Winch size for a 752 sq ft junk main sail?

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  • 27 Apr 2015 20:19
    Reply # 3319134 on 3311637
    Deleted user

    Justin,

    You might be interested in this table (technical forum illustrations) I worked up for estimating halyard (f bottom) and sheet loadings for my conversion to a 550 sq ft junk rig. I got the "human range" of 35-45 pounds I think from the Harken blocks site. My sail weighs about 215 pounds and with the 5:1 halyard my theoretical pull at full sail should be 43 pounds. In practice that's accurate. I'm definitely at my strength limit to get the last inches up. I recycled the bermuda rig Barient 21 halyard winch for use with the junk and use it occasionally. Scaling up to 752 sqft from 550 sqft I guess your sail weight at around 325 pounds (?) (Odyssey III material & AL battens and yard). With 5:1 halyard you're pulling 65 pounds, but only at the last 1 or 2 panels. Seems like recycling the westsail halyard or sheet winch would work.

    BTW it is the sheet loadings that get large again depending on the mechanical advantage of your system. The  most wind I've been in is F6 with 3-4 panels up and the estimate of 45-50 pounds of pull on the sheet is accurate.  

    Last modified: 27 Apr 2015 20:34 | Deleted user
  • 25 Apr 2015 11:22
    Reply # 3316376 on 3311637
    Anonymous member (Administrator)

    Justin,

    remember, whatever the manual winch you use or the purchase of the halyard, the energy needed to get the sail up will be the same.

    I suggest you consider some sort of electric winch with manual backup. Personally I found this electric winch handle to be very useful. One thing I learnt from using it was that the consumption of amp-hours was very low. That is no wonder if we reckon on it:

    The net energy needed to lift 50kg 10m up is only around 5000Newton-meter= 5000 Watt-seconds

    If a 12Volt electric winch is to do that job, even with loss to friction etc, the current drain from the battery should be well less than 0.5Ah (with no losses the drain should theoretically be 0.11Ah). In other words, there is no need to be afraid of draining the battery, even if you hoist the sail 5 times a day.

    In comparison, a 12W lamp, left on for 24 hours, will drain 24Ah from a (12V) battery, and even a little 5W lamp will drain 10Ah.

    Arne

  • 25 Apr 2015 09:08
    Reply # 3316352 on 3311637
    Deleted user

    I checked today and my winch is a Barlow 44 so you would definitely need something in the 40's to 50's size range. I suspect that with such a large sail a halyard winch will quickly get moved to the 'must have'. David (the Kiwi one).

  • 24 Apr 2015 06:15
    Reply # 3314907 on 3313495
    Justin Probst wrote:

    Still waiting for Practical Junk Rig to arrive...need to understand the lingo better.

    Justin

    Hi Justin.  If you go here, you will find the Junk Rig Glossary.  Still a work in progress, but I think you may find it helpful, with all the new words and terminology.
  • 23 Apr 2015 04:33
    Reply # 3313495 on 3311637
    Deleted user

    Wow, there are a lot of Davids on this thread. 

    Thanks for the additional information, guys. My wife is very strong for her size. She's got man strength. I call her the Superbeast because she has done 24 chin-ups in one set before. I'm not real worried about her not being able to get the main sail up by herself if she was standing at the mast and we are young but still, there are other things to consider. Fatigue, morale, etc. All of you have convinced me for now to put this winch on my wish list instead of my must have list. After going out the first time, it may get moved to the must have list,

    Still waiting for Practical Junk Rig to arrive...need to understand the lingo better.

    Justin

  • 22 Apr 2015 23:27
    Reply # 3313315 on 3311637

    For my sail of around 600 sq ft, I use two ARCO 2-speed self-tailers, with power ratios of 14:1 high speed and 30:1 low speed. I used to have a 3:1 halyard, but have gone to 2:1, as I find this to be more efficient when used with a big enough winch. I use the high speed, mostly, but sometimes need the low speed when the sail is pressed against the mast or when sailing downwind in a blow.

  • 22 Apr 2015 22:11
    Reply # 3313173 on 3311637

    Hi Justin,

    on Arcadian the main is 700 square feet and the foresail 500 and we need a winch to get either up from the cockpit. By hauling down on the halyard at the mast I can manage either, but not my wife. I have installed two small electric anchor winches on the cockpit coamings, that I got second hand for $250.00 NZ each. These manage OK especially if used in conjunction with someone at the mast hauling down on the halyard. They can do the job on their own but struggle a bit at times, especially if the engine is not running to keep the battery voltage up. This arrangement has worked well and has the added advantage that you can also use them to handle a stern anchor. If I was a bit younger I would probably not have installed them but as I am approaching 70 it is becoming necessary to have the added help in hauling up the sails.

    If you use at least 15% balance on your sail this should ease the sheet pressure sufficiently that you should not need a winch for the main sheet. This should also reduce the weather helm when reaching and running. On Arcadian it also reduced the stress on the yard hauling parrel as the yard attachment point is moved closer to the mast.

    I would recommend that you install an electric anchor winch in a convenient location to serve the halyard and also a stern anchor, size it as an anchor windlass rather than a halyard winch and you should not have a problem.

     Good luck with the conversion.

    David.

    Last modified: 22 Apr 2015 22:20 | Anonymous member
  • 22 Apr 2015 19:12
    Reply # 3312901 on 3311637
    Deleted user

    Great, guys. That answered my questions. Good looking boats by the way.

    Justin

  • 22 Apr 2015 13:18
    Reply # 3312216 on 3311637
    Deleted user

    On our Freedom 39 Pilothouse Schooner we have about 80 square metres of junk sail in total. The original Freedom rig came with 76 sq. m. and a Lewmar 43ST halyard winch. This sits in the cockpit atop the coachroof where it can handle both sails and the sheets and all other lines if we ever need to. We're lucky in that it's electric - recommend that. I can easily get the alloy-battened sails etc up about 1/2 way by hand; all the way if I have to. Usually I get them 1/3 up then use the power.

    Last modified: 22 Apr 2015 13:20 | Deleted user
  • 22 Apr 2015 04:17
    Reply # 3311768 on 3311637
    Deleted user

    You are quick off the mark! My winch is quite old so I don't know how the sizing compares with modern winches but in looking for a replacement winch I have been looking at winches in the 40's size ranges so as to get more power. There is a photo of my winch set up in photo 7 of my 'New Sail' member profile photo album. Since that photo I have added some extra jammers to manage lines. I use the winch for hoisting the sail and for the luff hauling parrel which has a high load on my particular sail.

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