srm
Well-Known Member
The upper limit of my open water experience is a force 9 with what was getting on for a fully developed sea state well east of Fair Isle. Since then I have tried to avoid repeating the experience, and have considered how each boat I owned would best handle it.
My last boat came with two parachute anchors, the present boat with one that is probably too small to hold her up in to the wind. Neither had the rest of the gear to deploy the para anchors so they were effectively useless.
However, looking back on that force 9 the last thing I would want to do is try to point up into it as the forces of a breaking crest are incredible. (Afterwards we found the contents of every locker jammed against its aft bulkhead due to the repeated accelerations down the faces of waves while towing warps).
Having read every report I can find from people who have used parachute anchors off the bow I came to the conclusion they are fine for a limited range of sea states, but that once the waves start breaking (as opposed to tops tumbling and blowing off) the loads on the bridle and warp tend to cause them to fail. Theory says keep the warp one or two wave length long so boat and drogue are in the same part of their respective waves. Unforunately, the sea is not that considerate and wave lengths in any sea that justifies a sea anchor will be variable resulting in shock loads on the warp.
Likewise, speed limiting drogues may not be in the right place or big enough to hold the stern into a breaking wave as it strikes. One manufacturer actually has a warning on their web site that the drogue may not hold the boats stern up in a breaking wave strike.
My prefered option is to run with the waves and ride the punches. Last winter I made up a Jordan Series Drogue and fitted strong points on the quarters outside the hull for attaching it. Quite simply it seems to offer the best protection and is very easy to deploy. I like the fact that it will let the boat make about 1.5 knots down wind most of the time as that will put less strain on boat and crew, but should it experience a breaking wave strike will automatically apply an increasing force to hold the stern into the wave as the line straightens and more cells become active. Also, with so many small drogue cells a few getting damaged does not significantly effect the overall performance. However, the literature on the Jordan Drogue does warn of an initial acceleration of up to 3G in a breaking wave strike.
I also carry two speed limiting drogues (ex liferaft) for less extreme conditions, and have used them to hold back while waiting for the tide to turn rather than arive early in a tide race with wind still aginst tide.
I would suggest that anyone who carries a drogue or sea anchor would be well advised to try deploying and recovering the gear in a modest force 6 to 7 before its needed for real.
My last boat came with two parachute anchors, the present boat with one that is probably too small to hold her up in to the wind. Neither had the rest of the gear to deploy the para anchors so they were effectively useless.
However, looking back on that force 9 the last thing I would want to do is try to point up into it as the forces of a breaking crest are incredible. (Afterwards we found the contents of every locker jammed against its aft bulkhead due to the repeated accelerations down the faces of waves while towing warps).
Having read every report I can find from people who have used parachute anchors off the bow I came to the conclusion they are fine for a limited range of sea states, but that once the waves start breaking (as opposed to tops tumbling and blowing off) the loads on the bridle and warp tend to cause them to fail. Theory says keep the warp one or two wave length long so boat and drogue are in the same part of their respective waves. Unforunately, the sea is not that considerate and wave lengths in any sea that justifies a sea anchor will be variable resulting in shock loads on the warp.
Likewise, speed limiting drogues may not be in the right place or big enough to hold the stern into a breaking wave as it strikes. One manufacturer actually has a warning on their web site that the drogue may not hold the boats stern up in a breaking wave strike.
My prefered option is to run with the waves and ride the punches. Last winter I made up a Jordan Series Drogue and fitted strong points on the quarters outside the hull for attaching it. Quite simply it seems to offer the best protection and is very easy to deploy. I like the fact that it will let the boat make about 1.5 knots down wind most of the time as that will put less strain on boat and crew, but should it experience a breaking wave strike will automatically apply an increasing force to hold the stern into the wave as the line straightens and more cells become active. Also, with so many small drogue cells a few getting damaged does not significantly effect the overall performance. However, the literature on the Jordan Drogue does warn of an initial acceleration of up to 3G in a breaking wave strike.
I also carry two speed limiting drogues (ex liferaft) for less extreme conditions, and have used them to hold back while waiting for the tide to turn rather than arive early in a tide race with wind still aginst tide.
I would suggest that anyone who carries a drogue or sea anchor would be well advised to try deploying and recovering the gear in a modest force 6 to 7 before its needed for real.