Volvo Penta - Sterndrive Joystick
Volvo Penta Sterndrive Joystick
Volvo Penta first introduced intuitive joystick maneuvering to pleasure boats with their IPS system in 2005. For the first time a pleasure boats in the 31’ to 60’ (9.4 m to 18.2 m) range could independently vary the thrust angles of its props on pods to move a boat in any direction -- even straight sideways -- in response to the position of a single joystick at the helm (or at an additional docking station).
Volvo Penta applied this technology to its twin sterndrive propulsion packages in 2010, bringing joystick control to inland lakes and coastal areas dominated by sterndrive boats.
Intuitive Control. The joystick removes the disconnect between what the captain wants the boat to do versus the actual shift and steering wheel positions that accomplish the goal. Push the joystick in any direction and the boat moves that way. Rotate the joystick and the boat rotates. Or do both -- move and rotate -- simultaneously.
Replaces Bow Thrusters. The joystick replaces the purchase and upkeep of a bow thruster, and with just one control for all boat movements, it’s easier to use than a bow thruster. Bow thrusters also require their own battery and continuous use can over heat its motor and cause it to shut down. Further, bow thrusters typically have one setting which may not provide enough thrust in certain situations. Also, it is good to remember that a bow thruster can only move the boat to the left or right.
The basic principle of the sterndrive joystick is the same as this illustration for inboard IPS. With the starboard drive turned to starboard and in reverse and the port drive turned to port in forward, the boat moves directly to starboard.
By turning one sterndrive lower unit to port with forward thrust and turning the other to starboard with reverse thrust, a joystick system makes the boat go directly sideways to starboard, or vice-versa, even varying the sideways thrust based simply on how far the joystick is pushed. Varying angles and rpm can combine sideways thrust with movement forward or back, and even simultaneously rotate the boat along its keel.
Fly-by-Wire Reliability. There are more ways for mechanical shifts, throttles and steering to fail than when electronics control the engines and drives. Volvo Penta’s electronics include redundant components with built-in cross-checks and systems monitor themselves to catch problems. Independent control of each drive also means two independent steering systems -- redundancy not available with traditional hydraulic steering or cable steering which is typical in gas sterndrive boats.
Computer Intelligence. Tasks like synchronizing engines and maintaining constant rpm are all much easier with computerized throttles. (Most of these advantages come with electronic engines and controls, regardless of whether the joystick is also installed.)
Joystick-controlled sterndrives are now available powered by Volvo Penta diesels.
Retrofit and Availability. The basic sterndrive joystick system hasn’t changed much since Volvo Penta introduced it in 2010. But engine choices have expanded and Volvo Penta now offers the ability to retrofit a joystick in some instances.
Volvo Penta first introduced recreational boaters to intuitive joystick control in 2005.
In our experience, in docking situations have the option of swapping a pair of shift levers for a single joystick that makes a boat mimic joystick input is the single greatest feature of the system.
This is particularly true on sterndrives. Conventional inboards can be maneuvered with shifts alone by simply centering the rudders. Large propellers of inboards make boats respond to shift alone, without adding throttle. Maneuvering twin conventional sterndrives, on the other hand, often requires juggling two shifts, two throttles and the steering wheel.
Thought-free Shifting. For new boaters, many difficulties with docking stem from the disconnect between what they want the engines to do and the actual shift and throttle positions needed to make it happen. With traditional shift and throttle, human muscle memory developed over many, many times maneuvering a boat eventually makes shifting intuitive.
A joystick eliminates that learning curve both for new captains and those moving to a larger or different boat. Twist the joystick knob and the boat twists, putting one engine in forward and another in reverse with no muscle memory needed. Pull the joystick backward just a bit and both engines engage in reverse. Pull it farther back and both engines give more throttle in reverse.
Nuanced Control. Experienced boaters likely know, simply by feel, which engine is in what gear. For them, the nuanced control the joystick provides will likely be what is noticed when first maneuvering with a joystick. Pull the joystick back and twist it just a bit to ease a boat backward and subtly rotate it at the same time -- the basic maneuver required to back into most slips. Conventional sterndrives require coordination, timing and experience reading wind and current for that maneuver. The joystick eliminates years of practice and gets it right every time.
Fingertip control is all it takes. Engines respond to make a boat move in the direction the joystick is pushed, and both the joystick and the engines snap back to neutral at idle when the joystick is released.
Return to Neutral. Boats have three gears for each engine -- forward, reverse and neutral. Whether neophyte or old salt, it might be easy to tell when an engine is in forward or reverse, but sometimes neutral isn’t as obvious. It’s not uncommon to get a little momentum going and take an engine out of gear yet feel as if the boat is still in gear.
This is particularly true with today’s quiet engines, smooth-shifting transmissions and shift levers mounted on an inclined dash so neutral isn’t straight up toward the sky. But simply let go of the joystick and both engines snap to neutral at idle. Further, EVC controls beep when shifted into neutral. No looking down at levers. No guesswork.
Sideways thrust using just two engines and one joystick eliminates the purchase and upkeep of a bow thruster as well as a separate set of controls to operate the thruster and a separate battery system with a breaker usually located in the bow.
Sideways thrust over a boat length or more is really not used all that often in practical situations -- at least it shouldn’t be. Rather than muscle a boat sideways into a strong wind or current just because it can, it’s easier to approach most difficult docking situations conventionally. But there are occasions that moving a boat directly sideways is an enormous advantage.
Why Go Sideways? Boats simply aren’t designed to go sideways through the water. Volvo Penta’s joystick system accomplishes it quite effectively, but by using lots of horsepower to move any distance against even moderate wind. It’s much more graceful to power slowly up to the dock, bow into the wind or current, secure a bow line and gently pivot the stern into the dock.
In this situation, particularly if working against a strong breeze, consider using sideways thrust to move a few yards away from the dock and then pivot the stern out, away from the dock, and back into the wind.
Small Corrections. Sideways thrust is better employed to move the boat inches, not yards. If the wind blows the whole boat a little too far to one side of the slip -- difficult to correct with a bow thruster and nearly impossible to correct without -- give a joystick a tap to the side to simultaneously nudge both bow and stern back to windward, without ever stopping progress into the slip.
Tight Quarters. Another time sideways thrust becomes a game changer, in our opinion, is when traversing tight quarters. Think of a narrow marina with a quick current setting down toward that 40 footer (12.19 m) sticking way out of a 35-foot slip (usually with the gnarliest-looking anchor in the marina hanging beneath the pulpit). It’s a sticky situation for the best pro captains, but a joystick’s go-any-which-way ability mitigates concerns.
Safety Valve. Because the joystick moves a boat whichever way it is pushed, it quickly, and intuitively overcomes any docking situation gone wrong -- knowledge that is a confidence boost for any boater, seasoned or inexperienced.
CAN-bus wire connections allow simple installation of multiple controls and eliminates much of the possibility of failure of mechanical shift, throttle and steering systems.
Collectively, the captains at BoatTEST.com have many, many days at sea aboard anything from small outboards to 200 footers (60.96 m). We’ve all had shift, throttle or steering systems fail, both mechanical and electronic. The simple fact is that there is more to go wrong with mechanical systems than there is with electronics.
Volvo Penta’s shift and throttle electronics include built-in redundancy -- two independent control circuits in the helm and two position sensors in the steering cylinders. If a problem develops in shifts or throttles, for instance, self-monitoring computers will almost certainly catch it and return the engine to neutral and idle.
Mechanical shifts typically fail and stay in their last position -- even if it’s reverse while backing into a slip. (In fact, a broken traditional shift cable might push the transmission into one gear -- either forward or reverse -- but no longer pull the cable to disengage that gear. The only immediate remedy is to shut down that engine.)
Each lower unit has its own independent hydraulic ram that receives signals from the steering wheel or joystick. Hydraulic hoses are short, and the two independent rams provide get-home redundancy in case one fails.
Volvo Penta has designed two-sensor systems in the steering hydraulic system for fail-safe redundancy in each unit.
Twin Lower Unit Controls
Because joystick control hinges on a pair of sterndrives turning independently, Volvo Penta includes two independent hydraulic steering systems. Each sterndrive has its own hydraulic pump and one or more steering cylinders. If one sterndrive hydraulic steering system won’t work, the other system still provides steering for the ride home.
Compare that to conventional sterndrives and steering where both engines are connected to one hydraulic steering system. If it loses fluid or pressure neither engine will steer.
Short Hydraulic Hoses
Fly-by-wire steering also means the hydraulic systems are isolated to a small area right at the stern. Conventional systems rely on long hydraulic hoses or tubing runs affected by corrosion and vibration all the way from helm to transom. (Traditional hydraulic steering relies on the steering wheel, which is actually a human-powered hydraulic pump. Power steering only amplifies the hydraulic pressure cues from that steering wheel. Some redundancy comes with dual steering stations, duplicate power steering pumps and multiple steering cylinders, but all are connected to one hydraulic system. Failures, therefore, leave a boat without steering.)
Most gas-powered boats use power-assisted cable steering.
Volvo Penta’s Joystick Sterndrive system is more than just joystick docking. Electronic shifts, throttles and steering and intuitive information displays bring boating into the digital age.
But Does it Work?
As with anything else, the proof is in the pudding. Our test of the Joystick Sterndrive system showed that it indeed has the ability to allow for operations on a level that simply would not be possible, even from the most skilled captain in challenging situations.
In one of our tests, on the Joystick Sterndrive’s test boat at the Volvo Penta test facility in fact, we first did the basics. Away from the dock we ensured that the boat followed the maneuvers of the joystick as advertised. But this system is all about providing precision.
Where Precision Counts. So then we went to the dock and brought our test boat in both port and starboard side to. Again, no problems as the boat followed the actions of the joystick perfectly. And this in both a crosswind and cross current. But we still needed more convincing.
At left is the shift from the steering wheel, which converts circular motion into digital signals that are sent to the hydraulic actuators on each sterndrive unit, the throttle and gear-shifting sticks (in the middle) send direction input to the transmission and throttle settings to the engine, and at right the joystick unit translates the stick's motion into commands that go to all of the above locations -- all done by wire and software.
Our test captain moves the test boat easily between two other boats at a dock with one foot clearance both from and back.
Tight Fit.So to up the ante a bit, we brought two more boats in and laid them less than a foot off the bow and stern… clearly a situation with no margin for error. We pulled the test boat out with no hint of drifting into either of the “obstacle” boats, and then did the previously unimaginable… brought the test boat right back into the same space, with surgical precision. The system worked flawlessly.
How to Finesse
But there’s more to the finesse of this sort of precision than just moving the joystick. Remember that this is not a video game. Movement of the joystick directly translates to mechanical components continually being engaged. Just as we would never shove the engine controls into forward and reverse over and over again, we also should not treat the joystick roughly.
Gentle, light fingertip controls will be the key. Move the joystick slightly, let the boat respond, and then make corrections to that momentum. Captain Steve uses a “three moves” method of joystick docking. Try to put the transmissions into gear only three times as the dock is approached. That method will allow for a more gentle, and therefore comfortable type of approach, and it works. Try it.
Volvo Penta’s Joystick Sterndrive system brings with it the company’s Electronic Vessel Control, which is also available but not necessarily standard on other propulsion packages. This is more than just fly-by-wire shift and throttle. EVC integrates all engine information and allows it to be displayed on Volvo instrumentation as well as most third-party navigation displays.
Electronic Steering and Engine Control Ergonomics. Since the steering wheel and shift levers are just electronic interfaces, Volvo Penta engineers create the precise “feel” they’re after.
The exact amount of resistance required to turn the steering wheel and how far the sterndrives turn with each degree the steering wheel turns, for example, no longer require precise engineering to match hydraulic components to boats and engines. Instead, Volvo Penta engineers design the wheel with the desired resistance and then tell a computer chip exactly how to respond to steering wheel movement.
The same is true of shifts and throttles, which engineers designed to provide just the right snap into gear or back into neutral, just the right resistance to the lever when advancing throttle, and decides exactly how far the lever is moved to shift the boat into gear and accelerate. (Changing any one of these variables on mechanical shifts will alter the others. Decreasing resistance, for example, usually increases the lever travel -- which is set by SAE standards -- needed to shift an engine into and out of gear, and that resistance might change as cables age.)
A Few Other EVC Benefits. With EVC, captains monitor engine trim or set the computer to automatically trim engines for ideal performance. One lever can control both engines at the captain's option. Engines automatically synchronize rpm when already close.
One Button Adjusts Throttle Up or Down by Increments of 50 rpm. With each rpm or trim change, EVC shows the change right alongside the chart plotter’s ETA to the destination. The list goes on.
Multiple Displays. Volvo Penta facilitates mounting the company’s EVC displays in as many as six locations aboard. Each display allows several preset screens with significant yet simple user customization.
EVC information also shares with any chartplotter, radar or other equipment compatible with the NMEA 2000 standard.
Volvo Penta’s Glass Cockpit touchscreen displays include two-finger pinch or spread to zoom out or in.
Compatible with Volvo Penta’s Glass Cockpit. Volvo Penta’s new Glass Cockpit System allows the captain to choose what information to show and where to show it on one or several of Volvo’s 8” to 19” diagonal touchscreen displays. Change displays at will to suit the task at hand, and even zoom in for a closer look at one part of a display just by spreading two fingers apart on the screen. A line of displays that are not touch screen are also available.
CAN-bus. An electronic backbone interconnects everything -- throttles, steering and displays -- simply by attaching each component to that backbone. This simplifies installation and integration of additional equipment, for example another set of controls in the cockpit of a fishing boat or the ability to view engine information on a screen elsewhere in the boat.
Volvo Penta Joystick Sterndrives are available on gas engines from 270-hp to 430-hp.
Joystick control is available on sterndrive diesels up to 400-hp.
Retrofit and Availability
When we first reported on Volvo Penta’s Joystick Sterndrive in 2010 it was available only when a boat was first built and only on gas engines from 270 through 430 horsepower.
Volvo Penta has since made joystick control available on diesel-powered sterndrives from 140 to 400-hp.
Joystick control can also be added to many vessels built with the EVC system but without joystick control when built. EVC engines with or without joystick control can also now be retrofitted to existing boats that have electronic steering. (One caveat to adding joystick controls -- many boats are now built with drives farther apart to add clearance between drives and also increase a boat’s response to joysticks input.)
Differences Between IPS and Joystick Sterndrive
New Software Joystick Sterndrive isn’t an adaptation of IPS. Volvo Penta developed new software for the sterndrive system. The concept is the same, but getting a boat to respond predictably to a joystick by using two sterndrives mounted close together abaft the transom is much different than getting an inboard boat to respond by using drives tucked underneath, much closer to a boat’s natural pivot point.
With Volvo Penta's system the throttle and gear sticks must be in neutral in order to activate the joystick system which requires that the "Docking" button on the base of the unit be pushed (left). This is an important safety feature and means that the joystick will not be accidentally engaged. When more docking power is needed, the button at right can be pushed which raises the engines' rpm from 1750 to 2150 (right).
The following features, benefits and insights are also worth noting:
Drive Differences. Other than being individually steered, joystick sterndrives are identical to conventional drives.
Progressive Throttle and Two Throttle Modes. Pushing or rotating the joystick just a little corresponds to small corrections and subtle boat movements. Pushing or rotating the joystick further increases a boat’s response.
In normal docking mode, engine throttles are limited to around 1750 rpm. Volvo Penta includes a higher-power mode, too. Pressing this button limits engines to around 2150 rpm.
Joystick sterndrives include traditional sterndrive benefits like Volvo Penta’s DuoProp, which employs a pair of contra-rotating propellers on each drive to eliminate rotational torque and propeller side force and also markedly increase propeller efficiency.
In some ways, joystick docking benefits sterndrives more so than inboards.
At first blush, joystick docking seems like it most benefits bigger boats. In fact, the basic concept was developed first for harbor tugs, research ships and oil platform service vessels.
But large boats move more slowly and predictably, and are often less affected by wind than typical 30 or 40-foot (9.14 m to 12.19 m) sterndrive boats.
Sterndrive boats actually require more user input when docking - shifts, throttles and steering than do much larger inboard-powered boats. In our opinion, this makes joystick control even more useful for sterndrives than for inboards.
For boaters on the fence as to the extra cost of joystick docking, sea trial a boat with and another without joystick control. If joystick control will ease stress when docking at the end of an otherwise perfect day, or open up new cruising destinations with the confidence of handling any docking situation or allow a spouse or kids to join in helping to dock, the choice seems pretty clear.