|
Speed-limiting
Drogue | Uses for Drogues | Design
and Construction | Sizes We are pleased to provide the following information to assist seafarers from around the world. However, neither Safety at Sea (Australasia)Pty Ltd nor its agents will have any responsibility or liability for any inaccuracies, falsehoods or errors in the information. For further information please see our disclaimer notice. The proper use of
a Sea Anchor off the bow should not be confused with the proper use of
a Sailors planning extensive offshore passages should purchase a copy of the Drag Device Data Base (available from Safety at Sea) with a view towards more in depth study of the different applications of both devices. A speed-limiting Drogue is towed off the stern. It's purpose is to limit the boat's speed, reduce her angle of yaw and to provide for steering assist in strong following seas. You can, and may have
to, steer the boat with the Drogue in tow. There is a "Catch 22"
with any speed limiting Drogue: The same low pull that allows for steering
control may also allow the boat to broach, capsize and/or pitchpole in
the heaviest seas. The above notwithstanding, speed-limiting Drogues can be of immense value in strong following seas and have been used to stabilize craft since antiquity. No doubt there are many yachts sailing today that would have gone down had it not been for the grace of God and some sort of device that slowed the boat down. Towed off the stern with a bridle a speed-limiting Drogue can be used as an emergency steering device to yaw the boat if steering fails. Towed off the windward quarter a speed-limiting Drogue can help maintain directional stability while negotiating a dangerous harbor entrance. Towed off the stern of a vessel in tow a Drogue can all but eliminate the "whiplash" effect and contribute to better control by the towing vessel.
The DELTA Drogue uses the "guide surface principle". The design is a triangular "Delta" shape that provides strong uniform flow separation at all leading edges. Shape retention is achieved by the pressure of the water inside (similar to the "Ballute" drogues used in aerospace applications). The relatively small mouth at the leading edge makes it extremely unlikely that one will get turned inside out (a problem associated with large cones and small parachute drogues). Also, the three ears of the DELTA Drogue have the effect of increasing the Drogue's drag as speed increases. The DELTA Drogue is extremely SIMPLE in design and construction. It is made from heavy duty vinyl coated material at an affordable price. The DELTA Drogue's three lines are made of heavy Nylon webbing and end with a stainless steel swivel (included).
Safety at Sea carries a full line of accessories for use with Sea Anchors and Drogues. Stainless steel hardware, trip lines, anchor rode and rode stow/deployment bags. And we can supply your Sea Anchor rigged and ready for use.
Safety at Sea anchor rode is of nylon double braid - strength, ease of handling - with the advantages of stretch - and breaking loads are very high 5/8"(16mm) is 8000kg Braid construction
makes the condition of the rode always visible. Like to know more about Parachute Anchors and Drogues? Read this in depth article from Ocean Navigator by Earl R Hines and purchase DDDB book by Victor Shane
|