Jordan Series Drogue

Jordan Series Drogue parts

Tail portion

While Zanshin 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 an incompressible fluid 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.
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 could resist a 17.5 foot breaking wave beam-on 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, at heart a simple device. It is a long warp to which many (in my case, 132) small parachutes are attached every couple of centimeters. Taken together, they generate a huge amount of drag but not total hydrostatic lock. Even in breaking wave conditions only a few of them can collapse but the rest remain working.
Instructions at Drogue making Instructions