The Joy Stick Club
By now everyone who wasnt hiding out in a cave during the last boat-show season has heard of Beneteaus new Dock & Go drive system. Introduced on a new sailboat, the Sense 50, that was specifically designed to accommodate the system, Dock & Go wowed crowds at shows from Annapolis to Miami with its uncanny ability to spin a monohull like a top on a spindle and drive it sideways to a dock. With just two fingers on a simple joystick control, the helmsperson on a Dock & Go-equipped boat can perform feats of maneuverability that no twin-engine catamaran could ever hope to match.
Superficially, Beneteaus introduction of Dock & Go (sister company Jeanneau followed suit with an identical system called 360 Docking) seems to follow a tried and true script. An existing systems technology (in this case a rotating pod drive) that has been popular in the much larger powerboat market for years is finally introduced into the sailboat market and is hailed as an amazing breakthrough. For decades powerboaters have no doubt been laughing up their sleeves at us, making jokes about Luddite sailors who are forever behind the curve.
Except this time Beneteau actually did break virgin ground. Yes, powerboats have been available with rotating pod drives for some time. Most of these systems, however, involve twin pods that rotate less than 30 degrees in either direction. By swiveling two drive pods and driving their propellers in and out of reverse, manufacturers have produced powerboats with uncanny maneuvering ability that can be controlled with simple joysticks.
More recently, ZF Friedrichshafen, a major German manufacturer of both automotive and marine drive-train systems, has introduced a more advanced single-pod system (the ZF Marine 2800) with a pod that rotates 90 degrees to either side. Together with a bow-thruster, it can provide joystick maneuvering for powerboats with just one engine.
But Beneteaus Dock & Go (developed in partnership with ZF Marine) goes one better than this. Its drive leg (a modified Yanmar SD-50 saildrive) not only pivots through a full 360 degrees, but can do so in a fraction of a second. As such, it is the first fully rotating pod drive introduced into the recreational marine market. The only other fully rotating pods are found on commercial vessels, and these are very large systems where the propulsion motor also rotates with the drive leg.
From whence it came
Interestingly, Beneteau did not set out to invent Dock & Go. Instead, it sort of stumbled across it. According to Bruno Belmont, Beneteaus sailing development manager, the company was working on a hybrid diesel-electric system with a drive leg that could flip 180 degreesthe idea being that a forward-facing propeller that is spinning while a boat is sailing can create lots of regenerative power. After Beneteau and ZF developed the hybrid drive leg and realized how quickly it could shift position (less than a third of a second to turn through 180 degrees), a second development program for Dock & Go, with a diesel-powered leg, was also launched. The first D&G prototype was tested in 2009. (Meanwhile, the hybrid project has also been moving ahead and is now scheduled to come to market in 2012.)
Dock & Go is not the first joystick control system to be installed on a sailboat. German builder Hanse has been working with a system called ComfoDrive, which features a bow and stern thruster controlled by a single joystick, that it has tested on a prototype boat but has yet to bring to market. Dock & Go is, however, the first pod-drive system to be installed on a sailboat.
Like ComfoDrive, but unlike pod drives found on powerboats, Dock & Go is not a primary drive system, but is instead intended only for close-quarters maneuvering. Unlike ComfoDrive, however, Dock & Go does come into play every time a boat is put into reverse. Instead of the propeller running backwards to create reverse thrust, the drive leg flips around 180 degrees any time the helmsperson puts the engines throttle control in reverse while under power.
Only when Dock & Go is fully engaged does the joystick come into play. Now the drive-leg works together with both an autopilot and a bow thruster to control the boats bias. The autopilots only job, however, is to hold the rudder in place on centerline so the joystick can do its job. Engine rpms are limited to 2,000, but this is more than enough for the drive leg to push the stern of the boat around with authority while the thruster handles the bow.
The system does have significant limitations. For one thing, the drive leg, though it rotates fully, can only deliver thrust in four directionsahead, reverse, and side to side. Also, the bow thruster runs off a standard DC electric motor. Its thrust is not variable, and if asked to work too hard it quickly overheats and shuts down. (This last limitation has been overcome in powerboat installations that utilize both ZFs new 2800 pod drive and its new model 185 AC electric thruster, which has variable output and can run for 30 minutes continuously.)
And, of course, the system adds cost and complexity. According to Wayne Burdick, president of Beneteau USA, the cost of adding Dock & Go to a boat is roughly $15,000 (depending on the specific installation) over and above the added expense of an autopilot and bow thruster. And it remains to be seen how reliable they are. It seems likely that a fully electronic drive-by-wire system like Dock & Go will ultimately prove more reliable than mechanical systems, but when something does go wrong, very few boatowners will be able to troubleshoot problems on their own.
What the future holds
Currently Dock & Go is only available on larger Beneteau and Jeanneau models driven by 75hp Yanmar engines. According to both Burdick and Belmont, however, it should be available with smaller engines in the near future. Beneteaus immediate goal, they say, is get the system on many more boats and educate sailors as to its virtues.
In terms of refinements and variations, its easy to see several paths forward. After using the system myself (see Dock & Go In Action on pg. 46), I can easily see the system being used on smaller boats without bow thrusters. A drive leg that can deliver thrust in all directions is also one obvious improvement, as is mating it with thrusters that can run for extended periods (Vetus, for example, is reportedly set to introduce a cooler-running DC thruster in the next year or so). Presumably, it also wont be hard to engineer a function that allows a D&G-equipped boat to automatically maintain a constant speed and heading or even a stationary position, so a helmsperson can more easily hang fenders and deploy docklines when coming to a dock.
But Beneteaus Belmont is already looking beyond smaller tweaks like these. He envisions a day when D&G systems will have sensors for detecting the proximity of docks and other solid obstructions. Hes also talking about automatic docking, where a boat can sense the presence of an empty parking spot and put itself in it without human assistance. All this in furtherance of what Belmont claims is Beneteaus ultimate goal: making boats more and more user-friendly so more and more people can enjoy the sport of sailing.