Convenient is as Convenient Does
I love technology, and the more of it, the better. Why let the wind blow you around the bay when a motor will get you there better? I came to my nautical maturity as marine technology for the general public was just coming into its adolescence. We used to mark fishing spots by lining up shore features with the compass and triangulating to get back to the same spot. When Loran C came out, it was a godsend. We followed two lines of numbers and maneuvered the boat to get the numbers we wanted to come up in the display. Then it evolved to actually do the navigating for us. How cool! Now we were steaming an hour in dense fog right to a Clorox bottle we'd left the day before. Then the range increased when GPS came along.
As boat handlers, we were revered. We commercial operators had a gift of how to handle our boats regardless of crowded docks and strong winds and tide. Then pods and joysticks came along that turned wannabe's into pros overnight. And it's all good.
Digital controls changed everything, too. By using 1's and 0's to control our engines and steering, manufacturers were then able to add a whole host of features that could work in conjunction with programming. And suddenly, at the push of a button, we have single lever controls of multiple engines, engines synchronizing themselves, troll-mode to slow them down, boats that trim themselves, and cruise control to keep their speed and make minor adjustments. And it's all good.
Computers are Taking Over
Because we are now using computers to control our boats, we can come up with a lot of ideas on how we feed information to those computers to get our boats to respond. In Volvo Penta's world, that computer control is called EVC or Electronic Vessel Control. We've reviewed the choices that EVC can present so be sure to watch it.
Now Volvo Penta has gone one better and developed a system that uses a sophisticated GPS antenna to present information to the EVC system in order to tell the boat exactly where it is… and keep it there. It's called DPS or Dynamic Positioning System, and I'm a big fan.
The ABC's of DPS
First of all, the concept isn't new, it's just been out of reach for folks like us. The Volvo Penta system is elegant in its simplicity, at least from an operator's perspective. You need some key components that people are more often getting on their boats anyway - namely, the IPS system of pods, the joystick, EVC, and Volvo Penta's 7" (17.8 cm) display. Then adding DPS is as easy as checking a box on the options list.
The DPS button resides on the joystick so there are no additional cutouts necessary in the panel. the "Docking " button is just below, and to the right of that is the "Hi-Power" button.
To activate the system, first you need to activate the joystick. You do that in just the same manner as if you were coming in to the dock, by pressing the "Docking" button. Now you're joystick is controlling the pods via EVC. One more button lies just above, and it looks like a target. That's the DPS button. Press it and sit back and relax as now your boat is holding position by itself. To disengage, press the button again, or move one of the controls. This is just the same as disengaging the joystick system.
Does it Work?
I positioned my test boat in front of a daymark at the south end of the Chesapeake. This gave a much better visual reference than saying "it works" in open water. Without the system engaged, I could easily see that wind and tide were moving us at .6 mph to starboard. I engaged the DPS and instantly, the speed over the bottom went to zero, and a glance out the windshield confirmed what I already knew. We were holding position perfectly. But because the system uses twin GPS receivers, not only is it very accurate, it also holds your heading.
As for the 7" (17.8 cm) display, that plays a part too. This is the same display that gives you your readout of the engines, fuel flow, etc, and we've covered it in the EVC video as well. Here, as the system engages, a warning shows on the screen and then a graphic that shows a boat in the middle of a compass rose, and an arrow showing the direction of the thrust that is holding you in position and at a constant heading.
Volvo Penta's 7" (17.8 cm) display is programmable to customize the information you see on the boat's operational parameters. That display is overridden by the DPS screen when engaged. You can see the display of a boat in the compass rose, with an arrow showing the direction of the thrust. In this case, the system was thrusting to port to counter the wind and tide trying to move us to starboard.
At the bottom of the display, the lawyers mandated that safety icons remain in display to alert you to the dangers of swimming around the boat while the system is engaged, and they're well received. I could easily see someone watching the movie "The Abyss" which shows how a research boat is holding position over a deep sea mining rig with just computer control, and thinking that their little boat can do the same over a small dive wreck. Not a good idea at all. The pods are working, the props are turning, now is not a time for being in the water.
But How Good Is It?
…Pretty darn good as a matter of fact. I wasn't content to let Volvo Penta off the hook just yet, so I asked myself: Is it accurate enough so that I could dock this boat single-handed, and then tie it up?
Before I even attempted such a thing, my safety consciousness said no! The DPS was not made to allow you to step off a boat with the drive system engaged. That's neither safe, nor smart boating. But you could. So to see just how easily you could, I went to the dock and slid my 36' (11 m) test boat into a slip. Then I engaged the system once again.
Sure enough it held our position, but now we had dock on all sides so the margin of error was more visible. Now I could see that we were moving around slightly, with a margin of error of about 2' (.6m) at the most, but averaging about 1' (.3m). We would gently move to the dock, bump against, and then ease away, and then ease back again. So yes, while I could have stepped off and worked the lines, I would choose not to.
So When Would I Use It?
So much for when I wouldn't use it. As for when I would, well I've already used it in a lot of situations, but most notably, when waiting for a bridge to open, waiting for a gas dock to clear and just times in general when the camera boat isn't ready and I need to adjust my test gear while waiting.
So I say let technology keep coming. If features like EVC, IPS and DPS are the result, then no one loses.