O'day Daysailer ll Mod and Conversion

  • 05 Jan 2023 01:01
    Reply # 13045073 on 13021193
    Anonymous member (Administrator)

    Bill asks: Any opinions on projected performance between the two sails? (I had to ask)

    Modesty (and prudence) will probably preclude a reply from either of the designers, so I will venture the following: without carefully conducted matched trials I doubt if the question could be answered - and even then I doubt if there would be a clear cut difference. The one with lower aspect ratio and longer boom might be (very slightly) more of a handful down-wind than the other - but in either case one would expect the helm to be a bit "hard mouthed" if over-canvassed when broad-reaching and running down wind - this is inevitable with a low balance cat rigged dinghy in a bit too much wind. (In that situation you'll soon learn to reduce sail a little when necessary, and raise the centreboard a little or tilt it aft if you can - - then sit right at the back and hang on tight!)

    Four different panels need to be individually lofted for the 7-panel Johanna sail (DIY well -documented by Arne) -  and five different panels lofted for Paul's 5-panel sail (not quite so simple to loft, though I dare say for a fee Paul will provide computer-generated patterns).

    I would make the comparison on two other matters, rather than "performance":

    (1) aesthetics. That's in the eye of the beholder.

    (2) running rigging requirements. I would be interested to know what each of the designers proposes in the way of sheeting system, and the suite of sail-adjusting parrels. I suspect these things can only be finally decided after a little experimentation and tuning, but I suppose each of the designers would be able to make some initial suggestions and it might be interesting to compare them.

    Last modified: 05 Jan 2023 01:13 | Anonymous member (Administrator)
  • 05 Jan 2023 00:27
    Reply # 13045021 on 13043995
    Anonymous wrote:

    Bill.
    That fan-sail looked good. However, I started wondering how the CE could get right with that long boom and little mast balance. I therefore imported Paul’s sailplan into my QCAD drawing board and scaled it up until that 6.00m mast height got right. I double-checked by controlling the batten length and sail area, and it was all fine.

    The hull, on the other hand, became too big. According to Sailboat Data, the LOA should be 5.11m (16.75ft). The LOA of the hull on Paul’s sailplan comes out at about 6.10m  -  well over 3ft longer.

    One of us must have missed something...

    Arne


    Yeah, in my haste I used the wrong scale factor.... the proportions are right though. However it's just a rough drawing to see if Bill liked what he saw...

    Turning the proposal into working drawings would have brought the issue to light....

    However at 10 Sq.M the sail area of the correctly scaled drawing is inline with what Bill would like.

  • 04 Jan 2023 12:53
    Reply # 13044080 on 13021193

    Hmmm, thanks for checking this. Well, if the hull is 3 feet longer than it probably won't fit that sail... I'll run it by Paul.

    The drawing I gave both of you is the same and based on my measurements. Actually, in my drawing, the LOA is 16.583, measured from my boat. I've checked all these measurements a bizillion times :) 

    Any opinions on projected performance between the two sails? (I had to ask)

    *I just checked the measurements against my drawing, and yes, indeed Paul's are off, and your measurements are the same as mine. 

    Last modified: 04 Jan 2023 13:05 | Anonymous member
  • 04 Jan 2023 10:06
    Reply # 13043995 on 13021193
    Anonymous member (Administrator)

    Bill.
    That fan-sail looked good. However, I started wondering how the CE could get right with that long boom and little mast balance. I therefore imported Paul’s sailplan into my QCAD drawing board and scaled it up until that 6.00m mast height got right. I double-checked by controlling the batten length and sail area, and it was all fine.

    The hull, on the other hand, became too big. According to Sailboat Data, the LOA should be 5.11m (16.75ft). The LOA of the hull on Paul’s sailplan comes out at about 6.10m  -  well over 3ft longer.

    One of us must have missed something...

    Arne


    Last modified: 04 Jan 2023 10:08 | Anonymous member (Administrator)
  • 04 Jan 2023 00:33
    Reply # 13043645 on 13021193

    Here's Paul's sail design for my boat. I put it next to Arne's so we can see them side by side. Thoughts? 


    2 files
    Last modified: 04 Jan 2023 00:35 | Anonymous member
  • 04 Jan 2023 00:30
    Reply # 13043643 on 13021193

    Arne, thanks mate, sounds good . . . make the sail first, and now! great idea!

    I've been reading through your notes, and yes, I need a few passes for my little artist brain to process the math hahaha! Seems clear and concise so far though, thanks for making all this available, and sorry all your pics went MIA. Bummer! 

    Your design and process is nicely documented and seems very approachable to the new-to-a-sewing-machine-dude . . . luckily, I have stood behind a bandsaw a whole bunch :) 

    I'm also looking at a design from Paul Thompson and I'll post a pic of that too. It'll be sorted soon and we'll be on our way, thanks!

  • 31 Dec 2022 19:57
    Reply # 13040085 on 13021193
    Anonymous member (Administrator)

    Bill,

    my experience is that time is running terribly fast when one is to start a rigging project.
    Since there is no weather for out-door work these days (too cold anyway for gluing), I suggest you start with the sail, which is typical indoor work.
    When you have decided on sail to use, you need to collect some canvas to make it from (around 3oz.), webbing and paper for lofting the sail. In case you choose to make the last sail I suggested, the one with B = 3.15m, then you need to draw it up in detail. This sail is based on a standard Johanna70 master sail with AR = 1.85..

    • ·         I suggest you download and print out Chapter 4 and 5 of TCPJR , found here, where the master sails sit..
    • ·         You need two printouts of Sheet 1 and Sheet 2 of that AR= 1.85 master sail.
    • ·         All the dimensions on sheet 2 must be scaled down, using scale factor Fl = 0.620429.  I write the result in mm-resolution, but I am plenty happy if I manage to cut and sew with centimetre accuracy (1cm = 10mm)
    • ·         The other Sheet 2 can be used to produce “Sheet 3”, with the Round added for generating camber in the sail. The numbers needed can be found if Fig 4.5.
    • ·         One of the printed out Sheet 1 can be used for planning the batten pocket, turning it into Sheet 4.
    • ·         Sourcing sailcloth and webbing takes time, start now.
    • ·         Floor space for lofting the sail needs only be big enough to let you loft one panel at a time. The sail for my Ingeborg was lofted and sewn together in my cramped living room. Unfortunately, a 43-photo album, showing the sewing process in detail, has been lost by Apricot (along with 200 more photos). I could rebuild that album, but it is quite some work, and I am afraid they will just get lost again.
    • ·         If you haven’t used a sewing machine before, that sounds like a daunting obstacle. However, sewing a junk sail, using Amateur method B, is much easier than sewing clothes, or real, western sails. If you can saw along a line with a bandsaw, then you will soon be able to sew alone a line as well.

    I suggest you read those two chapters (4 and 5) carefully and take notes before you start.

    Good luck! 

    Arne


    Last modified: 31 Dec 2022 20:07 | Anonymous member (Administrator)
  • 31 Dec 2022 02:19
    Reply # 13039540 on 13021193

    Ahh Graeme, yes my friend, very good, thanks. 

    I'm in compete agreement with you here, sounds good. 

    And, I'm by no means dismissing Arne's advice, as much as it may have sounded like it. My plan is certainly to get her in the water this summer. I can probably get the basic coversion done and start sailing, and then chip away at the mods, and have those together before next winter. But these are not deadlines damnit :) 

    More to come :) 

  • 31 Dec 2022 01:02
    Reply # 13039522 on 13021193
    Anonymous member (Administrator)

    The boat is currently a day sailer.

    If you were to put Arne’s rig in it and do some day-sailing next summer you would probably be making a good start.

    If that doesn’t appeal, you could go ahead straight away and increase the size of the cuddy somewhat, as you have planned, give it the rig Arne suggests, make a secure compartment below the floorboards for carrying heavy stores, a place to stow a tent or canopy, somewhere for sleeping bag, cooking utensils etc etc - and then I think you would have a pretty good camper-cruiser.  Careful placement of reserve buoyancy will add to your confidence. It will enable extended cruising if you watch the weather. Once out on the water you will be able to push the boundaries a bit and judge for yourself what the limitations are. You won’t be lacking opportunities to experience stressful situations. That’s as far as you can take that hull, in my opinion – but it’s a very long way from merely a junk rig conversion, and a very long way from merely day sailing.

    The rig will be good, but in my opinion, ultimately you will find that the hull is not ideal for “potentially nasty environments for long periods of time…” 

    But it will be a good enough platform for preparing yourself and planning for that.

    In other words (your own): 

    "...I see this boat as a training ground for the next boat... ...So, it's worth it to put in a little extra effort to make the boat something a bit more capable than the fair-weather daysailer - the comfort in knowing that I can push her (and myself) in ways that foster slightly more significant mistakes and learnings than one would assume from a typical open dinghy..." 

    Best of luck with your project.


    Last modified: 31 Dec 2022 01:19 | Anonymous member (Administrator)
  • 30 Dec 2022 17:27
    Reply # 13039232 on 13021193

    Or in straight-shooter vernacular. 

    I see this boat as a training ground for the next boat. Even "just" a conversion to JR is a good amount of time and $. I'll probably be sailing this vessel for a number of years before assembling "God."

    So, it's worth it to put in a little extra effort to make the boat something a bit more capable than the fair-weather daysailer - the comfort in knowing that I can push her (and myself) in ways that foster slightly more significant mistakes and learnings than one would assume from a typical open dinghy. There needs to be room to grow. 

    Maybe this explains my constant probing for ideas and options within this thread before taking action. Not to mention, its winter here, the boat is covered, on the hard, and I have some time. 

    Ok. Now I'm showing my idealistic intensities . . . many people can't handle this part of me hahaha!


    Last modified: 30 Dec 2022 17:28 | Anonymous member
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software