Fleming nose way to cut fuel

Fleming Yachts' new flagship, the Fleming 78, appears at first glance not to be much different from its previous standard-bearer, the Fleming 75, launched in 2000.

But designer Tony Fleming did want to improve the shape of things below the waterline.

That may surprise those who know his work, mainly because Fleming's designs have always enjoyed a better-than-good reputation for seakeeping and efficiency. They tend to be semi-displacement with moderate deadrise, a fine entry forward and a hard-chined, modified vee aft.

They have, in the past, been specifically designed to be able to cruise at up to 20 knots but be at their most efficient at 9 or 10 knots.

However, before starting to draw this new 78, Fleming believed he could do even better in the area that now matters most to the majority of his clients - improving fuel efficiency at speeds below 10 knots.

His main weapon in this quest has been the addition of a bulbous bow.

This extends nearly 1m forward of the original stem and is also made as a separate attachment that can be retrofitted to the Fleming 75.

The other major below-the-chines change was a 1m extension to the aft hull under the swim step.

As well as creating more waterline length, this extension adds more buoyancy aft and greatly increases storage space in the lazarette - never a bad thing, especially on a passagemaker.

Fleming has retained the full-length keel which extends below the rudders and propellers and provides excellent protection in the event of a grounding.

Although any improvements above 10 knots are negligible, at the slower speeds on which he was concentrating, the benefits are substantial.

For example, at 8 knots there has been a 13 per cent saving in fuel.

This has also resulted in a greater range for the F78. With the same fuel capacity as the F75, the F78, at 8 knots, can travel an incredible 500 nautical miles further than its smaller sibling.

Even at slightly higher speeds, the savings are impressive: 10 per cent at 9 knots and 7 per cent at 10 knots.

The F78 is certainly no slug. Thanks to a pair of 1000hp MAN V8 diesel engines, running 38.5" x 34" four-blade propellers, it can hit 19 knots.

But to move this 74.9-tonne boat at that speed will reduce the fuel in the tanks by a hefty 405 litres an hour.

At 2000rpm, the F78 will make 15 knots, but the fuel consumption drops to 244 litres an hour.

At 1500rpm, the 12 knots achieved will cost less than half again - just 112 litres an hour.

Unless you are trying to outrun the weather, speed is rarely a priority for ocean-going passagemakers.

The comfort of those on board, looking after "the gear" and preserving fuel are generally far more important than arriving a little sooner.

For those who own and use such boats, the ability to go another 500 nautical miles before refuelling will be a real bonus.

Fleming has also concentrated on trying to make life on board as comfortable as possible. For example, as on the F75, he has incorporated an Aquadrive anti-vibration system in the driveline. This acts as a thrust bearing, transferring the thrust from the propeller directly to the hull, not the engine. The connection to the gearbox is also through a constant velocity joint, minimising alignment issues and letting the engine float on soft engine mounts, and the gensets are on anti-vibration double mounts.

Lead-lined sound insulation around machinery makes the F78 as quiet as possible while under way.

Construction is also of a style appropriate to the type of seriously challenging sea conditions likely to be encountered. Solid, hand-laid fibreglass hulls are reinforced by an interlocking matrix of frames and full-length box-section stringers.

GRP fuel tanks are glassed into the vessel's structure on all sides, making them an integral part of the yacht and adding to overall hull rigidity.

Given that these types of boats are very individual - as you would expect with a price-tag of about $6 million - much of the interior is built on a one-off basis to client requirements.

However, the dinette area does come in a standard form, with a curved banquette, oval dining table and storage cabinets with sculptured glass doors. Designer lighting is also installed over the table with a dual-circuit dimmer control. The saloon, galley and dinette spaces boast a combined area of 32.5sq m.

They flow together to form a luxurious area made even larger by the extension, through the aft doors, of the saloon on to the California deck - an enclosed, raised section of the cockpit protected by the overhang of the top deck.

Accommodation centres on the owner's stateroom.

This is a full-beam affair, featuring a king-size bed able to lift hydraulically to provide access to the large storage area beneath, a walk-in closet and an en suite with either a shower stall or a whirlpool tub - complete with a thermostatically controlled mixer valve and a fibreglass-lined enclosure.

Overall, the interior design is of superyacht standard, with a stunning main helm station reminiscent of a far larger boat, curved timber-lined staircases and a huge split-level flybridge.

The flybridge includes a small but practical second helm, complete with an electronics console that retracts out of the way when not in use, a large entertainment area which can seat a dozen, double barbecues, fridge and icemaker, and a large boat deck equipped with a 4.2m, 700kg capacity stainless-steel davit and able to accommodate a 5.2m tender.

For those Kiwis interested in such ocean-going vessels - and there are a surprising number of them these days - there is a wide choice.

Many, including the F78, are built in Taiwan or China, but that is no longer the issue it once was.

All are built to very high standards - in this case, European CE certification for ocean class.

However, Fleming, unlike many competitors, has an agent here, Orakei Yacht Sales, so those seriously interested do not have to travel far to get the information they need.

Fleming 78

LOA: 24.84m

LOH: 23.66m

LWL: 20.05m

Beam: 6.52m

Draft: 1.52m

Displacement: 74.9 tonnes

Construction: GRP

Engines: Twin 1000hp MAN V8 diesels

Maximum speed: 19 knots

Cruising speed: 10 knots

Fuel capacity: 11,356 litres

Water capacity: 1892 litres

Want to know more?
Check out Barry Thompson's boat review on the Fleming 78 in the September/October issue of Pacific Powerboat magazine.