Bamboo, if your questions reflect your boat (multihull with large patio-door type entrance into the cabin
from the cockpit), a series drogue is IMO definitely not for you.
To review the three drag device types, how they are intended to work and their basic physical make-up, I'd encourage you to read Victor Shane's Drag Device Data Base (4th Ed or later). More importantly, it is loaded with documented cases where all the different devices have been deployed, in the real world, on multis and monos of all different sizes.
When this topic is discussed, I get the impression we're all talking about our favorite color; we talk as tho' we're exercising a personal preference for how we want to handle storm seas. Drogues e.g. are discussed by brand rather than by category or intended use. That's why I encourage folks to read DDDB and perhaps Earl Hinz book on this subject. (Oceanography & Seamanship by VanDorn would also be worth the time some selective reading would require). The referral to the USCG study and David Jordan's work is sometimes so absolute and exclusive as to suggest that's all one needs to know. IMO here is at least some of what's missing in this discussion - and in most discussions on this topic - that needs to be considered by Bamboo. I'm using Shane's conceptual terminology...
No-Pull Device - the typical parachute sea anchor
, deployed off the bow; a space hog to stow; physically extremely demanding to deploy; very difficult and time consuming to retrieve, and only after seas have significantly moderated (which as we know is subsequent to the winds dropping); intended to restrict boat movement to leeward (the 'anchor' piece); imparting large 'bungee jumping' forces on the boat (the seas will force something to move and the chute is unwilling, so the force of the water as felt by the hull
is accommodated by the rode
- thus, the sudden surging as tho' at the end of a bungee cord); subject to subsurface currents (a sistership to WHOOSH had to cut hers away after it was caught in a current
that took the chute straight down - it was a cold water eddy - depressing the bows into the sea)
Medium Pull Device - the series drogue; deployed off the stern; the heavier the boat, the more difficult stowage becomes (a Tashiba 40 we know has a series drogue bag the same size as their #1 genoa
bag; where do you stow something like that, given it will be the least likely used item in the boat?); relatively easy to deploy but difficult to retrieve until conditions moderate; designed to bring the boat to a near-standstill inbetween wave strikes, being pulled thru the water only when the yacht gets struck by a breaking wave, and so subject to significant 'bungee jumping' (Jordan recommends being seated with retraining straps in place, as e.g. what pilot boats and rescue
craft use); boat's aft end (transom, aft cabin
trunk if a center cockpit
design, and/or companionway
all need to be physically able to withstand wave loading); number of drogue units critically important when built but the whole device works acceptably with some drogue units coming out of the water due to wave train action, so monitoring usually required only for chafe.
Low-Pull Device - the Galerider is one such device; deployed off the stern; smaller size and weight makes stowage less of an issue; not intended to prevent drift to leeward, but rather designed to be used underway (very compatiable with windvanes & a/p's); rode
length adjustment appears more critical to effectiveness, so this may need monitoring & adjustment; more easily retrieved in higher winds/seas that the other devices; a variety of functionally similar products (of different designs) available on the market
IME most full-time cruising boats are sailed by short-handed crews, and a majority of those crews consist of middle-aged and older men
& women. When it comes times to move from theory to practice WRT choosing a drag device, I would think we should start there. The physical capabilities of the crew will determine what can be unstowed and deployed (and hopefully retrieved) effectively, which in turn will mean its use is more likely, and in addition how well a watch is kept and rode monitored & adjusted as necessary when deployed. From there, consideration of the boat's design, structural integrity and deck hardware
could be considered...and finally, the kinds of waters in which the cruising is to be done, as that will shape the kinds of conditions when a device will be deployed. IMO it's at that point when you can begin picking your favorite color... <g>