The 'riv-olution' that made the 5000SY faster, lighter, quieter

by Mark Rothfield on 21 Jun 2011 In its former guise as the Riviera 4700, it had a top speed of 28 knots with 575hp Caterpillar C9 engines and shafts. Now renamed the 5000 and sporting Cummins QSC 600s driving Zeus pods, it achieves 33 knots.

Mid-range cruise figures are significantly better again, while fuel economy is enhanced by 12 per cent.

A few years ago the 4700 was deemed good enough to win the Australian Boat of the Year title and fortunately it was a relatively easy conversion candidate, for it had existing hull tunnels and sufficient cockpit floor height to fit the drives underneath.

Riv’s designers chose Zeus over Volvo IPS because the pods are a little more adaptable. There are other integrated attributes, like automatic trim, autopilot and a GPS-inspired 'Skyhook' system that holds the vessel’s position.

The 4700 was already 54 feet (16.7 metres) long once the platform and sprit were factored in, and actual hull length remains 50’9', so it really just brings parity between the dimensions and model designation.

Moving the motors aft demanded some juggling of fuel tanks and bulkheads to balance the weight distribution. In a bid to lighten the displacement, foam-cored timber veneer was used for drawers and cupboard carcasses, reducing weight without compromising the aesthetic appeal of the cherry, teak or beech facia.

The hull now rests appreciably higher in the water, and because the pods provide direct push the bow lifts a little higher. The ride is drier, especially at displacement speeds – the old 4700 tended to be nose heavy.

At the opposite end, the tender garage was a must-keep feature, and the designers managed to include room for a 3.1m Zodiac in between the Zeus legs. The lid opens electrically and the hydraulic boarding platform lowers about 450mm, so it’s a very easy launch and retrieval process.

There’s an appetite for life spent with a riesling, not a reel, in hand, so along with the option of a height-adjustable table that converts to a sunbed there’s now aft-facing seating and a table as well.

The icemaker has been shifted to starboard, and the galley sink and fridges are close enough to service the cockpit. Amtico flooring in the saloon can stand up to wet feet.

It’s the mid-cabin that has gained most from having pods. Where previously there were only double bunks, a lateral double berth now occupies the former machinery room. It also has a single berth.

The forward cabin’s island double berth runs more than two metres, so taller people can have a comfortable night’s sleep. It also has a spacious ensuite with separate shower stall.

To starboard is the third cabin housing bunk beds, although there’s the option of a foyer with leather lounge.

Now that there’s no engines underfoot the saloon is a noticeably quieter place. At slower speeds the engines emit a faint whir reminiscent of a passenger jet … manoeuvrability, meanwhile, is almost like that of a jetboat.

Compared to the conventional 4700 the performance almost defies imagination. There’s no planing transition, just smooth acceleration.

At full stick into a 1.5-metre sea the ride softness and noise suppression were apparent. To chew only 50 litres per side at 16 knots is pretty darn good, while to use 180 litres total at 28 knots is exceptional for a 50-footer.

The finish and fitout remain ever sophisticated.

For more information phone Riviera Marine in (07) 5502 Riviera Marine website