E-Pods and Docking

10/19/12

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E_Pods 3000 Low Speed Maneuverability on Pacific Dragon II

Low speed maneuvering to dock a sailboat with a single prop is from my experience the most difficult and dangerous activity associated with sailing.   More boat damage and injuries will occur during this than any other time. This is why the ASA Bareboat Cruising Coarse focuses more time on docking than anything else.   Charter companies are known to do the docking for the customers escorting them out/in the marinas to prevent the damage the boats would otherwise have to endure at the hands of inexperienced skippers.   Compared to most single screw monohulls the Gemini is a pleasure to dock.  However, it still is no great pleasure in a cross wind due to the large windage, light weight and minimal keels, she can easily get away from you.      

For low speed maneuvering the control provided by large twin counter rotating props provided by a solution like the E-Pod 3000 is undisputed.  Everyone envies the control demonstrated by any boat having a dual prop arrangement.  The counter rotation of the props allows you to back up or move forward without any prop-walk pushing the boat sideways.  In addition, by selectively using one prop or the other the prop-walk can easily be used to your advantage to move the boat sideways.  Reversing the trust between the two engines allows the boat to turn in place, which is by far the most useful advantage and makes the boat able to manage in tight spaces that would otherwise be completely off limits to the boat.  The electric drives also provide instant high thrust in forward or reverse having no transmission to shift.  Also for short bursts the E-Pod motors can produce far more thrust than any other solution available today.

Nothing concerns me more when going for a sail then that final 30 seconds of the day underway during the docking sequence.

Let me walk you through it so you get a better feel for how stressful it can be:

  1. Fenders are deployed on all sides to protect the boat,
  2. Dock lines are readied,
  3. Crew stands by to fend off at bow and stern,
  4. Boat is slowed to minimum headway with steerage (around 2 knots for the Gemini if any wind is blowing),
  5. Boat is lined up for entering berth (I have a straight shot in with over a 100 yards to line up in my marina; but the slip is only 16.5 feet wide so there is not a lot of space for error when you are 14 feet wide),
  6. Engine is shifted to neutral about 50 feet from the dock and final adjustments are made to line up; at this point you must commit to the docking or abandon the attempt and go around and try again,
  7. Just before the entering the boat is turned to line better up with the dock since typically you are crabbing in a bit sideways to compensate for the wind up to this point.
  8. Once the bow clears the end of the dock the boat is shifted into reverse and slowly power is added to bring her to a stop.  This is where if the drive leg pops up you must have a backup plan to stop before hitting. A crewman ready to stop the boat with a spring line from the bow is the best backup planůmy slip is 45 feet long to be wide enough for the Gemini so the crew has some time to stop her.
  9. If all goes well, the crew jumps off and by hand brings the boat into final position and secures the boat to the dock.  The engine is not stopped or disengaged until at least two dock lines are secured (one from the bow and one from the stern.)  Power is applied as needed to move the boat forward or backwards until the boat is properly positioned.

 How would this be different with the twin e-pod arrangement?  Using the berth I currently have, it would probably not change much.  However, I would be more likely to move to a better protected berth that was not as open to wind and waves and which requires a 90 degree turn into it further inside the marina.  Also, I would have the ability to control the speed much more precisely operating at speeds below the minimum 800 rpm of the diesel.   The typical docking would be more like this:  

    1. The first few steps are the same, fenders, lines and crew ready,
    2. The boat comes in a minimum speed well below 2 knots,
    3. I stop the boat just in front of the berth,
    4. Turn in place 90 degrees towards the berth,
    5. Slowly move forward into the berth adjusting the alignment as I move forward with the twin engines and prop-walk,
    6. The crew steps off the boat onto the dock and ties up.

The lack of an engine making noise and vibrating will greatly improve my communication with crew and people on the dock.  In fact, I feel the lack of noise will greatly reduce the sense of tension that always develops during docking maneuvers.  Anchoring and picking up a mooring would be similarly improved since you can turn and move forward or backwards at will.  I hope that the E-Pods once installed perform as well as I expect.

Update of experience in use:  The e-pods are as wonderful as I had hoped for docking; just as I had envisioned.  I currently am in a berth that requires a 90 degree turn; which only requires the reversal of one engine for a short time to turn the boat into the berth.  The operation is nearly silent and is slowly executed without any tension.  Even better in that I have no hesitation to do the maneuver alone which is a complete contrast from the diesel outdrive combo.

 

 

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