Shell Riviera Racing Tencara

Charging down the course, the engines of this high-tech racer are reaching their unique crescendo.

The track's rougher than I remember it, in fact I'm thankful now for the six-point harness that was such a pain back in the pits. Without it, I'd be channelling way too much input into the thick-rimmed wheel - not a good thing when the power-assisted steering is around one and a half turns lock to lock.

Thump! I feel the bump through the Corbeau race seat's thin base padding and we pitch just a touch sideways. I catch it but in the gusty conditions overcorrect just a touch. Concentrate - at over 140kt almost 7000kg is balancing on a knife-edge... Well, two knife-edges to be exact.

Then it happens... Right on the fast line appears a local, doing his best Rex Hunt impersonation - a fishing rod in one hand and the controls of 12 feet of classic Quintrex tinnie in the other!

Not the sort of hazard you expect to encounter on a normal racetrack. But then this is no normal racetrack, and strapped onto my butt is no ordinary racer.

Rex's blood brother has newly found boat handling skills and executes a U-turn in the dinghy's own length by the time we're back through the 100kt mark. It's not even close but my co-driver takes the hint and pulls back the twin throttle levers. My ride's just about over and Shell Riviera 204 settles back to a slow plane at about 60kt - faster than even the best production skiboats can manage WFO. It feels like I could get out and row faster!

WHAT THE F$$$
Welcome to the world of offshore powerboat racing. In particular welcome to Class One UIM, the playground of the rich and famous, and one of the chosen R&D arenas of Australia's biggest boatbuilder, The Riviera Group.

With fewer than 30 of these boats racing around the world, Class One is the waterborne equivalent of Formula One. It's fast, hideously expensive and electrifyingly addictive - especially from behind the controls.

Any resemblance between Riviera 204 and the average pleasureboat are purely coincidental. Sure, they both float, but the similarities end there.

Built in Marghera, Italy by bespoke raceboat builder Tencara, the barebones composite hull and tub that is the basis for Riviera 204 costs upwards of a cool $500,000... US dollars.

Just over 12m in length with a beam of 3.6m, the Tencara is an asymmetric planing catamaran. Asymmetric relates to the cross-section of the sponsons (the bits in the water... Just!). The inside edge is close to straight up and down for bite on the turns - and oh how it bites - while the outside is shaped like half of a very deep, very fast canoe.

One of the key benefits of this style of hull is low drag - important in any form of racing. There's also very little resistance to wave action, and a nice big tunnel between the hulls that captures air and cushions the ride. Unfortunately this tunnel also creates more than a little lift. Ever seen those pictures of raceboats flipping? Hold that thought.

Tencara is to Class One, what Reynard is to Indycars. If you're not running one, you're not winning. The choice of the frontrunners in world-level racing, they are keenly sought.

DIESEL BUT NO DUST
The normal powerplants mated to the Tencara hull are marinised 12-cylinder Lamborghini petrol engines. Given Riviera's flybridge cruiser background it's probably no surprise that Team Riviera's chosen powerplants have humbler roots.

Diesel. That's what powers this beauty - though they are hardly your average trawler motor. For a start they're supercharged, as well as turbocharged, and intercooled and mechanically-injected. Oh, and by the way, they're also two-stroke.

The basic architecture is one of the most popular and proven powerplants in the diesel world. Originally designed for military use (WWII) with a hitherto unassailable power-to-weight ratio, Detroit's venerable 8V92 is a 90° V-eight, which in standard form displaces 92ci (about 1.5lt) per pot.

In this incarnation, the engine's standard piston port induction, transfer porting and pushrod-actuated poppet valve exhaust configuration is retained but just about every component is specially sourced - though not necessarily race-derived. The block for instance is a military-spec unit from the USA (built like, or was that for, a tank!). Those exhaust valves and springs mentioned above are from (wait for it) a Suzuki Vitara compact 4WD.

The Class One rules allow petrol engines to displace 8.0lt, with naturally aspirated diesels allowed 16.0lt. Forced induction attracts a penalty ratio of 1.4, thus the 8V92s in Riviera 204 can displace over 11.0lt. In fact, Riv 204's powerplants are around 9.8lt thanks to a de-stroked crank from a classified source based in France.

Taking a trick out of the V8Supercar and Superbike tuners' books, longer conrods are fitted (supplied by V8Supercar stalwart, Harrop Engineering) and Riviera Racing has developed its own slipper-style high-performance pistons.

The Roots-style blower is also RR's own work and closely guarded, the turbos are big hand-built bespoke units from Garrett in the USA.

The intercoolers are sourced from the Detroit parts bin - they are more commonly found on the version of this powerplant that pushes locos across the Rocky Mountains. I guess this is the right place to say that this thing pulls like a train!

Like any race engines, 004's mills are much more than the sum total of all their parts. There are countless hours and plenty of soot on the equipe's Gold Coast engine dyno and a whole learning curve behind the 1350hp-plus/3000ft-lb mills.

As well as ensuring boost levels are below the championship mandated maximum (about 3bar) at all times, there's a unique combination of performance required from these powerplants. Enough torque to get 7000kg of machine out of the hole, no visible emissions, and the ability to stay together when the inevitable big free rev happens when boat and props leave the aqua azul and become airborne.

Riviera Racing's engineering team headed by engine builder Mick Glanister can be justifiably proud of the powerplants they have created. A well-informed little bird revealed that these powerplants at idle each produce more than a V8Supercar's max-power and max-torque!

They'll also rev well past the 4000rpm mark - big revs for a near-10lt engine.

At the business end of all this power are custom-made, surface-piercing, five-bladed Rola propellers. Not exactly your run of the mill prop, they cost in the region of $6000 each (two required) and are designed to run with just the tips of the blades in the water.

Like a racecar changes gearing for different tracks and conditions, so RR changes props for different sea conditions and courses. Onboard Team Riviera's transporter (worth a story in itself) there are a minimum of four matched sets of props. Do the maths.

THE USUAL SUSPECTS
Wearing Shell and Riviera livery, 204 is one of just two Class One boats currently competing in Australian Offshore Powerboat Championships. The other is the Jager Racing boat of colourful Gold Coast hairdressing identity, bon vivant and multi-time Australian champ, Stefan.

For 2002 it's hoped as many as five of these craft will run in a full championship with rounds at venues right around Australia and, possibly, Auckland.

The regular driver of Riv's racer is Paul Lidgard - another multi-time Aussie champ. Riviera founder and owner, multimillionaire and general all-round petrolhead, Bill Barry-Cotter, is the man beside Lidgard on the throttles.

Like rally driving, punting a Class One is very much a team effort. There's more to throttling these racing machines than a strong right arm, and even after my short drive I can also vouch for the the fact that there's way more to driving them than just keeping the sharp end pointed towards the turning mark.

Throttling is an art all in itself. As the boats do not have gearboxes and the props are designed to spin hard at very high speed, getting off the line is a real skill.

Too much, too soon and you can literally drown the engine causing potentially catastrophic damage. Too little and you don't go anywhere.

Indeed, there's a real art to juggling the throttles as the boost builds, first via the supercharger and then from around the 1300rpm mark via the big Garrett turbos.

While this part of the operation depends largely on sound and feel, there's a bank of Motec electronic and allied analog gauges by which Bill judges the health or otherwise of the mills throughout the race. There's also plenty of data download capability.

What would normally be shift lights in an automotive environment still monitor engine revs, but tell a different story. They make sure Bill's on the ball and is throttling back to reduce free revving when the whole plot's airborne between waves. Of course, he's also got to be ready to goose the throttle levers to retain that critical boost and momentum when the props bite again.

Unlike a racecar, there's a whole swag of navigation instruments as well. Practice usually involves recording headings from turning mark to turning mark. In the race these numbers are all-important as the driver's view from the jet-fighter style cockpit is somewhat limited, even without the spray and roostertails associated with traffic.

Retaining corner speed and therefore boost are the essence of good driving in this style of racing. The nature of the beasts' powerplants preclude the ability to charge into a mark, stop, turn and blast out.

Sweeping arcs, with plenty of throttle and the driver delicately balancing the whole plot makes for a good laptime. In fact, anybody who has driven an older 911 fast will recognise the feeling the Tencara hull channels through to the wheelman. Again in car terms, at racing speeds extreme oversteer is only a knife-edge away. Try and tighten that turn one more degree and you could end up exiting the course backwards... At best.

If the unthinkable happens and the whole thing turns really pear-shaped, there's a SCUBA rig adjacent to each seat with donkey bottles that give about 15 minutes of air. By my reckoning, 15 minutes upside down underwater would be a rather peaceful hiatus in comparison to the debrief and damage estimates a high-speed loop would generate from Barry-Cotter and the rest of the Shell Riviera Racing crew.

THE BULL$$$$ STOPS
My drive comes during practice for a round of the championship on Geelong's Corio Bay. A gentle breeze of around 25kt has chimed in from the north and is making conditions generally unpleasant. Add to that your normal complement of pleasureboats, the relatively confined environs of the bay and the odd anchored bulk carrier and there is potential for calamity.

Once into the cosy cockpit and strapped in, the view is dominated by the vast foredeck and, w-a-y out there, the picklefork points of the hulls.

A conventional rally-style intercom connects throttleman and driver and once the nose is pointed in the right direction (it's not the sort of craft that's easy to handle in the confines of a marina!), a push of a button has each mill up and running. The noise is part top-fuel hemi and part Hume Highway semi with more than a dash of mechanical blower drive filtering through your helmet.

As the craft climbs onto the plane there are five seconds or so of blindness as that big foredeck blocks out the view. All the time the engines have your attention... Winding up, starting to generate an off-beat cadence that's hard to get out of the system still.

Then free of the binds of its own wake, the turbos playing their shrill song, the big Riv settles onto a flat plane and you're away. How fast do you want to go?... Just dial it in.

At 1500rpm the props are barely biting and we're in settle-in mode at over 80kt. Another centimetre or so in the throttle quadrant and there's 2000rpm on the tachos and we're tracking upwind with 105kt registering on the GPS.

The coast (and bay) is clear and Bill takes it to race pace. The engine note deepens, the turbos go up an octave and in a blink of the eye we've added 30kt and 500rpm. Into an extra 20 or so knots of wind there's around 150kt over the front deck and things are getting a little frisky.

Course corrections at this speed require the most delicate of inputs, a point Bill reminds me over the cans. Channel markers and anchored boats go past like white posts on the highway. A large gull is slow taking off and threatens to do a grasshopper impersonation on the armoured plexiglass screen.

There's constant talk between Bill and yours truly. I try a tight turn to port and then to starboard, making sure to make him aware that I've picked out boats and other obstacles and which side of the mark I'm turning. That way I figure he's gaining some confidence in me and keeps the neddies fed in.

In what seems like just a moment, it's time to head back to home base, a downwind run of several miles. Again the engines wind up out of the turn and this time there's no holding back. Running with the wind the boat feels planted and the 2700rpm flashes past on the Motecs...

Over the intercom comes a steady but clearly animated voice. "That's 145kt. Over 160mph..."

We hold it there for what seems like just a few seconds but is probably a couple of minutes. The intercom is quiet and the engines are singing as we both savour the ride. And then all too soon, thanks to Rex it's over...

What a boat! What a buzz!