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IPS: The brain behind the joystick

Volvo’s rapid-fire advances in diesel engine management and system integration enable a skipper to precisely maneuver a 75-foot boat with the lipstick tube-sized control

Volvo’s rapid-fire advances in diesel engine management and system integration enable a skipper to precisely maneuver a 75-foot boat with the lipstick tube-sized control

Almost two years ago to the day that I was in Spain for the unveiling of Volvo Penta’s breakthrough Inboard Performance System, I found myself at the Tampa, Fla., home of Lazzara Yachts, who along with Volvo promised an introduction to “The Next Generation of Yachting.”

Behind a huge black curtain we were to find an abundance of new technology, beginning with the elegant Lazzara LSX Quad, a new 75-foot express cruiser designed around and powered by four Volvo IPS 600s, the steerable pod drive system that is installed through the bottom of the hull and features forward-facing propellers.

Positioned four abreast, this new quartet of higher-output IPS units is controlled by Volvo’s latest marvel, the IPS joystick.

Were we looking at a “new generation” of boat and propulsion as Volvo and Lazzara trumpeted? Let me put it this way: It doesn’t take a crystal ball to predict that this technology has a real future.

Just a few years ago many of us would have considered the idea of operating a four-engine, 75-foot yacht with a single joystick a long shot. But the rapid advancement in diesel engine management, on-board system integration, and Volvo’s IPS, including “steer by wire” technology, turned a futuristic concept into reality.

The benefits of the IPS include better handling, fuel economy and performance and less noise and emissions. Lazzara engineers say the system is easy to install, taking just seven hours for the entire four-unit setup, considerably faster than a conventional installation.

And the new joystick control significantly enhances the yacht’s user-friendly close-quarters maneuvering. When properly set up, the joystick provides intuitive, logical one-hand maneuvering below planing speed.

Of course, the traditional helm station still exists, including the steering wheel, and shift and throttle levers, which remain the primary vessel controls in open water. Communication between the helm, joystick, instrumentation and the IPS drive units is integrated through the Electronic Vessel Control system using a serial data bus cable and CAN bus protocol, which makes incorporating additional joysticks a relatively simple task.

As I discovered first-hand in sea trials off St. Petersburg, typical joystick operation is simple and intuitive enough for any child who plays video games, and even for those of us adults who don’t. Once the engines are started, you enable the joystick by simply pressing a button on the unit, after which there is an audible “beep” to confirm that control has been transferred from the conventional helm to the joystick. The joystick integrates various safety features, such as quickly returning to the neutral position if the stick is released, automatically disengaging control if the conventional throttle levers are operated, and on a vessel with multiple joysticks, only one location can be enabled at a time.

Time after time, I watched the IPS drive units perform intricately choreographed maneuvers based on the joystick position. Here’s how simple it is: to move the boat sideways, diagonally, forward or reverse, for example, simply push the joystick in that direction and the vessel moves accordingly. The farther you move the stick, the greater the vessel response. Bow and stern thrusters aren’t needed with the joystick, as rotating the knob on top of the stick pivots the vessel in either direction.

Lazzara Yachts president Dick Lazzara was in high spirits and not the least bit nervous as he pointed me to the cockpit-mounted joystick and suggested I spend a few moments familiarizing myself with the movement of his new 75-footer before getting too close to the cement pilings. A few moments were all I needed to be comfortable with the yacht’s operation, even though I couldn’t see most of the vessel’s port side from my position. The joystick had a very positive feel, and the LSX reacted immediately to any input, and in a very predictable manner.

Lennart Arvidsson, Volvo chief engineer on IPS, explained how critical setting up and programming the joystick movement is to the smooth vessel operation I experienced. “There needs to be an immediate and predictable response to any joystick movement for the operator to feel confident and not become overzealous, causing unsettling vessel movement,” Arvidsson says.

My decision to back down toward the fairway seemed fine with Lazzara, so off we went. Moving the stick back, the yacht made sternway, and when the current began pushing the boat to port, slight movement of the joystick to the right had the boat moving to starboard. The winds made the bow drift to port, but slowly rotating the knob clockwise brought it back. I found myself maneuvering a 75-footer with more confidence and considerably less effort than my 36-foot, bow-thruster-equipped trawler requires. Maneuvering with the joystick doesn’t involve the same coordination of steering, throttle, transmission and bow/stern thruster required at a conventional helm. Instead, simply move the stick or rotate the knob in the direction you need to go: intuitive, one-handed, single-lever operation.

There are two speed settings that can be changed by the operator by simply pressing a button. The settings, high and low, control the maximum engine rpm that will be available to the joystick. Although I didn’t use the high setting, I think it would be helpful in situations of stronger current and wind. The value for these settings is determined during predelivery setup, based on the vessel design parameters. On the LSX, for example, low speed was set at 1,430 rpm, the high speed at 2,000 rpm.

In addition, the boatbuilder selects one of three steering settings that determines how hard a turn the vessel will make. Arvidsson said the Lazzara was set for the most aggressive turning available with the system. The joystick also is fine-tuned by Volvo technicians during initial setup so the boat moves accurately in response to the commands, eliminating any crabbing. These settings are all made using the Volvo Penta VODIA tool, a PDA-based device that communicates with the system’s on board database. The same tool is used by Volvo technicians to troubleshoot the system or upgrade software.

As advanced as it is, the joystick is only part of the system. IPS, remember, is a complete package that includes everything from the steering wheel, controls and instrumentation to the engine, drive unit and propellers. IPS typically offers such benefits as higher speed, quicker acceleration, better fuel economy and handling, less noise, and reduced emissions. The Lazzara LSX Quad, for instance, has a full-turn radius of 187 meters versus 436 meters for conventional inboards, according to Volvo. Along with the existing 400 and 500 IPS models, Volvo has added the new IPS 350, based on the D4-260 engine, and the IPS 600, with its D6-435 diesel, both benefiting from the addition of compressors to the turbocharged/intercooled engines.

The Volvo system begins with the propulsion unit, which resembles a conventional sterndrive or outboard lower gearcase. The drives are installed through the bottom of the hull in specially designed structures integrated into the hull during the vessel’s manufacturing process. The lower units mate with the transmission and steering assemblies, which are installed from inside the hull, and the components are secured to the mounting collar with a locking flange. Watertight integrity is achieved with two substantial captive O-rings.

The drives are mounted slightly forward of the transom, coupled to the inboard diesels with short shafts and electronically controlled from the helm or joystick location. Combining the IPS drives with softly mounted engines is extremely effective at minimizing transmitted vibrations throughout the vessel. The drive units feature twin forward-facing, counter-rotating propellers. This unique design results in high efficiency, as the props function in undisturbed water and thrust is parallel with the bottom of the boat, unlike conventional inboards that tend to push the bow down due to the thrust angle of the shaft.

The LSX Quad’s four IPS 600 units are mounted athwartships, eliminating at least 10 feet of machinery space, which allowed for the creation of a full crew’s stateroom and sixth head. Arvidsson says the engines Volvo is installing in twin, triple or quadruple configurations are identical to each other and carry the same part numbers, including the drives. Volvo needs only to alter the gear ratio of the drives depending on the final power required.

The IPS 600 runs a 1.82 gear ratio, the IPS 500 a 1.94, while all other drive components remain the same. All IPS units use T Series props, allowing Volvo to tailor systems to each builder’s requirements based on vessel size and desired speed. For example, a fast 42-foot sportfisherman may run twin IPS 600s with T8 props, while the LSX Quad runs four IPS 600s with T4 props. Standardization not only helps with installations, but service centers don’t need to carry multiple inventories for different vessels. And technicians can work on the 75-foot LSX with the same parts and tools and with the same training as an IPS-equipped 35-foot sportfishing boat.

The main difference between twin, triple and quadruple installations is in the software controlling the engines and the interface between the skipper and the IPS. The vessel operator would control a twin installation boat in the same manner as the LSX Quad. With the LSX installation, the engines are paired port and starboard, with the outer engine on each side operating as the slave to its inner companion. Although single-screw vessels of all sizes have their proponents, you can’t dismiss the enhanced maneuverability and safety of redundant systems that multiple engines offer.

The LSX 75 can sustain a 35-knot top speed with all four engines, according to the builder, which alone is news-worthy. However, she reached 27 knots on three engines, 18 knots on two engines and had ample power to steer and navigate on a single engine. In a demonstration, we viewed acceleration runs with four, three and two engines. All were impressive in terms of performance, but most interesting to me was the fact that at no time did the vessel’s handling seem affected by the loss of a propulsion unit or two.

Standing on the pier and watching the acceleration runs from a standing start, a few other things were apparent, in particular the lack of bow rise during maximum acceleration. Combining the IPS horizontal thrust with the Lazzara hull form is an effective combination; the vessel planes at 12 knots. Also apparent was the absence of exhaust smoke, due in part to the combination of electronically controlled engine management and the below-the-waterline exhaust. And it took a few moments to realize just how quiet the 75-footer was; the only sound that could be heard from the pier was the water rushing past the hull of the LSX … and a few gulls.

Maintenance of the IPS drives is relatively simple, and the first scheduled service for lubricant change is at 400 hours. Zinc replacement is suggested annually, and antifouling applied on the bronze drives is as local conditions dictate.

Volvo has done an impressive job of integrating the quad IPS installation aboard the LSX with its joystick control. Having operated IPS boats of varying length and configurations, I can attest that the joystick further enhances the experience.