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Neptunus 650 Flybridge (2019-)

2 x 1,135-hp CAT C18 Acert

Brief Summary

The Neptunus 650 Fly is an ocean-going luxury cruiser. Semi-custom built to the owners’ specifications in St. Catharines Ontario, this 66’4” motor yacht blends performance, comfort, and strength with a high quality of fit and finish.

Key Features

  • Fly bridge wrap around seating with storage below
  • Fly bridge port side table with 4 stainless bar stools
  • Aft deck BBQ unit with cover
  • 4-burner ceramic stovetop, microwave, refrigerator drawers, and freezer/icemaker drawer
  • Dinette seats 6 people with large cherry wood table
  • Built in 14” LED flat screen TV with custom cabinetry
  • King size berth with memory foam mattress

Test Results

600 6.4 5.6 3.5 1.8 1.6 1810 1574.2 67
1000 11.3 9.8 14 0.8 0.7 799 694.8 73
1250 12.6 10.9 30 0.4 0.4 414 360.1 75
1500 15.8 13.7 46.5 0.3 0.3 336 292.5 77
1750 22.2 19.3 67 0.3 0.3 328 285.2 80
2000 27.7 24.1 95.5 0.3 0.3 287 249.7 82
2200 33 28.7 113 0.3 0.3 289 251 80
2250 34.6 30.1 118 0.3 0.3 290 252.4 81


Length Overall 66' 4''
20.22 m
Beam 16' 7''
5.05 m
Dry Weight 78,000 lbs.
35,380 kg
Tested Weight 83,505 lbs.
37,877 kg
Draft 4' 8''
1.42 m
Deadrise/Transom 19.5-deg.
Bridge Clearance 20' 7''
6.27 m (max)
Fuel Capacity 1,100 gal.
4,164 L
Water Capacity 300 gal.
1,136 L
Total Weight 83,505 lbs.
37,877 kg

Acceleration Times & Conditions

Time to Plane 6.9 sec.
0 to 30 8.2 sec. (0 to 20)
Props 31x40x5 Veem
Load 3 persons, 1/2 fuel, 1/4 water, 50 lbs. of gear
Climate 81 deg., 70 humid; wind: 10-15 mph; seas: 1

Engine Options

Tested Engine 2 x 1,135-hp CAT C18 Acert
Std. Power Not Available
Opt. Power Not Available

Captain's Report


Our test boat came with a single helm station up top and an optional ¾ flybridge enclosure, including real safety glass windshields with wipers.


The 650 Fly is designed to be owner-operated. It is comfortable for extended onboard cruising and stylish for entertaining while providing dependable offshore performance.

Major Features

  • Custom carbon-fiber hardtop keeps weight down
  • Walk-in engine room
  • Midship master suite
  • Yacht controller joystick and remote
  • Fore and aft thrusters
  • Fore and aft thrusters


The Neptunus 650 Fly layout chosen by our test boat owner was a three-stateroom configuration, master stateroom amidships, VIP stateroom forward, and a third suite off the passageway between the others. Each stateroom has its own ensuite.


The weight is kept under control with extensive use of carbon fiber for several of the components, such as the hardtop and swim platform.


For yachts in this price range, many builders keep the base price low but can overwhelm the buyer with options so extensive that the actual price may be multiples of the base price. The Neptunus 650 is just the opposite, with most items standard.



When it came time to fire up the mains, the procedure is pretty straightforward, with one standout. The Neptunus 650 Fly has a self-checking system at the helm.

The yacht self-checks… when systems are ready for getting underway these annunciator lights at the helm turn green. If any are red, then she’s not ready for engine start or getting underway.

We had a bit of a tight squeeze when departing our slip. The maneuverability of the 650 made it a non-event and highlights how anyone with a bit of experience can handle her without paying a captain for every trip. The combination of the straight shafts, huge props, and 15-hp bow and stern thrusters allowed us to ease her out and around with just a few gentle shots of the controls.


The bow rises up at speed underway and maintains this consistent attitude except when idling along.

Thrusters are Important. Even after leaving the marina, we had some tight maneuvering to do and it was completely without surprise or tense moments. Additionally, we had several holds for the many bridges we had to wait for. One got a good feel for the strength of the thrusters and how they’re able to not only hold off but push against a stiff crosswind. Again, no tense moments, and no thruster burn out. And we really worked them to make sure.


The 650 Fly was a dry ride, casting spray well wide.

The owner’s engine upgrade to twin 1136-hp CAT C18 Acert’s turning 31x40x5 Veem propellers through 1.97:1 reduction gears had plenty of power.


The weight and momentum of the 650 Fly easily shoulders aside a wake from another boat.

Once at our inlet, with open water ahead, it was time to push the C18’s and let her run. We discovered that she’s very responsive to the throttles, coming on plane in an average 6.9 seconds and getting to 20 MPH in 8.2 seconds.

WOT Speed

During our test, the 650 Fly reached a top speed of 30.1 knots in choppy conditions. We compared this to Neptunus’ factory test in calm conditions, they reported a top speed of 31.5 knots. So this just goes to show how sensitive even large yachts are to sea conditions.

Best Cruise. When we backed off to 2000 rpm and 24.1 knots, the 650 showed her best economy with a fuel burn of 95.5 GPH and a range of just under 250 NM, all while still holding back a 10-percent reserve of the boat’s 1100 gal (4163.8L) total fuel capacity.


At 88,255 lbs. (40,031.7 kg.) the 650 is a relatively heavy boat, but even when turning aggressively, there’s only a gentle 12-degree lean and nothing happens quickly, so everyone onboard will remain comfortable.


When hard turns are initiated, Neptunus 650 Fly drops her shoulder and we can see the spray coming off the bow. She’ll bleed off just a little speed but nothing of significance.


A 180-degree turn, with her electric steering, takes 35 seconds at 80-percent throttle.

Yachts in this class aren’t about hard turns, they’re about going straight and far and doing it in style, and it’s here that she again delivers. We had 1’ (.30m) rollers on our test that slowed us a little but did nothing to show how she handles rough conditions. Finding a stray wake showed her making a smooth penetration with no hull slap, with the bow throwing the water out wide.


We stopped to test the effectiveness of the SeaKeeper Gyro-stabilizer and found her holding fast with a 1-degree roll to either side. With it turned, off we showed 4’s and 5’s with the occasional 7-degree roll.

We brought the 650 back into the dock using the remote Yacht Controller, rather than the helm station. We were concerned about it losing connectivity or dying in the middle of a maneuver, but this never happened.


The yacht control pad activates the propulsion systems remotely, a remarkably convenient feature that allows the user to walk anywhere on the boat while still controlling movements.

One caveat though… always keep the bow of the controller aligned with the bow of the boat. If not, it’s easy to get disoriented and inputs will be opposite of what one wants. That said, we brought the 650 into the tight slip with absolute precision.



The hull is resin-infused glass with Kevlar reinforcements. As an example of the quality and attention to detail of the build, the wide-planked oak decking found in the salon sits on a 3” thick aluminum frame, topping another 3” (7.62cm) of soundproofing, and married to ¾” (1.91cm) plywood screwed and glued.

The Neptunus 650 Flybridge carries a CE rating of A-Ocean which covers largely self-sufficient boats designed for extended voyages through winds of more than Beaufort Force 8 (speeds over 40 knots), and significant wave heights above 13’ (3.96 m), but excluding abnormal conditions, such as hurricanes.


Neptunus builds the strength into the 650 Flybridge with Kevlar, the yellow skin seen here, added to both sides of the hull, all the way across from one side to the other. This is highly unusual and we’ve never seen this extensive use of it before. Kevlar is expensive but because it is so strong and does not stretch, it can eliminate the need for some glass in the laminate, which should make the hull lighter as a result.

All of the stringers for the engine mounts are made from Corecell A500 foam (which has a density that amounts to five lb. per cubic foot), and they are positioned with laser precision – literally. Neptunus uses Corecell A300 throughout the rest of the yacht. They’re all laid in, literally, with laser precision.


This Bosch laser level helps the layup team position the stringers within the hull precisely.


All of the structure is resin-infused which saves weight while adding strength. The combination of resin infusion and Kevlar should make the hull extra light and strong. It is also more puncture-resistant.

Boat Inspection

Aft Deck


The aft deck is under the protection of an extended overhead 6’10" (2.08m) off the deck, and supported by polished stainless-steel stanchions at the trailing edge.


The aft deck has split stairways to reach the large hydraulic swim platform, and boarding via the swim may be the chosen route. However, there is also a side boarding ladder, shown below, and splits in the guardrail amidship facilitate multiple options for a comfortable transfer aboard.


A removable stairway is fitted to the port side and an overhead grab rail is conveniently located.


The nearly 5’3” long carbon-fiber swim platform is rated for a 900-pound dinghy. The builder provides the cradle supports.


Aft deck seating consisted of a bench seat and a brightly finished mahogany table with flawless holly inlay work. Note the deck hatch in front of the table, which is a secondary access to the engine room.

With the outdoor grill on the aft deck and three folding deck chairs, a cookout for six people gathered around the table would seem natural. The sea of teak decking aft is a standard feature of the 650 Fly.


Capt. Steve is checking out the motorized shore cable switch hidden below this swing up cover. The hinged cover also hides the 14” mooring cleat with fairleads.


The Neptunus 650 Fly has a symmetrical layout with both side-decks being 17” (43.18 cm) wide and accessed from three steps.

A rail running the length of the house sides supplements the side rails that come up 28” (71.12 cm), exceeding safety standards. Side boarding is accommodated by a sliding section of rail amidships. Fully forward the rail height increases to 38” (96.52cm).



At the bow, sunpads measuring 6’8" (2.03m) wide by 7’1” (2.16m) fore and aft are mounted atop the trunk cabin and they easily convert to chaise lounge position with three different angles to choose from. Beverage holders are to the aft sides.

Ground Tackle


The windlass on the 650 is mounted on top of the deck. Rollers are integrated into 6” (15.24cm) toe rails for mooring lines, which means the lines need to be threaded through the captured rollers before bringing them to the cleats - keeping the tie-up in line with the chafing gear. A hatch just behind leads to the rode locker and a fresh water washdown.

The 200’ of chain rode leads over a polished anchor roller supporting a gleaming plow style anchor. For safety’s sake, a chain stopper takes the standing load off the windlass. To the sides are foot control switches, and further outboard are two 14” (35.56 cm) cleats.



The layout of the flybridge covers almost half the length of the 65-footer.


The flybridge is accessed from stairs to the starboard side of the aft deck. Storage is in the void area underneath the stairs and a stereo remote is just over the hatch. Note the LED courtesy lights at each of the teak tread steps.


On the 650, the bridge deck is large and eager for a party.

Flybridge Helm


The flybridge helm is the only one onboard. It’s trimmed in leatherette. The panel consists of 3- 16” (40.64cm) displays, with the CAT engine display centered over the wheel.

The compass is just below and in line with the steering wheel, which is mounted to a fixed base. We’d like to see a wheel with more rounded spokes that aren’t as hard on the fingers when spinning the wheel, but most of the piloting will be done by autopilot or the Yacht Controller.


On the upper left of the helm is the vessel line drawing with more annunciator indicators such as nav lights showing when active. A tri-data display alongside shows selectable information.

More of the leatherette material is on the lower dash, below which are the VHF, the Fusion stereo, the electrical switches and another set of annunciator lights for the vessel’s self-check system. To the right of the wheel are two round fuel gauges flanking more electrical switches.

A great feature - bilge pump counters, resettable to zero, that track the amount of water pumped. Above is the yacht controller joystick, the bow and stern thruster controllers, trim tabs, and the SeaKeeper gyro control screen.


On the side are the CAT engine throttle controls, the second VHF, the Simrad autopilot, and the grid controller for the forward screens.


The helm seats include flip armrests and bolsters. Leatherette upholstery is diamond stitched. Below the wheel is an angled footrest, and the teak decking seen throughout the flybridge continues here.


The zippered flybridge enclosure is mainly isinglass. However, two panels are fixed tempered safety glass and include wipers.

This is an important detail as wipers don’t work on isinglass and looking through it in the rain is problematic. This single detail makes the fly-only bridge work. The isinglass panels on the centerline can open to allow air to flow through.


The flybridge is fully enclosed and climate controlled. It features several distinct social zones, including lounging space and a dining area. The table is on a 10” (25.40cm) elevated platform. It includes four stools in fixed positions and air-conditioning vents outboard and below.


Opposite the dining table and behind the helm seats is a quartz bar top with storage below, flanked by a sink and icemaker.


A serving area with a fridge and storage below flanks the beautifully finished pedestal-table surrounded by J-shaped seating with plush padding and leatherette upholstery.

To the port side of the helm is a lounger with a back that adjusts into multiple positions, both forward, and aft facing.

Overhead, a custom made carbon fiber hardtop adds protection from the sun. The top is supported by heavy-duty stanchions and includes lighting, speakers, and opening hatches.


The salon of the 650 Fly is a comfortable seating area for six adults. Its’ open atmosphere comes from the high 6’8" (2.03m) ceiling upholstered in Ultraleather and surrounding windows trimmed in high-gloss cherry. Solid wood flooring is standard.


The salon looking forward to the raised galley. Note the wood trim panels on both sides of the overhead, these cover the A/C vents.


Entrance to the salon is through elegant curved glass sliders that are rarely seen. They provide an opening of 41” x 70” (104.14 cm x 177.80cm).


The salon represents a welcoming social zone with opposing seating consisting of a leather upholstered C-shaped sofa to starboard, wrapping around a solid cherry wood table.


The salon sofa has storage and courtesy lighting under the seats, and is secured to the deck. The oak decking runs from bulkhead to bulkhead, not up to the furniture.


Opposite the sofa are two chairs and an end table with the 49” (124.46cm) TV mounted just ahead.


The galley of the Neptunus 650 Fly follows an American-style kitchen with full-sized appliances and a center island.


Neptunus includes every appliance found in upscale homes. The center island houses the dishwasher.


An attractive stemware case is just to port. There’s plenty of open counterspace beneath, with opening side windows to the outboard side. Below is storage that includes a wine chiller and a trash compactor.

Jenn-Air refrigerator and freezer drawers are just forward of the full-size oven, with a four-burner induction cooktop just above. A convection microwave is in the overhead cabinetry. More opening windows are provided to this side. The stainless sink is corner mounted.


Ahead is a dinette with an upholstered wraparound settee surrounding a quartz table. Expansive windows provide outstanding views and natural light.


The dinette, which seats six people, is on a raised platform.

Lower Decks


The lower accommodation deck is accessed from curved stairs to the port of the dinette. The house electrical panel is located in the stairwell.


The woodwork is indicative of the quality fit and finish seen throughout the 650. The master is located down a few steps from the upper stairwell.


In the hallway at the bottom of the stairs, Capt. Steve inspects the laundry closet containing a stacked washer and dryer. Behind him is a linen closet.

Master Stateroom


This full-beam stateroom features a center-mounted king 79” x 67” (200.66 cm x 170.18 cm) berth, a comfortable 27” (68.58 cm) off the deck.

The decorative element found in the salon is repeated in the master suite above the nightstands to both sides of the bed. Light from the large hull-side windows with integrated opening portlights plays on the matching grain cherry chests of drawers to port and starboard.

Accent lighting under the drawer sets falls on the wall to wall floor covering.


All staterooms include full-length cedar-lined hanging lockers. The finish is a high gloss book matched cherry with leather trim.


The master stateroom overhead measures 6’5” (1.96 m). The optional SeaKeeper stabilizer is underneath the bed.



The master head includes a walk-in shower with a solid glass door, a bench seat, and an opening portlight.

VIP Stateroom


In typical fashion of a bow stateroom, there is an island berth 66” x 58” (167.64 cm x 147.32cm) accessible from both sides.

The same headboard treatments from the master are repeated here. Storage is over the portlights, under the berth, and in the full-length hanging lockers.

On the aft bulkhead, there’s a 24" (61 cm) TV and just below is a convenient shelf where there would otherwise be wasted space. Headroom here is 6’9” (2.06 m) which leaves 3’7” (1.09 m) above the berth.

VIP Head

Just to port of the entry is the door to the ensuite head.


The VIP bath has a sink recessed into the quartz counter, an opening port light, and a walk-in shower with glass door and teak decking.

Third Stateroom


Back out into the passageway is the third stateroom. The aftmost door is the entrance to the cabin and the door to the left is a second entrance to the head, so it can be used as a day head without need to go through the cabin.


The third stateroom features a double berth with opening portlights. Storage is above, below, and in a cedar hanging locker. On the inboard bulkhead, there’s a 24" (61cm) TV with a bookrack just alongside.

Crew Accommodations


This large stern hatch leads to the optional crews’ quarters with a pass-through to the engine room. The engine room has another access hatch on the aft deck so that day checks can be made without disturbing the crew.


Crew and engine room access is via a transom door ahead of the hydraulic platform which might be a tad wet if underway.


Inside there is a shower behind a curtain to starboard, and a sink and toilet. A berth is just opposite.


The crews’ quarters also include the main electrical panel with battery switches to the side. At the head of the berth are vents blowing volumes of air into the compartment and a 32” (81.28 cm) TV. The engine room is just ahead.

Engine Room


There’s 5’9” (1.75m) headroom between the deck and the overhead which contains 3” (7.62cm) of soundproofing material. There are also fully encased 24v emergency lights to supplement the 110v fluorescent lights.


There’s enough room to walk between the twin CAT C32 engines. Notice all service checkpoints are inboard for better access. The sea strainers and six through-hulls are in line right between the engines, and fitted with easy to reach shutoffs.

Everything is well-labeled, all hoses are double-clamped, and all components are electrically bonded. There are six bilge pumps onboard with two in this compartment.


The 1000-gallon fuel tank is the forward bulkhead. The blue electronic fuel shutoff valves across the top close automatically in case of fire. Dual Racor filters for each engine means filters can be changed while underway. The sight tubes in between allow for checking the fuel status at a glance, no sending units necessary, but the boat has them. An oil changing system is just below the Racors.

On the port engine room bulkhead, starting aft is the control for the seven-ton chilled water Dometic air conditioning system. If amperage from shore power is insufficient, one can change the capacity of the chiller, dropping from seven tons to four to accommodate going from 24,000 to 12,000 BTUs.


The blue boxes are battery charging systems, 100-amp for the house batteries, 30-amp for the engine start, bow and stern thruster batteries. The isolator system is just ahead. Note the silver opening for fresh air intake just above the battery chargers.


Looking over the top of the starboard engine, we see the hot water heater on the left and a T-5 blower. Just abaft over the black hose is a water/gas separator for the generator exhaust. It directs the cooling water below the waterline and the exhaust gas above. The water discharge for the air conditioning is also below the waterline.


Looking aft from between the engines, on the left is the 21kw CAT generator. Under the stairs is the A/C unit. The ladder gives access to the engine room when it is too rough to come in through the transom.

Safety is well thought out. In the event of a fire, the air dampers to the Delta T air filtration system to close off the air supply, the fire suppression system discharges, and the electronic fuel valves close off. The well-laid-out engine room demonstrates that ease of use was a priority for Neptunus.

Optional Equipment to Consider

  • Upgrade to Cat C18s 1136 HP – $50,000
  • Custom flybridge hardtop – $46,700
  • ¾ flybridge enclosure – $24,500
  • Dual 16,000 BTU AC on fly – $31,000
  • SeaKeeper 9 – $95,000


The Neptunus 650 Fly is every bit the cruising yacht she was intended to be. She’s got a comfort level and the performance that match her style.

We like having a single helm on the flying bridge as it frees up room on the main deck. However, making the canvas and isinglass tight is important, as are the tempered glass windshields. With climate control on the flying bridge, there is no reason why this yacht can’t be used in most seasons. Eliminating a heavy hardtop or fiberglass enclosure keeps the CG lower. In addition to her CE Category A Ocean certification, this boat is also ABYC certified.