Dynamic Positioning on yachts?

You will find that many yachts that say they have DP1 Capability do not actually have any official notation or certification as such, it is just the ability to hold position.

DP 2 and 3 are for serious operators and operations hence the extra equipment, space for it and costs of operating it that these classed vessels incur.

Your statement above is what I was replying to. Plenty DP-1 yachts under the 3,000 ton mark as the OP's 1600 domestic is a 3,000 ITC ticket.

I realize that this thread is really about the more sophisticated systems but some who are unfamiliar with these smaller systems may find the details interesting.
On Mercury's Vessel View, which is the data display on Zeus (and many Mercury) equipped boats, there is a Skyhook screen that, when Skyhook is engaged, shows engine speed, heading and an icon which shows the yaw of the boat relative to its position when Skyhook was initially engaged. The change shown in the crosshairs is relative to the position error reported by the GPS. It's a fascinating screen to watch in strong winds and/or current while the drives do their thing to hold station. My last boat had Skyhook and, in my opinion, it's everything it's cracked up to be.

This was pretty clearly a calm moment...

Volvo's is pretty much the same as Skyhook in function.

From their website under mechanical on the 54:

"Volvo IPS II 900 series engines with pods, ACP and DPS features"

That's a nice compact basic DP-1 system. It gives the user of a small craft all the info needed. The definition of dynamic positioning is a computer controlled system to automatically maintain a vessel's position and heading by integrating the control of vessel propellers, rudders & thrusters. This system seems to do just that. Commercial operators such as drill ships and offshore rigs & platform supply vessels use multiples of equipment for redundancy, DP-2 is two complete autonomous systems of controls. thrusters, prime movers etc. DP-3 and so on.

You do NOT want to use skyhook in your slip. It keeps the boat within 1 boat length or around 50' and sometimes does some strong corrections......it will wreck the you know what out of the side of your boat if you use it in the slip.

You can get it on IPS, but it's optional. The boat I'm delivering and sitting on right this minute has Volvo IPS and the skyhook feature. I think it's standard with ZEUS.

Hmm, Dad's Sabre staid put pretty well within a foot.....

"Pretty well" doesn't work within a slip. On more advanced systems you can adjust the size of area and the frequency of adjustment.

Your position holding is only as good as the GPS unit that is integrated into the DP system. Civilian DGPS -SPS has an error of 3 meters or less. Military or science /survey GPS is known as PPS -DGPS or Kinematic DGPS & has no error or offset as it eliminates the ionospheres arc interference with L2 so I would venture to say that even the best of civilian DGPS units would have you knocking about in your's or your neighbors slip.

+1. It is spectacular for standing off at a fuel dock at an appropriate distance, waiting out a bridge opening and virtually anytime you need to hold station when proper safety considerations are taken. But I would never use it in close quarters. Like Auto Pilot for some, it is a license to be stupid or unsafe. But make no mistake about it, the boat is under power and while I know people use it as a tool for securing lines and fenders near a dock when single-handling, I would no sooner leave the helm unattended with Skyhook engaged than I would with AP.

And yes, Skyhook is standard with Zeus.

July 4, NYC. Macy's Fireworks. You head to a viewing section on the East River a couple of hours before the fireworks. You have to stay in that section throughout the entire display and until told you can pull out, a total of several hours. You're happy for DPS.

Now commercial ships have much different uses for it and have far more capabilities in their systems. Drilling ships, Cranes, Surveys, Supply ships for oil wells, pipe laying, cable laying, dredging. They don't just use it to stay in place, but to cover a specific pattern. I'll bet the ships searching for El Faro had DPS.

If you want to get tremendous control and precision on maintaining position, that will add to the wear on the thrusters and increase your power usage. During calm conditions you can go to a relaxed level of control and use your equipment more smoothly. The most advanced systems don't just deal with where you are but they look at the current and the wind and forecast what your position will be. Triple systems can have one or two on standby or keep all active and allow them to "vote". If one or two fails, then the others carry on while you repair the one that failed.

Simulation came up in another thread. One does much of their initial training in a simulation setting. To obtain a certification one must have a combination of training and of watchkeeping with DPS. There is a very rigid structure of the requirements for certification and I don't think anyone would today get certified if working only on a recreational vessel.

Yes, I see where a "blip" in the GPS position would result in some "unintended movement".

Duly noted and filed.

That said, the chance of running into a Skyhook system on an early 80's Hatteras are probably slim to none.

None. Zero. However, a DPS system could be retrofitted to it. Skyhook is Mercury only so primarily Zeus, but other DPS systems available. For a 50' thought I doubt one would ever want to do it.

I suspect the cost would be prohibitive. If I were to splurge I'd install a remote for engine/thruster control.

I suspect that that post is very important to the threads original intent.

For most yachts dynamic positioning is probably more about holding position for the best view during a meal, or just to feel like their feet are on the ground for a bit. With most people using such systems not bothering to register them, they probably don't feel the need to hire crew who are certified to run them either.

If you are on a serious working ship and the dynamic positioning goes out, you may have to scratch the fixture and head back for repairs. If you are on a pleasure cruise and the DP isn't working, it's just like any other toy going down.

We're obviously talking about many different levels of systems in spite of similar terminology. Skyhook and Volvo do refer to their systems as dynamic positioning and in a generic form they are. However, those who manufacture certified systems call their limited functionality "Position Mooring Systems". But they're great tools for many boats and very good for what they do.

I can't imagine going beyond DP1 on a recreational boat 200' or under. I'm sure some have. DP2 and DP3 are for mission critical work. A small yacht can just go back to doing things the old way if their system fails. To be a DP1, 2 or 3 it must be approved from class. You can have all the equipment but it not be class approved and it's often referred to as a DP0. Also, if seeking certification as an operator, a system can have all the equipment but if it's not been approved then using it doesn't count as time. The majority of systems sold for commercial use are DP2.

I think for the recreational boater, Mercury and Volvo opened the doors to what their systems could do. Just as their joysticks led to a much higher prevalence of joysticks in other larger boats, I think you'll see the same on simplified or limited functionality DPS. I don't think it will be classed systems, DP1, 2 or 3. Simply a recreational system. The primary use will be just holding position.

Thanks. I was referring to their DPS. Did the Cape Horns just have the z drive thrusters or also have DPS?