Alden 42 Conversion

  • 10 Aug 2020 21:48
    Reply # 9156410 on 9154403

    Hi Shannon,

    time to draw in the sail plan and work out where the COE will actually be. It looks to me as if the sail plan will need to move forward a bit to get the balance that will be needed. It looks as if the CLR has moved forward a bit when redrawn without the rudder. I can not really tell until the rig is drawn. You may find it necessary to move the foremast forward to just aft of the fore cabin bulkhead to get it to balance. The main mast may also need to move forward a bit from the position you show.

    All the best, David.

  • 10 Aug 2020 18:56
    Reply # 9156033 on 9155928
    Deleted user
    Anonymous wrote:

    Shannon, 

    I worked through this a while back, we ended up settling on a schooner rig with 12% lead, unfortunately we're still not in the water to test it out.  You can see some of the details in this JRA thread which might have some other related discussion that might be useful.  For us, the schooner rig was easy to commit to as our mainmast was already in the right position and we only had to move the foremast.  

    Daren, I'll follow that thread.  Thank you for your advice, I've updated the drawing to reflect yours and David's suggestions.
  • 10 Aug 2020 18:55
    Reply # 9156022 on 9154403
    Deleted user

    I've incorporated the feedback and came up with the attached mast positions.  Assuming 45m2 on the mainsail and 35m2 on the foresail.  The mainmast is positioned a bit further back than suggested by David, due to planned modifications to the interior layout.  

    Thoughts?

    Shannon

    1 file
  • 10 Aug 2020 18:14
    Reply # 9155928 on 9154403

    Shannon, 

    I worked through this a while back, we ended up settling on a schooner rig with 12% lead, unfortunately we're still not in the water to test it out.  You can see some of the details in this JRA thread which might have some other related discussion that might be useful.  For us, the schooner rig was easy to commit to as our mainmast was already in the right position and we only had to move the foremast.  

  • 10 Aug 2020 08:30
    Reply # 9155175 on 9154403

    Hi Shannon,

    when calculating COA do not include the rudder area. If you do then you guarantee some, if not excessive, weather helm. On Arcadian I started with 8% lead but this lead to heavy weather helm. I added a keel extension aft and this brought the lead up to 11% and she still had more than adequate weather helm. So with a schooner rig I advise a lead of 10 to 12%. Having some weather helm is good as you can then trim the foresail for best performance and then trim in the main until she balances, this will likely lead to her sailing herself on most courses from hard on the wind to a quartering reach.

    I would suggest a slightly smaller foresail, 35 square metres and a main of 45 square metres. You will have more space for a good lead for the main sheet and using a smaller foresail means the sheeting distance will be a bit less. Also the smaller foresail will put less weight into the bow of the boat.

    All the best with the project.

    David.

  • 10 Aug 2020 06:36
    Reply # 9155053 on 9154974
    Deleted user
    Anonymous wrote:

    Hi Shannon,

    Interesting project!!

    If it was my boat I would be looking at a schooner rig with the foremast right at the forward end of the coach roof and stepped in the V between the forward berths. The main mast would be at the aft end of the table in the saloon, just aft of the indicated CLR. This would provide better sheeting angles for the sails and would make the sails closer in area to each other, hence easier to handle and balance. This would also give better redundancy in case of a sail malfunction as there would be enough area in either sail to get you home. What is the existing sail area on the boat? I find that 50 square metres is about the maximum I want to go to as I have had problems with batten breakage when over that area. Also sails over 50 square metres get to be too heavy for geriatrics like me and need electric winches in order to raise them.

    The CLR looks close to where I would imagine it but it is easy to make a cutout in thin card of the underwater area (without the rudder) and by balancing it on a straight edge this  will give the CLR position.

    Best of luck with the project.

    David.

    David,

    Thank you for the advice.  

    Concerning the CLR, I calculated it using the cutout method and included the rudder.  Upon consideration however I should compare the results with and without the rudder.  Maybe even take the average.

    Concerning the schooner rig.  I am a very inexperienced sailor.  Even so, your observations reinforced my nagging doubts about the wisdom of using the existing mainpost position and step.  

    I especially value your feedback concerning sail handling.  The existing sail area is 70 m².  The dream is to sail her in retirement, which isn't far away.  Svelte sails appeals to both my sense of aesthetics and the realities of life (I'm recovering from spinal surgery).  Given your feedback ~40 m² on each mast would seem to accommodate trimming while being manageable.

    Your advice is exactly what I am looking for.

    Shannon
  • 10 Aug 2020 05:18
    Reply # 9154974 on 9154403

    Hi Shannon,

    Interesting project!!

    If it was my boat I would be looking at a schooner rig with the foremast right at the forward end of the coach roof and stepped in the V between the forward berths. The main mast would be at the aft end of the table in the saloon, just aft of the indicated CLR. This would provide better sheeting angles for the sails and would make the sails closer in area to each other, hence easier to handle and balance. This would also give better redundancy in case of a sail malfunction as there would be enough area in either sail to get you home. What is the existing sail area on the boat? I find that 50 square metres is about the maximum I want to go to as I have had problems with batten breakage when over that area. Also sails over 50 square metres get to be too heavy for geriatrics like me and need electric winches in order to raise them.

    The CLR looks close to where I would imagine it but it is easy to make a cutout in thin card of the underwater area (without the rudder) and by balancing it on a straight edge this  will give the CLR position.

    Best of luck with the project.

    David.

    Last modified: 10 Aug 2020 05:21 | Anonymous member
  • 09 Aug 2020 22:32
    Message # 9154403
    Deleted user

    Hello,

    I hope this finds everyone well and happy.  My project boat is an Alden 42 which was available both as a sloop and a ketch.  Mine is rigged as a sloop, #929C 'September Song".  

    I've read PJR and am studying the feasibility of a junk rig.  :)  I am seeking feedback on my calculations and planning to date.   I find myself in the uncomfortable position of having a CLR much further aft than looks correct to my untrained eye.

    I've based my calculations on a vector drawing that I converted by tracing the outlines from the bitmap available at sailboatdata.com.  Attached is a screen capture of the vector drawing positioned over the bitmap.

    At this stage I am trying to answer the following questions:

    1. Can I use the existing mainmast step and position?
      1. If yes, where will I need to place a second mast?
      2. If no, where do I need to place the mainmast?

    From my drawings and calculations, it appears that I can use the existing mainmast step and position.  Extraordinary it also appears that I can position the mizzen mast in the location show in her sister ships rigged as ketchs.  

    Since this is an ideal outcome, I don't trust it.  All feedback, concerns and armchair speculation are welcome, nay encouraged.


    Regards,

    Shannon

    1 file
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