Acquiring A Ready Made Series Drogue

[Don C L]

Originally Posted by thinwater

It is not that the drogues themselves are unstable. Some fabric drogues are stable up to 15 knots or more. It is that when there are waves steep enough to need a drogue, above 5 knots, and the rode is pulled bar tight, as it will be at higher speeds, the frequency of the drogue pulling out of the wave face goes up. This is independent of design and is simply a matter of the geometry of waves. Longer scope helps, but only to a point when the waves are steep. it is the angle of the face that matters. Drogues are stable at higher speeds in even swell.

There are numerous stories of folks using a drogue at high speeds, going like a bomb, and as the storm grows, suddenly the drogue fails and they are screwed.

Like everything expereinces vary, but the point is that as the speed increases above 5-7 knots and loads increase, the chance of sudden failure increases. Just something folks should know. The JSD is designed to avoid this, at the cost of low speed.

Interesting, so this begs the question, if the length of the rode won't prevent pulling out of an upwind wave, is the only potential remedy to add more weight? Say a big lump of lead on a snatch block allowed to ride down the rode? And by the way I think we are speaking of wave steepness (and/or breaking...probably is though) not necessarily wind speed or wave height, no? IME wave steepness can change fairly quick when interference of currents and/or the addition of other waves from another direction, as can happen off headlands, even when the storm or winds don't grow.

[Snowpetrel]

Last time I deployed a drogue I used about 10 meters of 10mm chain (somewhere around 20kg of weight) and about 150+ meters of 18mm polyolefin rope. No issues with it skipping at all. It seemed to go down and stay down very deep, but our average speed was under 4 knots.

I guess with higher average speeds the drag of the rope and drogue will overcome most of the weights effects. Prehaps this shows that the sea claw paravane concept may be a useful part of a multi element drogue.

[kmacdonald]

Originally Posted by Snowpetrel

Last time I deployed a drogue I used about 10 meters of 10mm chain (somewhere around 20kg of weight) and about 150+ meters of 18mm polyolefin rope. No issues with it skipping at all. It seemed to go down and stay down very deep, but our average speed was under 4 knots.

I guess with higher average speeds the drag of the rope and drogue will overcome most of the weights effects. Prehaps this shows that the sea claw paravane concept may be a useful part of a multi element drogue.

Yes, I think the problem with drogues pulling out is an issue with drogue sizing. They must be correctly sized for the boat displacement and the recommended leader length should be used. The devil is in the details.