar at the companionway to which the traveller is attached. This gives it a lighter, more elegant and less functional character.
However, without the hardtop, you miss out on another unique feature: fully retractable, rigid sprayhood windows that can be opened and closed at the touch of a button. This does, however, come at a price: the rigid bimini costs 63,000 euros, whilst the servo-controlled polycarbonate windows add a further 16,000 euros. In the heat of summer, though, you’ll hardly want to do without these options, despite the hefty extra cost.
The cockpit itself is spacious enough for six to eight people. The benches are a generous 2.06 metres long and are separated by a sturdy aluminium table frame with fold-out side wings, complemented by numerous storage compartments. The backrests are almost vertical and are not particularly comfortable on long voyages. However, they are high enough to provide a sense of security. Two electric Antal winches next to the companionway make it easy to hoist and trim the sails. They are mounted lower than the cabin roof, which makes them pleasant to operate. However, this means that the halyards and stretchers must run at a 45-degree angle downwards towards the stoppers and then be redirected by a further 45 degrees through guide eyes onto the winches – an arrangement that increases friction and wear.
Unlike their push-button-operated counterparts, the main winches are operated manually as standard. They are positioned within the two helm stations, which makes cranking them safer and more ergonomic than if they were mounted on the coamings. However, the 90-degree deflection into the cockpit significantly increases the sheet loads, particularly with the large genoa. Electric winches are therefore highly recommended.
The layout is generally designed for sailing with a small crew; when all the winches are manned, space becomes a bit tight, particularly around the steering wheels. Visibility to the front is good. However, as the hardtop blocks the view upwards, you have to lean out of the cockpit to check the position of the mainsail or the traveller. Getting from the cockpit up onto the deck is also a bit of a faff. There are welded steps next to the helm stations, which are intended to make the climb easier. When wet, however, they are too narrow to ensure a safe passage.
High structural strength and a special keel design
Sturdiness is the top priority on the Stem. Frames spaced 75 centimetres apart – and as close as 35 centimetres in the area around the keel box – provide enormous strength. Even in heavy swell and gusts of up to 30 knots, the Stem showed no signs of weakness during testing.
Watertight crash boxes in the bow and stern further enhance the reliability of the design, as do the keel and rudder mountings. Whilst many aluminium explorer boats have a variable draught, Stem opted for a fixed keel, “because it offers much better efficiency and is maintenance-free”, as Michele Corradi points out.
The design is unique: the upper part of the 735-kilogram fin, which is precision-machined from a solid block of aluminium, fits deeply into the keel box with a positive fit; it is bolted through both horizontally and vertically, ensuring a wide distribution of forces. At the other end, the fin carries a 3.4-tonne, torpedo-shaped lead ballast, which ensures a low centre of gravity whilst keeping the overall displacement within limits. However, one must accept a draught of 2.40 metres. On request, however, the shipyard also offers a telescopic keel as an option.
Hence the twin-rudder system, which is made from Jefa components and offers plenty of grip and feel, whilst operating smoothly. The system is easily accessible from both the aft cabins and the storage compartment. It offers full redundancy. If one rudder becomes blocked, simply remove the aluminium push rod between the quadrants.
Part 2 shows how the Stem 50 performs in rough seas and winds of up to 30 knots, and what the boat is like below deck.
The Stem 50 in detail
Technical specifications of the Stem 50
- Designer: Nicolas Purnu
- CE design category: A
- Fuselage length: 15.00 m
- Total length: 16.06 m
- Waterline length: 14.34 m
- Width: 4.42 m
- Draught/alternatively: 2.40 m
- Mast height above water level: 21.80 m
- Theoretical fuselage speed: 9.2 knots
- Weight: 15.0 t
- Ballast/proportion: 4.1 t/28 %
- Mainsail: 67.6 m²
- Furling genoa (107 %): 72.9 m²
- Engine (Yanmar): 59 kW/80 PS
- Fuel tank: 350 litres
- Fresh water tanks (2): 620 litres
- Sewage tanks: 120 l
Hull and deck construction
Fully welded aluminium construction with three watertight bulkheads: two in the fore section, one aft.
Electronics
Although the extensive standard specification includes an on-board computer and a flat-screen monitor in the owner’s cabin, it does not include the navigation electronics. A B&G package, including an autopilot, radio and AIS, costs 17,260 euros.
A new shipyard, a new concept, lots of original ideas: would you trust a newcomer yacht like this for a long voyage? Let us know in the comments.
Jochen Rieker
Herausgeber YACHT