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Thread: Drogue or Sea Anchor? What and When?

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  1. #1
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    Default Drogue or Sea Anchor? What and When?

    We have a PAratech Sea Anchor, never used it, but have seen some videos of cats using them off the bow. Have also read stories of those that ran from storms, if the speed became too much they ran a drogue (either a true one or makeshift) off the stern. I am curious what the consensus is on what and when, I imagine if the waves are just too big to ride down or surf down, a parachute would be safer? BTW I hope to never need either, but the knowledge could be a lifesaver.

  2. #2
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    Default Re: Drogue or Sea Anchor? What and When?

    Parachute anchor demands very strong attachment points on the bows, and needs to be rigged ready to deploy before the storm. It needs to be big enough that the wind and wave driven speed astern is absolutely minimal, or rudder damage will occur.

    The series drogue provides an alternative approach to the parachute and will also minimise movement through the water, but demands that the aattachments are on the stern. Dinghies on davits are an obvious weakness to this approach.

    single drogues are great for slowing a boat down, but not much benefit in survival conditions.
    Insanity is continuing to do the same thing and expecting different results

  3. #3

    Default Re: Drogue or Sea Anchor? What and When?

    A para-anchor is for stopping (eg to allow a storm to pass over quickly), drogues are for slowing down when conditions are bad but not necessarily survival conditions. Survival conditions for some boats are just nasty or even fun for others so it depends on you boat.

  4. #4
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    Default Re: Drogue or Sea Anchor? What and When?

    Quote Originally Posted by Peter View Post
    ..........., drogues are for slowing down when conditions are bad but not necessarily survival conditions. ...........
    If you are talking just drogues then I agree with you. If you include the series drogue in this, you are totally wrong. Even USCG consider the series drogue to be the best bit of kit in extreme conditions. See the jordan site, and look at some of the tank tests. Read some of the Drag Device Database entries.
    Insanity is continuing to do the same thing and expecting different results

  5. #5
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    Default Re: Drogue or Sea Anchor? What and When?

    As for loads on the attatchment points I have read several articles stating that with a sufficiently long enough line, with adequate stretch, the load on the atatchment points is barely greater than the loads on the same points anchoring in a blow. Our plans are Bahamas Exhmas, eventually Caribbean. At what point would you feel you were surfing too fast and needing to slow down if running with it?

  6. #6

    Default Re: Drogue or Sea Anchor? What and When?

    Quote Originally Posted by Talbot View Post
    If you are talking just drogues then I agree with you. If you include the series drogue in this, you are totally wrong. Even USCG consider the series drogue to be the best bit of kit in extreme conditions. See the jordan site, and look at some of the tank tests. Read some of the Drag Device Database entries.
    I don't think a JSD is the panacea for all extreme conditions. Not wishing to be cynical in anyway but the Jordan site, however upstanding, has a vested interested. The Database also makes specific distinctions between monos, types of monos and catamarans.

    If my understanding is correct Jordan expect waves to break over the stern and into the cockpit and they recommend that the crew go below and strap themselves in when deployed. This may be the best compromise for a mono, that by default presents a small area aft and has a long keel that is likely to yaw to a sea anchor. But I would not like to stop a catamaran (or some modern wide stern monos) stern to wind and breaking waves as JSD suggests. A cruising catamaran, in particular, presents a huge stern area and the impact forces would be worrying to say the least. That is not to say the JSD doesn't have it's place.

    You could simulate the effects next time there is a moderate blow, with breaking waves in your local anchorage set up and anchor stern too.

    There must be members of this forum that have used a para-anchor or JSD and in what conditions?

    I have used a drogue on several occassions in strong winds and NON breaking waves to slow down and time arrivals.

    Richard Woods I think used a sea anchor off Mexico. If I recall correctly Team Phillips towed a drogue at some point but they presented a very streamlined stern and given their "sturdy" bow configuration a sea anchor may not have been a good idea not sure it was survival conditions either.

  7. #7
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    Default Re: Drogue or Sea Anchor? What and When?

    Quote Originally Posted by Peter View Post
    ..............I would not like to stop a catamaran stern to wind and breaking waves as JSD suggests. A cruising catamaran, in particular, presents a huge stern area and the impact forces would be worrying to say the least. .......
    I acknowledge that some catamaran designs are not optimal for a JSD, and I looked at that aspect as much as a lot of others when choosing my boat. However, your comments suggest a lack of understanding of the JSD concept. If you look at the design again, you will notice a significant weight at the end of the rig (in my case 150 cones, and 7metres of 10mm chain). This weight is crucial to the design. As the boat and JSD are overtaken by a wave, and fall off the back, the boat slows almost to a stop, the weight at the end of the rig drops a large proportion of the droguelets out of action by being well below horizontal. This is the situation when the next wave arrives, the first impact of that wave (even a breaking wave) is met by little resistance to boat moving forward because there are very few droguelets stopping it. As the boat increases speed, the rig straightens out and more and more droguelets come into action, slowing the boat and pulling it through the wave.
    That initial impact force is mostly dissipated by the movement of the boat. In a big breaking wave, it is certain that the cockpit will get a good amount of water, so LARGE drains are necessary. If your boat is designed such that the wave would be funnelled into the cockpit, it is probably not a good idea to use a JSD. Personnally this is not a design worry in my boat!

    I have no argument against the use of drogues to slow the boat in lesser storms, and the example of the Abbott Drogue in "Exit Only's" storm management is a prime example of this. However, these will not be sufficient in survival storm settings, and this is where the JSD is suitable for blue water designed catamarans.
    Insanity is continuing to do the same thing and expecting different results

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