Greenline 58 Fly Hybrid (2024-)

Brief Summary

With modern lines that are distinctively Greenline's, the 58 Fly is at once a comfortable coastal cruising yacht offering high-tech hybrid equipment, more room below than many boats in class, and the promise of long-distance cruising at a remarkably low cost. 

Test Results

Specifications

Length Overall	59' 9" 18.2 m
Beam	16' 8" 5.1 m
Dry Weight	66,139 lbs. 30,000 kg
Tested Weight	69,700 lbs. 31,681 kg
Draft	3' 2" 1 m
Air Draft	19' 8" 5.99 m
Max Headroom	6' 4" 1.93 m
Bridge Clearance	19' 7" 5.96 m
Fuel Capacity	924 gal 3,500 L
Water Capacity	158 gal 600 L
Total Weight	69,700 lbs. 31,681 kg

Acceleration Times & Conditions

Props	31 x 27 x 5
Load	5 persons; 462 gal. fuel
Climate	73 deg.; 55% humid; wind 5 mph; calm seas

Engine Options

Tested Engine	2 x 715-hp Cummins QSM 11
Std. Power	2 x 715-hp Cummins QSM 11

Greenline 58 Fly - Future-Oriented, Here Today

Captain's Report by Capt. Ken Kreisler & Jeff Hammond

“Changes happen as time passes by,” said Kermit the Frog. While not a boater to our knowledge, he could not have framed what the Greenline 58 Fly is all about any better.

She is a semi-custom, semi-displacement yacht that takes a different course than most of the 58’ (18.2 m) motoryachts on the market and there are at least nine of them by our count. It’s a popular size for a reason – owner/operators feel comfortable at this size, as do insurance companies, and most builders manage to get three staterooms nestled inside.

The Overview

The most important defining factor of the 58 Fly is that Greenline has chosen not to pursue the holy grail of 30 or 40-knot top speed, as most of its competitors have. That decision set the Greenline 58 Fly, Hybrid and non-hybrid, apart. Its reason for doing that is going 30+ knots in a motoryacht offshore is often not comfortable and, in any case, literally burns through a ton of fuel.  Because most of these boats are used close to home, all but a couple of them have fuel tanks under 600 gallons (2,220 L) — it keeps the weight down and the boat owners aren’t going far, anyway.

Taking a Middle Course

On the other hand, Greenline has chosen to take a middle course between displacement trawlers that go at sailboat speeds and fast motoryachts that must notch at least 30 knots to be marketed. The Greenline 58 Fly is intended to be cruised at from 15 to 20 knots at semi-displacement speeds, when not going for distance. But, if an owner wants to cruise long-range, Greenline has the answer – and it is not just carrying more fuel.

Adding a motor/generator between the engine and the transmission, coupled with a bank of Lithium-Polymer batteries adds a new world of utility to the Greenline 58 Fly that currently no other boats in class have.  By alternating energy sources between diesel fuel and electricity, the boat’s range can be extended under some circumstances to a remarkable degree.

By building a hybrid motoryacht now, Greenline is helping to ensure that its yachts don’t become obsolete in 5 to 10 years when hybrid power is the rage.

 

 

 

Major Features

• Up to 3.6 kW of solar panels

• Conventional diesel or hybrid/electric drive

• Three ensuite staterooms 

• Hulls and decks infusion with 100% vinylester resin

• Low center of gravity for stability, safety, and comfort

• High bulwarks and rails all-around weather decks

• Rated CEB in Europe for seas up to 15’

• Amidships, full-beam compartment for many uses

• Standard bow thruster, trim tabs and MFD

• Highly customizable main deck and accommodations

• One, level main deck from the transom to the helm

• Carbon fiber hardtop

• Port U-shape galley

Notable Options

• Console on the flying bridge for amenities

• Captain/crew quarters

• Aft bridge deck awning

• Warping winches aft on both sides

• The office can replace starboard guest stateroom

• 2 x 1,000-hp Diesels Available

• 924 gallons (3,500 L) fuel capacity (This capacity is standard in the U.S.)

• 110kWh Lithium-Polymer Batteries

Greenline’s Hybrid Power System

Greenline first introduced hybrid power about 15 years ago.  Since then, other builders in class have eschewed it for one reason or another.  In the meantime, Greenline pioneered the use of motor/generators and high-capacity Lithium batteries on its yachts and the system we tested was the company’s sixth-generation system.

Greenline uses synchronous electric motors with permanent magnets, 60 V, producing 25 kW of power each, according to the company.  In generator mode, the unit produces 14 kW of power each.  The capacity in the boat’s standard Lithium-Polymer batteries is 55kWh.

A lithium-polymer battery (LiPo) is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyte. Highly conductive semisolid gel polymers form this electrolyte. These batteries provide higher specific energy than other lithium battery types. They are used in applications where weight is critical.

About the Diesel Engine

The standard Cummins QSM 11 engines are built for heavy-duty machinery where continuous load applications are common. The marinized version, which is rated at 715-hp at 2500 RPM, is EPA Tier 3 and IMO Tier II compliant. These engines are known for their long life, according to industry sources. Cummins says that the engine can be run continuously at 80% of 2500 RPM or at 2000 RPM.

Going for Max Range

Boaters considering making the 6,000-mile-long American Great Loop are generally interested in fuel economy because saving time is not the object, but saving money is.  So, anyone considering long-distance passages, such as the 7,000 miles around the Caribbean, circumnavigating 10,000 miles of the Med, taking the 9,000 miles “The Big Lap” around Australia or enjoying the remarkable islands of Indonesia, which could take a lifetime — all of these dream cruises are ideal candidates for a boat such as the Greenline 58 Fly Hybrid.

The Test with Diesel Power

We tested the 58 Fly in the Adriatic with 50% fuel load and five people aboard.

The top speed reached was 2540 RPM, at which point we hit 23.1 knots. Because this is a semi-displacement hull, she does not plane, per se, so there is no best cruising speed, and mpg readings were pretty much linear. At 2000 RPM, the boat averaged 15.3 knots, getting .39 nmpg for a range of 321 nmiles, with the 924 gal. (3,500 L) fuel capacity, with a 10% reserve. (See the metrics conversion on the chart above.)

At 9.3 knots (1250 RPM), which most boat owners consider a decent delivery speed, the boat got .76 nmpg for a range of 628 nmiles.

Going for distance and economy. Running the boat at 1000 RPM, which we consider sailboat or trawler speed, she went 7.6 knots and yielded 1.18 nautical miles per gallon and a range of 972 nmiles.

The Test with Electric Power

Once we were done with the diesel runs, we shut down the engines and went on battery power. The surprising thing about our speed runs under battery power was that there is no idle – she is either moving or not.  We started our runs at 400 RPM (3.4 Knots and a range of 38 nmiles), then 500 RPM (4.1 knots and a range of 22 nmiles), and then 600 RPM (5.0 knots and a range of 12 nmiles).  Our top-end under battery power was 600 RPM and 5 knots, which was a compromise between speed and battery life. She can go faster, but moving our tested weight of over 69,000 lbs. (31,363 kgs.) took so much energy that range would be meaningless.

Greenline Protocol for Max Range

Here's how to go for maximum fuel economy with our test boat: travel at 7.6 knots under diesel power until the batteries are fully charged, then go 5 knots under battery power until the batteries are nearly drained, then repeat. 

The big question we wanted to answer with our test of the Greenline 58 Fly Hybrid was how far she could go at displacement speeds using both diesel and battery power.

Greenline’s solution for both maximizing range and getting the most actual mechanical energy out of the usable 831 gal. of fuel available (924 gal. x 90%) in the 58 Fly’s optional (standard in the U.S.) fuel tank is to alternate between diesel and electrical power. With the diesel engines going 7.6 knots, the vessel can advance 15.2 nautical miles in the two hours it takes to fully charge the batteries.

When the engines are turned off, the batteries are turned on to release their energy to the motors, when run at 600 RPM, propel the boat at 5 knots for 12 miles, where the batteries are depleted, and again the diesel engine is turned on.  Repeat.

Because the engines burn 6.5 gallons of fuel an hour, exactly 13 gallons are burned every two hours to move the boat and charge the batteries. By dividing the 831 usable fuel capacity by 13 gal. per cycle, we see that there is enough fuel aboard to charge the batteries 63 times. That advances the boat 756 miles under battery power.  Under diesel power alone at 7.6 knots the boat can travel 972 miles under diesel power from a full tank (924 gal/3,500 L) of fuel.

Taken together, by alternating power sources, the Greenline 58 Fly can theoretically travel a total of 1,727 nautical miles.

What has been described above requires attentive operation, but it is theoretically possible to cover such distances. And, if that occurs, the operators will have succeeded in getting 2.08 nmiles per gallon from its engines (1,728 / 831 = 2.08). We hasten to emphasize that these are theoretical calculations. 

It is not advisable to run the battery pack to 0% charge, so every operator will have their own "switch-over" percent, say 8 to 10% of capacity.  That will reduce the battery-produced miles, say 10%, which translates into 75 nmiles fewer in battery power, for a total of 1,625 nmiles -- which is more of a realistic number.  And, 1.95 nmpg is still impressive. 

Boat Inspection

Bow

Greenline has placed a wide sun pad on its trunk cabin, forward, which can accommodate three people in decadent luxury while at anchor. Virtually all yachts have this feature, and a sun awning can be placed overhead—but what most boats in class don’t have are two aft-facing love seats port and starboard. Under, is access to the large chain locker.

Ground Tackle

Because the Greenline 58 is designed for real long-range cruising, its ground tackle and anchoring system will get a good workout, and we think it’s very much up to the job.  A 110-Lb. (50 kg.) galvanized anchor and 164’ (50 m) of ½” (12 mm) galvanized chain.  We think this is adequate in most anchoring situations, but some mariners might want to add another 100 feet.

A vertical Lewmar is standard and is certainly up to the job.  Buyers might consider a Lewmar horizontal windlass, which, in our experience, is less problematic because the chain comes up and down rather than up, around, and then down.

The most important aspect of the Greenline’s bow design is the size, shape and depth of the anchor locker. When plowing through heavy seas, say 5’ to 8’, for example, the bow can rise and fall rather quickly, and the result is much like a washing machine, but instead of tumbling clothing, it is thrashing the chain up and down and around.

Chain is notorious in such situations of becoming terribly tangled, and unlike line, the links can get locked into each other and snarled, and not pay out. For that reason, we like to stow large fenders on top of the chain to hold it in place.  If the chain does become a rat’s nest, the owner or crew must get down in the locker and tediously untangle it.

We have tested the size of the chain locker with our own 225-lb girth and found it easy to get into and out of.  Also important, and something we rarely see, is the bitter end of chain rode affixed by line to a pad eye within easy reach of the helm. Full marks to Greenline!

Aft Deck

The Greenline 58 Fly allows its owners to configure the furniture on the aft deck any way they want.  For example, on our test boat, the two love seats were placed perpendicular to the transom.  In the transom is a large safety glass window that allows those seated on the sofas to sea what’s happening on the aft deck without getting up.  It also provides sightlines to the sea for a more exciting view than looking forward at the cabin doors.

The long overhand of the boat deck above, which extends to the transom, allows owners to put up isinglass for three-season use. Vertical side panels on the side decks can block a chilly evening breeze for the guests on the aft deck.

As the image above shows, cutting a stairway into the aft bulkhead makes more useable deck space available without the intrusion of a full set of steps. Port and starboard are the large bollards that Greenline uses all over the boat instead of conventional cleats. We prefer these large mooring posts because they permit more large lines to be handled than is possible on standard 9” or 10” cleats.

Galley

The trend for the last ten years or so among motoryachts builders in this class has been to place the galley in the aft section of the deckhouse so that the two main dining and entertaining sections of the main deck are easy to service. This is the layout Greenline has chosen.

To port, the aft glass bulkhead opens, and a platform folds down to be used as a bar for guests on the aft deck or a sideboard when serving dinner al fresco

Once inside the boat and facing the U-shaped galley we quickly discover that it is different than most boats in class.  Many boats this size have what we call an “alley-galley” because there is a relatively narrow distance between the fore and aft counters.     

The important element setting the Greenline 58 apart from other boats is the 45” (1.14 m) wide deck space between the fore and aft counters, that can easily handle two people working side-by-side, or back-to-back.

Galley Appliance Policy. Since this is a semi-custom boat, and most owners prefer to specify their own galley appliances, except for the stand-up full-size refrigerator/freezer and induction cooktop, the appliances are all optional. Greenline offers a complete Miele package as an upgrade.  Our recommendation is for buyers to choose a brand that can be readily serviced in the home port of the boat, no matter what the brand.

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Salon

Perhaps the most important thing about the salon is that it is on the same level as the aft deck and galley.  Some vessels in class have a step-up from the galley to the main salon. That is done in order to provide adequate headroom below – something that Greenline has taken care of.

The Greenline 58’s one-level deck, and that includes where the dining banquette and table are located.  In some boats, this area is raised to give better visibility out the windows, but because the side window sills are low on the Greenline 58 Fly, that is not necessary.

The woods used on the bulkheads in the salon (and galley) of our test boat were Rosewood veneer with vertical grain. The cabinets and accent panels are warm or “golden” teak with a matt finish veneer.  The deck is ¾” (22 mm) thick light oak.   

The Lower Helm. Because owners all over the world have their own favorite brands of electronics, it leaves this equipment as optional.  The units seen here are 19” SIMRAD MFDs, at least one of which is obligatory with the H-Drive system. The double-screen unit seen here is recommended because all of the boat’s vital signs can be seen at once.

Note that both the control sticks and the bow and stern thrusters are located outboard of the wheel, and can be reached by the operator standing on the side deck when backing into a slip.  This design pretty much eliminates the need for aft deck controls or even a hand-held docking remote, both of which are costly. The sliding door to the starboard makes this possible, as well as aiding single-handed tie-up.

Living 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 3 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 gives the cabin its 6’4” (1.93 m) headroom. The A/C vents are to port and starboard in the overhead valance above the side windows. We prefer this design to the A/C vents directly over the head of the bed, having the cold air fall directly down on the occupants. Electrical and USB connectivity is standard on the port and starboard sides of the bed.

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 hullside windows are large and each have an opening port on both sides of the cabin for fresh air.

A Quiet Master Stateroom. There are three insulated bulkheads between the master suite and the engine room. This is unusual because not only does the 58 have the fuel tank directly behind the cabin’s aft bulkhead (which is a common practice), but it also has the utility room/crew cabin in between – which is the unusual part.   

VIP Stateroom.  Most motoryachts 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 we often see on boats in class. There is more room to port and starboard of the island berth, making it easier to make up. Electrical outlets and USB ports are on both sides of the bed in the shelving.

Greenline has placed horizontal windows in the sides of the trunk cabin overhead which lets lots of light into the cabin and keeps it from being a dark cave.  With the sun cushion removed from the pad on the deck, light also can come in through the forward hatch. A hanging locker and shelving for dry goods are located port and starboard.

Because this boat is semi-custom, owners can specify port and starboard berths, which add utility to the boat.  It also opens up the center of the boat, creating more room where it can be better utilized. Grandparents who want their children and their kids aboard should consider this option.

The Guest Stateroom. All third cabins in this size motoryacht have a compromised width of the cabin and the Greenline 58 is no exception – but it actually has done better than many models.  We measured 28” and 26” (71 and 66 cm) width of the inboard and outboard beds, respectively, with 12” (30 cm) in between.  What is unusual about the layout is that this stateroom has its own private head with a separate shower.

The overhead clearance in the entrance is 6’7” (2.02 m) and with the step down between the beds, is a full 7’ (2.13 m).  This is unusual for a third cabin. This space can be made into an office, or the inboard bed can be removed, and the outboard bed made wider to be a single-bed stateroom (think: crew or a nanny). It could also be turned into a huge walk-in closet and storage room, or any other number of things.

Flying Bridge

Accessed via a starboard stairway on the aft deck, the flying bridge measures about 25’ (7.6 m) fore and aft. The aft third of the deck, with the addition of a hydraulic davit, can be used as a boat deck for the yacht’s tender, eliminating the need to put it on the swim platform.  When the RIB is launched, the deck is available for lounge chairs for sunning, or other entertaining possibilities.

To port is a large table with a wrap-around banquette for al fresco lunch or dinner. Opposite is a bench seat suitable for 2-3 guests with a “café” table.  Forward are two fixed bench seats, port and starboard, that comprise the “bridge deck.” The operator and a companion can sit together, with two more observers sitting to port facing forward. The seats are fixed and not movable. Rail height around the deck is 30” (76 cm), which exceeds ABYC minimums.

The upper helm and lower helm are laid out pretty much the same, which is best practice. Here, the MFD screens are limited to 16” displays.  Most owners will specify an optional autopilot with remote, which makes piloting the vessel a relaxing exercise. The only changes we would make to this helm would be to place the compass on top of the MFD pod, and to add cupholders. They also make a good place to hold mobile phones.

Carbon Fiber Hardtop. This 18’ 4” (5.6 m) fore and aft hard top is optional, but we highly recommend it for its UV protection and comfort on sunny days, which it provides. It is well-designed and extended from forward of the helm to affect the seating, so everyone is protected from direct sun rays. Because it’s carbon fiber, it keeps the boat’s CG low. Two attractively designed pilasters hold the top, which is cantilevered forward and supported by two small stainless steel poles.

Solar Power

4 photovoltaic panels come standard and are mounted to the coachroof forward of the flying bridge.  They are rated at a total of 1340 Watts (1.34 kWh) of power. Seven more optional panels can be added to the carbon fiber hardtop.  The 11 panels can generate 3.6 kW of power, enough to operate the house’s essential battery draw for days, if not longer.

This is an option we recommend as it allows the boat’s electrical system’s critical components, such as refrigerators, pumps, appliances and even air conditioning for dehumidifying, to be operational when the boat’s on a mooring and unoccupied.

Engine Room

The Engine room is accessed via a large hatch (equipped with gas-assisted rams) in the aft deck. A removable ladder leads down between the engines. There is 5’10” (1.80 m) of overhead clearance.  This overhead height is an important consideration because boats with “crouching overhead clearance” are far less friendly and, by their very nature, discourage daily fluid and sea strainer checks.

The dimensions of the standard 6-cylinder in-line Cummins QSM 11 engines leave 23” (58 cm) between the engines and 10” and 9” (25 and 22 cm) of clearance, respectively, outboard port and starboard of the engines.  Most importantly, the main engine raw water intake through-hull ball valves are easily accessed on the centerline of the boat.  Their sea strainers are directly above, have plexiglass tops, and can be instantly inspected for grass or other debris.

Outboard, the mains have single Racor fuel filters, which can be easily accessed by climbing over the motor/generators and V-drive transmissions. We are used to seeing double filters on boats of this caliber, but like so many things on this boat, the owner can specify exactly what is wanted.

The engine room is remarkably uncluttered, and two things help contribute to that.  First, there is no conventional diesel generator, which would typically be 17 -20kW for this size boat.  Second, Greenline installs an optional 70,000 BTU reverse cycle chiller air conditioning system, instead of 4-5 individual condensers. For owners who will do a lot of boating in the tropics, a “tropical” system with 2x 50,000 BTU is available, and we recommend it.  Having three chillers instead of one provides important redundancy.

The absence of a gyro stabilizer or hydraulically-activated stabilizing fins, also aids the uncluttered look. Greenline uses a Humphree interceptor/fin stabilizer system which is electric.

Diesel Only

For those owners/operators who want to forgo the hybrid power solution, thus saving about $300,000 in initial cost, conventional diesel-powered generators can be installed. With the absence of the motor/generators, there is plenty of room for one or even two gen sets.  Greenline offers three generator options: 11kW, 17kW and 27kW.  We would specify the 17kW generator as the main one, possibly with the 11kW as a backup.

Eliminating the hybrid power simplifies the systems, keeps costs down, but of course, gives up the prodigious range possible.

Crew Cabin or Utility Room

One of the unusual design elements of the Greenline 58 Fly is the compartment directly under the galley cabin sole.  It has full standing headroom, is full bean with hull side portlights and measures about 31” (78 cm) fore and aft.  This compartment can serve all sorts of functions, much like an aft lazarette, but its location makes it particularly functional for purposes other than storage.

First, because it is directly under the galley, it is a handy place to put a washer and dryer.  It can also serve as a food pantry on long voyages. Most obviously, it can be a crew cabin with head. Because it is abaft the fuel tank, it also insulates the master cabin from any noise in the engine room.

Greenline App

Greenline has an app that monitors all of the boat vital signs 24/7 and allows the boat to be constantly monitored.  All the boat data is presented through a user-friendly interface. It is packed with features, easy to use, and comes with a customizable interface: just slide to set the detail level of your choice. Of course, it also lets you know at all times where the boat is, a good feature to have if the boat is chartered.

Options to Consider

• Sofa in Master Stateroom

• Ultra-Leather Upholstery

• Premium Electronics Package

• Wet Bar & appliances on Flying Bridge

• Carbon Fiber Hardtop

• Reverse Cycle A/C

• Washer/Dryer

• Dishwasher, Oven, Microwave

• Twin Side Board doors

• Cablemaster

• Generator (if not H-Drive)

The options above will amount to about an additional $400k.  Notice that we did not add the optional 1000-hp diesel engines.  We can think of far better ways to spend that $270k up-charge. For example, on a large fuel tank and doubling the battery storage capacity, which wouldn’t cost nearly so much.

Observations

First of all, the Greenline 58 Fly is a diesel-powered motoryacht that can stand solidly on its own two engines and does not have to have hybrid power to be an excellent choice as a motor yacht. When we compare her to other 58’ motor yachts, we find that she has some outstanding characteristics that have nothing to do with the hybrid option.

She is the beamiest boat — at 16’9” (5.12 m) — of 9 vessels we compared, and the second heaviest. She is nearly the only one that has three ensuite staterooms, and she is the only one with a hull and deck made 100% of vinylester resin. Vinylester resin is so expensive that virtually all boat builders only put it on the first or second coating under the gel coat.

The Greenline 58 Fly has the highest bow and the highest bulwarks forward of most boats in class. She’s the only one that offers a standard solar package.  Of the nine, she ranked #2 in fuel capacity, but with her optional 925-gallon (3500 L) tank, she ranks #1. She’s also the only one with an amidships multi-use compartment.

The Green of Greenline

Greenline is to be commended for pioneering the hybrid power concept.  By being well ahead of the rest of industry, this relatively new, boutique builder has learned a lot and is installing its sixth-generation of hybrid power. In the beginning, the hybrid power’s advantage was slow, short, quiet travel and supporting the concept of sustainability.

But now the Greenline 58 Fly offers somewhat more: If used in a regimen outlined in this report for long-range cruising, where the emphasis is on economy, enjoying the adventure, old-fashioned gunkhole cruising, and smelling the roses, she can travel over 1,600 miles and get something on the order of 2 nautical miles per gallon.  The 6,000-mile American Great Loop is a prime example of a cruise that should be taken slowly, for it’s not a race track. The same could be said of going down island or up to Alaska. Getting 2 nautical miles per gallon in a 58’ boat is as economical is cruising is likely to get any time soon.

Either way — hybrid or diesel-only — we think the Greenline 58 has a lot to offer.

Remember, life is better on a boat!

SEE OUR VR TOUR OF THE GREENLINE 58 FLY