GREENLINE’S HYBRID CHOPS
A closer look at the new Greenline 36 Hybrid
from Slovenia has made a specialty of offering hybrid yachts under the Greenline banner and they have been pioneers in the development of both electric and hybrid versions of their advanced designs. With experience taken from hundreds of hybrid motor cruisers, this new 36 is the latest manifestation of the Greenline electric power philosophy, and it offers some very interesting cruising solutions.
The 36 is available in several variations. You can have it as a fairly conventional diesel-powered motor cruiser equipped with a Volvo Penta or Yanmar engine. The choice of Volvo power gives you the option of a hybrid version, which allows running under either diesel or electric power but not both at the same time as happens with some hybrid concepts. The 370-horsepower Yanmar diesel does not have the hybrid option but you do get higher performance with speeds up to 25 knots. The Volvo Penta 220-horsepower diesel provides a top speed of 18 knots, but switching to the electric power drops the top speed to 6.5 knots.
All these powering options forced Greenline to find a hull design that would operate effectively at both low displacement speeds and higher planing speeds. Greenline says this is the fifth-generation hull and is the result of extensive tank testing. Out on the water where it counts, the hull seems to live up to the claims, although it is quite sensitive to trim. On the sea trial, the trim tabs were not working, so experimenting with trim variations was a bit limited.
Starting at the bow, there is the now fashionable vertical stem matched to a low, double chine line. Below the waterline, the hull is quite flat with just a shallow vee to cushion the ride. A wedge built into the transom helps with the trim, and a shallow tunnel accommodates the propeller and reduces the shaft angle. This is a single-engine cruiser, so the propeller and its tunnel are on the centerline of this semi-displacement hull.
Such a shallow hull would not have much bite on the water, which could make for poor directional stability. To compensate for this, the designers have added a fin about a third of the way forward from the transom. At low speeds this certainly gives the 36 good directional stability, but at full speed, the steering becomes a bit twitchy as it tries to pivot around this fin. Lowering the tabs would probably have sorted this, but as mentioned they were not operational during our trial. Greenline does not provide the fin on the higher-powered Yanmar diesel models, which underlines its effect on steering at higher speeds.
The relatively flat shape of the hull makes the 36 efficient, and the performance is good for the modest power available. Under diesel power, she was responsive to the throttle and turned sharply and precisely, as you might expect with that fin providing a pivot point. There was a fresh breeze blowing on the sea trial and at speed the hull generated a lot of spray, which is likely to be worse if the bow is trimmed down at speed. Ease back on the throttles to a 15-knot cruising speed, and everything was much more comfortable.
Under electric power only, the ride is smooth and there is virtually no wash, which makes it ideal for river and lake cruising, or a perfect Loop boat. The sound levels are not as low as I would have expected, with a low rumble from the engine compartment, but the balance is made up from wind and hull noise which of
course are common to all boats. I measured 57 dB(A) under electric power compared with 71 dB(A) at cruising speed with the diesel running, both of which are relatively low figures and make conversation comfortable at the helm.
Forget about the propulsion and the hull design for a moment, and the 36 presents a very comfortable cruising boat. It is certainly good-looking from the outside, with low, sleek lines, an asymmetric superstructure offset to the port side, and sloping supports give the boat a dynamic look. Offsetting the superstructure allows a wide, safe passage to the foredeck on the starboard side and easy access from the sliding door alongside the helm. Large solar panels on the top of the superstructure can pump out in excess of 1kW of electric power in bright sunlight, which helps to keep the batteries charged. A short mast keeps the bridge height low but provides a mounting point for the antenna. A narrow side deck on the portside is wide enough to set fenders and mooring lines when coming alongside. One small point with the fairleads though: forward and after fairleads have sharp edges that could chafe the mooring line.
A great feature of the cockpit is the electric transom door, which folds down to provide easy deck-level access to the cockpit from a standard-height marina pontoon. You simply step onboard without any of the acrobatics often associated with boarding. This easy access could probably work for a wheelchair, because it is level with the afterdeck. When you leave the boat, simply press the button on the remote control and the door closes, although one snag with this door is that its top is too low for safety when it is closed at sea.
The cockpit has been kept simple with seating only down each side. Portable tables could be used to supplement this seating and there is sun protection from the superstructure extension above. One option would be to have enclosing screens fitted around the cockpit so it could still be used in poor weather. A single sliding door gives access to the saloon and the after window on the port side can be hinged up to help link the galley directly to the cockpit area.
The galley occupies most of the after area of the saloon. It has a two-ring induction cooktop, let into the countertop, and a tiny sink, which is barely big enough to fit a dinner plate. Greenline plans to increase the sink’s size on production models. On the starboard side, there is a huge domestic upright fridge and freezer, holding enough for a long cruise. The microwave oven is on this side as well. As it stands, the galley is pretty basic and in my opinion, upgrading is called for.
Farther forward on the portside lies a large, U-shape settee that surrounds a table, and this is the main relaxing area when the cockpit is out of use. It looks comfortable enough and it sort of faces the optional rising TV let into the lockers on the starboard side. This television takes away a lot of stowage space when lowered. Large windows offer a great view of the outside world, which is also a benefit for the person at the helm, although the high galley lockers and the fridge aft can make it hard to spot anything coming up astern.
The double cabin in the bow has two single berths that you can push together to form a double or keep them split as V-berths. On the portside there is another double, but this one has minimal headroom over much of the berths, and there is standing headroom only in the entrance area. This could be a cabin for a couple, and the general arrangement plan shows the least amount of headroom at the after end. Claustrophobic guests may want to sleep with their heads toward the bow.
These two cabins share a single head, with an entrance to the forward cabin and access from the short passageway that serves the two cabins. For a 36-footer, the shower is surprisingly large and an electric toilet is one of the options. This accommodation is perhaps a bit more basic than one you might find on competing cruisers of this size, but the shallow depth of the hull limits the space.
AT THE HELM
Greenline has given good priority to the helm station and in general it works. The helm seat offers both standing and sitting options and there is a complex footrest that can convert to a platform for those who prefer to stand. The throttle/gear lever is a standard Volvo Penta unit and works for both diesel and electric propulsion, with a selector switch allowing you to convert from one to the other so the power changeover is very simple.
I didn’t love the shiny black finish to the dash panels, which could cause nasty reflections when the sun shines
through the two glass hatches overhead. There is space for a large combined chart plotter and radar display and other equipment here with the lower panel given over mainly to the controls. There is a display that shows both the battery status and how much charge is left, as well as the time before the battery expires. All that to give peace of mind to the captain when running on electric power. The knobs on the VHF radio installed at steering-wheel level can catch your fingers and more thought needs to be given to the whole helm layout, although the sightlines are excellent, except for that partially blocked view astern.
In standard form, the 36 comes well-equipped and even air conditioning forms part of the standard spec. The bow thruster is also standard and improves handling in marinas, but a stern thruster is an option—I would call it a necessity—with the single engine installation if you want easy berthing. Even in the fresh wind of the sea trial, docking was controlled and accurate with the dual thrusters.
Now for the fascinating part of the Greenline 36: machinery installation. Developed by Volvo Penta along with electric specialist Siemens, the diesel sits under the saloon sole, and a generous access hatch allows you to easily reach all of the maintenance bits, most without even going down into the compartment. The electric motor for propulsion sits in line with the diesel crankshaft and is separated by a clutch so that the diesel can be isolated when the electric motor is powering the boat. With this arrangement, both the diesel engine and the electric motor operate the propeller shaft via the conventional gearbox, but they do so individually.
When the diesel is operating, the electric motor is turning and becomes a generator that produces 7kW that is applied toward charging the boat’s 48-volt lithium-polymer battery bank. This can also be charged from the solar panels, and, of course, by shore power. There are separate conventional battery banks for the engine start, the bow and stern thrusters, and for domestic supply. An inverter converts the 48 volts of lithium batteries up to 110 of 220 volts AC for powering the domestic equipment and the air conditioning. Greenline reckons that the batteries have enough power to remove the need for a generator.
Hatches in the afterdeck open onto a generous storage area, which is suitable for bikes, fenders, and a deflated tender. However, the steering gear and the gearbox/propeller shaft are not protected so anything stowed here needs securing to prevent it from interfering with these important parts of the boat. A storage box might make good sense in this compartment.
The Greenline 36 makes an interesting and different motorcruiser concept. For those who want a quieter and supposedly greener approach to boating, it offers viable options while not compromising the capability of going faster or extending the range in open-sea cruising. It is a great-looking cruiser and has many innovative features, and while there were some faults with
this prototype, it is likely that these will be ironed out of the production versions. There is a long list of optional equipment that can be added, many of which most owners are likely to consider essential.
There are several types of hybrid power designs for boats and Greenline has come up with an interesting solution that can meet many of the requirements of the cruising sailor. However, don’t be misled into thinking that you are saving the planet with this type of hybrid. It’s not like an automobile where you can recover energy when braking or going downhill. Boats don’t brake and only go downhill when sinking.
Apart from the solar panel, you don’t get any electric power for nothing. Indeed when the motor becomes a generator you are losing about 10% of the power every time it goes into the battery and a further 10% when it comes out again—and this is power being generated by the diesel engine. You can recharge the batteries from shore power in harbor, which can be a cheap option, but that shore power still has to be generated somewhere, so it is not entirely green.
Then you have a limited amount of power in the batteries and you have to make choices. You have about 20 miles of running from a fully charged battery which could be enough for a short day cruise before you need to switch on the diesel. You could run the air conditioning for six hours before the batteries run out, so overnight you might find you have to start the diesel to get enough battery power to boil the kettle for breakfast. You have to think about how and when you are going to use the power that is available in the battery bank. A hybrid system gives you options and it is up to you to choose which options to use, which certainly adds a new dimension to cruising.
The newest iteration of the Greenline 36 Hybrid strikes a modern pose, inside and out. 42 passagemaker.com May/June 2017
May/June 2017 passagemaker.com 43
Large light ingress is enhanced by a seamless forward windshield, and skylights and light veneers help add to the feeling of refinement.
Left: Access to the Volvo-Penta diesel- electric propulsion is under the saloon cabin sole.
LOA: 39’ 3” Beam: 12’ 3’ Draft: 2’ 9” Disp: 15,432 lb. Fuel: 153 gal. Water: 88 gal. Engine: 220-hp Volvo Penta D3; Optional engine, single 370-hp Yanmar 8LV Electric Motor: 10 hp Design: J & J Design Builder: SVP Yachts www.greenlinehybrid.si
Above: The transom completely opens up—handy for boarding or taking a running leap into the water. The flush deck through to the pilothouse is a nice touch, particularly with the galley aft.
Contemporary appointments abound, like this split- convertible forward berth that also echoes the main deck, with loads of natural light.
The Greenline 36’s bench seat helm allows easy access to the side decks for fenders and lines, as well as the safety of high bulwarks.