TOMORROW’S BOATING TODAY
With sleek lines that immediately announce its Greenline pedigree, the 58 Fly is a luxurious coastal cruiser, a high-tech hybrid pioneer, and a spacious long-range explorer. Below deck, it offers more room than many yachts in its class, and above, it promises a boating experience that balances comfort, performance, and economy in equal measure.
“Changes happen as time passes by,” Kermit the Frog once said. While we doubt he ever cruised a 58-foot semi-displacement yacht, the sentiment perfectly captures the philosophy behind
the Greenline 58 Fly: a vessel that embraces modern technology while charting a new course through the conventional motor yacht market.
The 58 Fly is a semi-custom, semi-displacement yacht that intentionally diverges from the high-speed chase that defines much of its competition. In a world where many 18-metre motor yachts boast top speeds of 30 knots plus, Greenline has chosen a different path. And it’s a path that pays dividends. After all, pushing offshore at 30+ knots is often uncomfortable and extremely fuel-thirsty. Since most yachts in this category are mostly used for coastal cruising, fuel tanks rarely exceed 2,220 litres, limiting both range and necessity for extreme speed.
FINDING A MIDDLE COURSE
Rather than aiming for the extremes, the 58 Fly occupies a thoughtful middle ground between slow, displacement-style trawlers and the jet-setters of the fast motor yacht world. It is designed to cruise comfortably at 15-20 knots in semi-displacement mode. However, for those considering long-range voyages, Greenline’s optional hybrid power system offers a remarkable solution that extends range far beyond conventional thinking.
By integrating an electric motor between the engines and transmission, coupled with a bank of Lithium-Polymer batteries, the 58 Fly Hybrid introduces a level of versatility unseen in this class. By alternating between diesel fuel and electricity, the yacht can extend its operational range in both practical and impressive ways.
GREENLINE’S HYBRID POWER
Greenline first embraced hybrid power roughly 15 years ago, and the company has since refined the system through six generations. While most builders have avoided hybrid technology for cost or complexity reasons, Greenline has pioneered its use with motor/ generators and high-capacity lithium batteries.
The yacht’s synchronous electric motors, each producing 25 kW at 60 V, operate with permanent magnets. In generator mode, each unit provides 14 kW. Standard Lithium-Polymer batteries have a 55 kWh capacity. For context, LiPo batteries utilise a polymer electrolyte instead of a liquid one, forming a highly conductive semisolid gel that delivers more specific energy per kilogram than other lithium battery types, ideal for applications where weight is a critical factor.
DIESEL POWER
Complimenting the electric system are standard Cummins QSM11 engines, rated at 715 hp at 2,500 RPM. These marinised units are EPA Tier 3 and IMO Tier II compliant and are known for their durability and longevity. Designed to operate under continuous heavy load, they give the 58 Fly the ability to cruise confidently, whether near shore or across extended passages.
GOING THE DISTANCE
The 58 Fly’s potential shines for long-range cruising. Whether it’s the 5,214-nm American Great Loop, the 6,083-nm around the Caribbean, an 8,690-nm Mediterranean circumnavigation, the 7,821-nm “Big Lap” around Australia, or exploring the Indonesian archipelago, the 58 Fly Hybrid is ideally suited for the adventurous boater seeking both economy and comfort.
DIESEL TEST – CUMMINS ENGINE
On test, with a 50% fuel load and five aboard, the 58 Fly achieved a top speed of 23.1 knots at 2,540 RPM. Semi-displacement hulls don’t plane, so there isn’t a single “best” cruising speed; fuel efficiency was largely linear across the spectrum:
2,000 RPM / 15.3 knots: 0.10 nm/L ~321 nm range (3,500 L, 10% reserve)
1,250 RPM / 9.3 knots: 0.20 nm/L ~628 nm range
1,000 RPM / 7.6 knots: 0.31 nm/L ~972 nm range
ELECTRIC TEST
Switching to electric-only revealed one of hybrid’s quirks: there’s no idle; the boat either moves or doesn’t.
400 RPM / 3.4 knots: ~38 nm range
500 RPM / 4.1 knots: ~22 nm range
600 RPM / 5.0 knots: ~12 nm range
Effectively, 600 RPM represents the practical top end under battery power, a balance of speed and endurance. Faster speeds would rapidly deplete energy reserves, rendering range moot.
COMBINING AND MAXIMISING THE RANGE
To maximise fuel efficiency, Greenline recommends a rhythm: cruise at 7.6 knots on diesel to charge batteries, then switch to 5 knots on battery power until near depletion, and repeat. With 3,150 litres of usable fuel (90% of the optional tank), the system can theoretically cover 1,727 nautical miles by alternating diesel and electric power. For context, diesel alone at 7.6 knots provides 972 nm; battery power alone extends 756 nm. These numbers assume attentive operation and are theoretical, but they highlight the strategic advantage of hybrid propulsion for long-range cruising.
ONBOARD WALK-THROUGH
Bow: The forward trunk cabin features a wide sun pad for three, ideal for decadent luxury at anchor. What sets the 58 Fly apart are the two aft-facing love seats port and starboard, providing unique forward-facing relaxation. Underneath is a spacious chain locker, housing a 50 kg galvanised anchor and 50 m of 12 mm chain, robust for long-range cruising.
Aft Deck: The aft deck is fully configurable.
On our test boat, two love seats sat perpendicular to the transom, which features a large safety-glass window to keep occupants aware of activity on the aft deck. Large bollards replace standard 250 mm cleats, allowing for heavier mooring lines to be handled efficiently.
Galley: Greenline has positioned the galley aft within the deckhouse, allowing both main dining and entertaining areas easy access. The U-shaped galley offers 1.14 m of space between counters, ample for two people to work side by side or back to back, a significant improvement over the “alley-galley” style standard in this class. A fold-down platform doubles as a bar or serving station.
Saloon: A highlight of the 58 Fly is its one-level deck design- not a single step from cockpit to helm. The salon is situated flush with the aft deck and galley, providing unobstructed sightlines and ample headroom. Low side-window sills afford excellent visibility without the need to raise the dining area, ensuring the interior feels both spacious and connected to the outside.
Lower Helm: The helm is thoughtfully laid out. Optional 19” SIMRAD MFDs provide vital system monitoring, while control sticks and bow/stern thrusters are reachable from the side deck. The starboard sliding door enables single-handed tie-up without extra aft-deck controls or remotes.
Accommodations: The 58 Fly offers a three-stateroom, three- ensuite-head layout, all surrounded by the vertical-grain rosewood and warm teak woodwork seen in the salon.
The master stateroom is reached by going aft and down three steps. The deck is built atop the boat’s floors and extends between the stringers, which are outboard and don’t get in the way. This design element provides the cabin with 1.93 m of headroom. The standard configurations of this cabin call for cabinets and drawers to port and starboard from the stringers outboard. The sofa to port is an option. The hull side windows are large, and each has an opening port on both sides of the cabin for fresh air. There are three insulated bulkheads between the master suite and the engine room, making it very quiet. This is unusual because not only does the 58 have the fuel tank directly behind the cabin’s aft bulkhead (a common practice), but it also has the utility room/crew cabin in between, which is the unusual aspect.
VIP Stateroom: Most motor yachts have a VIP in the bow, but because the Greenline 58 Fly has a rather blunt bow, and the beam is carried forward above the chines farther than most, there is
more room in the forward cabin. As a result, the island berth does not need to be tapered at the foot, which is often seen on boats in this class. There is more room to port and starboard of the island berth, making it easier to make up. Greenline has placed horizontal windows on the sides of the trunk cabin overhead, which let in lots of light and keep the cabin from feeling like a dark cave. With the sun cushion removed from the pad on the deck, light can also come in through the forward hatch.
The Guest Stateroom: All third cabins in this size motor yacht have a compromised width, and the Greenline 58 is no exception; however, it has actually performed better than many models. We measured the width of the inboard and outboard beds at 71cm and 66cm, respectively, with 30cm in between. What is unusual about the layout is that this stateroom has its own private head with a separate shower.
FLYBRIDGE
The flybridge extends approximately 7.6 m fore to aft. A hydraulic davit at the aft third accommodates the tender, keeping the swim platform free. Seating includes a port-side wrap-around banquette, a bench with a café table, and two forward-facing fixed benches on the bridge deck. The upper and lower helm layouts mirror each other, and a 5.6m carbon-fibre hardtop provides UV protection while maintaining a low centre of gravity.
SOLAR POWER
Three standard photovoltaic panels (1.230 kW/h) are mounted forward of the flybridge, with an optional seven-panel hardtop extension, bringing total power to 4.100 kW/h. This is sufficient to operate essential systems for days while the yacht is unattended, a wise choice for long-range cruisers.
It also makes for peaceful stays at anchor as regardless of whether you choose the Hybrid or standard Diesel, the Greenline collects and stores power from the sun. Enough to enjoy the onboard appliances without a noisy generator.
ENGINE ROOM
The engine room, accessible via a gas-assisted aft hatch, offers 1.80 m of headroom. Its uncluttered layout owes to the absence of a conventional diesel generator and the use of an optional 70,000 BTU reverse-cycle chiller. Electric Humphree interceptors provide stabilisation, eliminating the need for gyros or hydraulic fins.
DIESEL-ONLY OPTION
Owners may forgo hybrid power, saving around $300,000, with space available for 11–25 kW diesel generators. The advantages of solar power are maintained, but while more straightforward and more cost-effective, this option sacrifices the extended range benefits of hybrid propulsion.
OBSERVATIONS
Even without hybrid power, the Greenline 58 Fly excels. At 5.12 m beam, it is the widest in its comparison group, and only the second heaviest. Its three ensuite staterooms and 100% vinylester hull and deck set it apart from competitors. Vinylester construction, rare in this class due to cost, provides superior strength and resistance to water ingress.
THE GREEN OF GREENLINE
Greenline deserves credit for pioneering hybrid power in the motor yacht sector. Initially valued for quiet, low-speed cruising, hybrid technology now enables remarkable long-range economy when used strategically. Whether hybrid or diesel-only, the 58 Fly offers comfort, range, and versatility for the discerning cruiser, delivering an experience that blends adventure, sustainability, and the pure pleasure of being on the water.
SPECIFICATIONS
LOA 18.2m
Beam 5.1m
Dry Weight 30,000kg
Bridge Clearance 5.96m
Fuel Capacity 3,500 L
Water Capacity 600 L
PERFORMANCE DATA
RPM KPH KNOTS LPH
600 8.4 4.5 8.3
1000 14.2 7.6 24.6
1500 20 10.7 71.9
2000 28.5 15.3 149.9
2540 42.8 23.1 290
