America's Definitive Marine Engine Magazine
You probably recall how a couple of years ago Volvo Penta revolutionized inboard propulsion with the introduction of IPS. And how the Improved Propulsion System mates a state of the art inboard diesel with a pod drive that protrudes through the bottom of the hull.
A quick refresher on that technology: There are no propeller shafts or struts. Instead, twin counter rotating propellers on a drive leg face forward instead of aft. There is no rudder. The drive units articulate, actuated by either power steering or a joystick.Benefits include significantly better handling at all speeds, vastly improved fuel economy and a low noise signature.
First generation Volvo Penta IPS was only available in twin engine installations.Now Volvo Penta has introduced a four engine installation on the brand new Lazzara LSX Quad 75 express motor yacht. Its hull form was specifically engineered to take full advantage of IPS.
So naturally it follows the IPS Quad package boasts impressive top speed, strong acceleration, stellar fuel economy and enviable handling manners. The real eyebrow raiser is the way compact IPS Quad frees up what would have otherwise been engine compartment. Liberated space has been transformed into the crew's stateroom and a sixth head, effectively bestowing the Lazzara 75 with the interior space of about an 80-footer. Another plus, IPS shallow draft measures from 12- to 18-inches less than it would be with a traditional twin screw inboard.
Want performance numbers? The Lazzara LSX Quad 75 boasts a top speed of 35 knots. It cruises at 30. Lose one of the four engines and top speed drops to 27 knots, still an effective turn of speed. On two engines the boat runs 18 knots. Depending on engine rpm and sea conditions, and when compared to a conventional inboard, fuel economy improves by a whopping 40- to 50-percent. That's nearly double the range, 400 nautical miles at 31 knots, or 859 miles at 13 knots (minimum planing speed). Another noteworthy characteristic is the way IPS virtually eliminates engine noise and vibration, soot, smoke and fumes. It does so by burying exhaust under the boat. By the time it bubbles to the surface the boat is long gone.
Most tantalizing of all is the Lazzara's incredible maneuvering prowess. At cruising speed the steer by wire and IPS drives lends the feel of a 30-footer. At low speeds the joystick precisely swivels the drive legs, moving the boat in predictable increments. Inch forward, creep aft, or crab to all points of the compass. During testing near St. Petersburg, Florida, I was able to hover in place, useful when maintaining position off a fuel dock while waiting for your turn at the pumps. With no exaggeration docking is as easier as parallel parking a car. In fact, close quarters maneuvering is so nimble and precise an owner becomes supremely confident after about ten minutes practice. Clearly this is bad news for captains whose skills seem doomed to redundancy.