Design and Use of Drogues

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  • 13 Jun 2018 08:52
    Reply # 6307994 on 833331
    Anonymous member (Administrator)

    Rene,

    in that case, if you have a stout bucket on board, you could even use that one as a drogue. I suggest you try a bucket, just to see if it produces enough resistance.

    Arne

    Last modified: 14 Jun 2018 09:16 | Anonymous member (Administrator)
  • 13 Jun 2018 06:43
    Reply # 6307874 on 833331

    Thank you very much Arne, you are very helpfull

    I read the article and its clear enough how to do it now.

    i will go for the smallest size, probably even a bit smaller with a diameter of 30cm, 

    my boat is 6m and 400kg.


    Regards, Rene

  • 12 Jun 2018 17:44
    Reply # 6305819 on 833331
    Anonymous member (Administrator)

    Rene,

    Now I have summed up the little I know about making a parachute drogue.

    It is called «20180611 making a parachute drogue”. It is just a draft (ver. 20180612a), but hopefully it will soon be replaced with a proof-read version. Nevertheless, the diagram and photos should tell most of what you need to make one yourself.

    Good luck!

    Arne

    PS: When the link dies, the file can still be found in ‘my’ JRA folder, under “How-To notes”.

    PPS, 20180614: The final version has now been up-loaded (ver. 20180614a).

    Last modified: 14 Jun 2018 09:09 | Anonymous member (Administrator)
  • 11 Jun 2018 10:00
    Reply # 6302956 on 833331
    Anonymous member (Administrator)

    Rene,

    The last month we have had extraordinarily fine weather in southern Norway, so I have been sailing quite a bit.

    I have only tried the smallest, 0.125sqm parachute drogue, but I have found it to be so efficient that it has been used every time I hoist the sail (14 outings, so far). As we motor out of the inner harbour, I just shut down the engine and toss the drogue overboard, with its  4-metre line clipped over the lee mooring bit. Within a couple of boatlengths the speed has dropped to below 1.0 kts. With the tiller locked a bit to leeward, the boat tries to head up, but is unable to tack, so I get plenty of time and room for hoisting the sail, and squaring up the lines.

    Since this smallest drogue turned out to be powerful enough, I find it very easy to retrieve and coil up the line (around the drogue itself) and stow it away.

    I recon this to be a grand success for my needs.

    Some day, I guess I must produce an illustrated write-up about how to make it…

    Arne


    Last modified: 12 Jun 2018 07:41 | Anonymous member (Administrator)
  • 10 Jun 2018 23:07
    Reply # 6302545 on 833331
    Hello Arne, some time back you mentionted a set of parachute drogues and a ball fender you want to use when raising or lowering sail.

    I like the idea, 
    I typically start sailing in narrow waters and it won’t be the first time i ended up too close to the shore.

    Hope you have an update
    Regards, Rene
  • 02 Apr 2018 09:47
    Reply # 6010689 on 6009600
    Graham Cox wrote: Perhaps better to use tested gal shackles for the JSD and replace them when they get rusty. 

    Yes, I'd be using green pin industrial lifting shackles, with a large, powerful drogue.
  • 02 Apr 2018 09:23
    Reply # 6010684 on 833331

    [Webmaster: could we perhaps retitle this topic something like:"Discussion of Design and Use of Drogues", as we've drifted a long way away from the Seabrake?]

    As always happens, thinking about something like this gets me wondering about whether there are any design improvements to be made to drogues.The main requirement, it seems to me, is to get an even drag, whatever the wave action. The JSD works, as a stopping drogue, but is laborious to make, and to recover once deployed (and is more powerful in its action than most people require, in less than extreme conditions). The JSD achieves this by putting a large number of cones into all parts of the circulation of water particles within the wave, and many people have wondered whether fewer, larger cones, spaced out in the same way, would be easier to make, deploy and recover. The Seaclaw achieves this by diving, and putting one drag-producing item deeper below the  waves. The Galerider works by creating turbulence as the water passes through a mesh, rather than producing hydrodynamic forces by acting upon a cone.

    Could there be, I wonder, a single device (or a small number of devices daisy-chained together), made of mesh, designed so as to dive and thus needing less passive weight to get deeper into the water? I think so.

    Last modified: 02 Apr 2018 09:47 | Anonymous member
  • 02 Apr 2018 00:00
    Reply # 6010286 on 833331

    I have also lashed my halyard block to the yard, avoiding the use of a metal bracket, but even the bleeding blocks have stainless lugs.  I seem to recall seeing some blocks, used on racing yachts, that have dyneema strops rather than stainless hardware, which might be an answer.  They were, of course, hideously expensive.

  • 01 Apr 2018 19:29
    Reply # 6010110 on 833331

    SNAP....I have stainless shackles on my halyard blocks too! With globslisation and the dubious grades of steel you have these days, it is hard to know what you are really getting. I threaded several loops of dynema on the anchor point between yard and halyard.  Once I get up the mast I will do the same at the mast cap. I think if I had a drogue, I'd back it up with dynema.

  • 01 Apr 2018 00:16
    Reply # 6009600 on 6009041
    Roger Scott wrote:

    The attached photo shows Pete in action repairing the drogue anchor point. He said the caption should read "even the skipper gets sea sick!"


    Great photo and vid, Roger, and a great insight into JSD deployment.  Pete has used that drogue many times, so I guess the shackle had been loaded up a lot prior to failure.  As you say, it does not increase one's faith in stainless.  Good for handrails!  Perhaps better to use tested gal shackles for the JSD and replace them when they get rusty.  I have stainless shackles for my halyard blocks and masthead cap, and am uncomfortable with them, but tell myself that the halyard is not under much load on a junk.  And I have a backup halyard.
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