Zanshin I Jordan Series Drogue

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Jordan Series Drogue Here is the beginning of the construction process of the Jordan Series Drogue. The main line eyes have been spliced and now the 132 little parachutes need to be slipped over the line and sewn into place, one per meter.
Jordan Series Drogue
Jordan Series Drogue The main portion of the Jordan Series Drogue is complete in this picture, with the line flaked and banded with rubber bands so that it holds together and doesn't get tangled during deployment.
Jordan Series Drogue

While Zanshin I has a smaller sea anchor for storm use, I wanted something a bit more substantial in hand just in case I made a serious error in judging meteorological conditions and ended up in a storm which I could no longer handle. There are two main schools of thought in heavy weather tactics and each camp has it's adherents and detractors.
One camp advocates deploying a sea anchor off the bow; this sea anchor is essentially a parachute that unfolds underwater. Since water is much denser than air and has a high viscosity the parachute doesn't just slow the boat down in the same fashion as a parachute in the air keeps a jumper from plummeting towards the ground at an acceleration of 9.8m/s until terminal velocity (or the ground) is reached; what happens is that a hydrostatic lock is achieved and the boat will be “anchored” to a spot in the sea almost as if it had an anchor in the ground. This method of weathering storms has the advantage that the bow is pointed into the wind and weather and waves and that is what the bow is meant to handle.
The other school prefers to use drag devices from the stern of the boat and to slowly “run” from the weather. One of the great dangers of running from a storm, even under bare poles with no sails up, is that the wind is so strong that it pushes the boat along at great speed, which sounds good until you start running down a large wave and then hitting the trough, when the boat is too fast it tends to keep on going straight into the next wave instead of riding up the wave slope. Drogues and other drag devices prevent the boat from going too fast but don't go to the extreme of using a big parachute to stop the boat completely.
The sea anchor has a great advantage when there isn't a great amount of sea room since it keeps the boat drift down below one knot. But, just as when at anchor to the ground, the boat tends to swing left and right quite a bit even in the strong winds that invariably accompany storms strong enough to warrant these extreme measures. Thus the broadsides of the boat are frequently presented to the incoming seas and this makes for an uncomfortable ride below decks and can be dangerous when the seas are breaking.
Drogue systems have the advantage that the stresses on the boat from the braking system are lower and that the hull is never presented broadside-on to the seas. The rate of drift is much higher than with a sea anchor.

Jordan Series Drogue Here I went a bit overboard in splicing in metal eyes and whipping the end of the line for the Jordan Series Drogue on Zanshin I
Jordan Series Drogue
Jordan Series Drogue The drogue in it's special Peli Case. The heavy stainless bolts still need to be attached to the aft portion of Zanshin I
Jordan Series Drogue

Breaking seas are dangerous to boats of all sizes, the rough formula is if the height of the breaking wave exceeds 35% of the hull length (LOA) then a capsize can occur and no tested yachts (in “Heavy Weather Sailing” by K. Adlard Coles and Peter Bruce) managed to consistently resist capsize at 55%. Thus, Zanshin I could theoretically resist a 17.5 foot breaking wave beam-on without rolling but not necessarily any waves higher than that.
I opted to make a Jordan Series Drogue for use when the conditions get so bad that all I can do is go below decks and wait it out.
The Jordan Series drogue is, as with all efficient emergency systems, a basically simple device to deploy and use. It is a long warp to which many (in my case, 132) small parachutes are attached every meter. Taken together, they generate a huge amount of drag but not total hydrostatic lock. Even in breaking wave conditions only a few of them will collapse but the rest remain working and overall the drag is consistant yet there is enough give in the system to prevent very large shock loading to be transmitted to the boat.

Online instructions can be found out at Drogue making Instructions
Downloadable Manuals page - Jordan Series Drogue Manuals

3816 views since 2017-02-04, page last modified on 2017-02-19.