Opinions on this newbie amateur daysailer

Discussion in 'Boat Design' started by Murdock, Oct 20, 2006.

  1. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    Again, thanks a lot for your concern and appreciate so much the effort you are making on helping me.

    "The outer skin has an area of 5.77 m2." sorry, the outer skin is about 7.20m2...
    well, as you stated, maybe I have mixed some numbers,or the plywood here comes from some heavier wood. checked again measures & area sum, got again about 15m2 total developed surfaces (including reinforcements)
    on a 3mm ply basis @ 700kg/m3 wood density I got about 32 kg
    adding 2x300 biaxial cloth on outer skin and 1x300 on inner skin, on a 50%/50% resin/cloth basis, i got another 28kg (probably more near to 35kg)
    total summon rounds 67/70kg (hull + oars + rudder)
    on a 6mm ply basis, total hull weight rounds 100kg... will check on weekend the posibility of reducing reinforcement sizes to gain some weight.
    happy weekend
    Murdock
     

    Attached Files:

    • m2.jpg
      m2.jpg
      File size:
      112.5 KB
      Views:
      769
  2. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    Excuse me, may I ask another question?
    as time went by, dont't know how or why happened, the original model has run a severe surgery program, loosing some centimeters in his (or her) beam... (would prefer this to happen to my wife instead:D ) maybe freeship is the guilty guy, or some other weird thing happened... as results, the original hull was intended to be 1.40m beam, and the freeship resulting model ended about 1.06 (really, what a diet!!!)
    As result of this, I'm getting a bit nervous about it's behaviour on a theoretical 20knot breeze
    (maybe a couple Sumo fighters can do adequate righting...:D :D :D )
    alas, here is a comparative of both initial & final hulls:
     

    Attached Files:

  3. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    well guys, about a week of a pure McDonald's 10.000 daily calories diet, the hull got back to it's weight..:D
    here is the result.

    thanks a lot for all help received.
    Murdock Stevens
     

    Attached Files:

    Last edited: Nov 14, 2006
  4. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    Well, guys, sent today the files & ply to the CNC Router, hope next week begin to post some photos.
    thanks to all the help received.
    Murdock
     
  5. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    CNC fames arrived this afternoon

    Dec 01/06.
    Well guys, CNC frames arrived this afternoon, (42 frames)
    Expecting tomorrow to begin assembling them for the concrete molds.
    here some photos.
    By the way: Sails, photo of new design (with some help from a friend's Sailcut 4 proggie) on pricing/quoting stages
     

    Attached Files:

  6. CT 249
    Joined: Dec 2004
    Posts: 1,701
    Likes: 78, Points: 48, Legacy Rep: 467
    Location: Sydney Australia

    CT 249 Senior Member

    She's very narrow; look at a Merlin Rocket for comparison; similar LOA but about 7'2" maximum beam.
    Bow sections look a little bit too Veed to my eye, for a boat of this DLR and speed. And with the extremely flat bottom and rather tight bilges, she may have to be sailed very upright; not necessarily easy.

    Looks nice, though. I'm no designer, I may be miles off beam with these comments.

    I'm confused about the actual hull weight; for an example, the hull of the Tasar (similar LOA) weighs as little as 59kg and lasts in good racing condition for 30+ years.

    EDIT - Sorry, I posted before I realised how far aloing the project was.
     
  7. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    Hi, CT, very narrow? well, I have never sailed a Merlin, but a 14' x 7'2" seems to me like a raft... (2:1 ratio, Jeesss, applied to a VOR70 it means about 35' beam... surely won't need canting keel at all):D
    Flat bottom? from optis, lasers, moths, even voodoo skifs, all of them have quite a flat bottom and nobody said it's a difficult to sail any of them (well, mothies surely aren't for me on my actual weight)
    Hull weight is by now a theorical estimate.
    QUOTE Myself: about 15m2 total developed surfaces (including reinforcements) on a 3mm ply basis @ 700kg/m3 wood density I got about 32 kg adding 2x300 biaxial cloth on outer skin and 1x300 on inner skin, on a 50%/50% resin/cloth basis, i got another 28kg (probably more near to 35kg) total summon rounds 67/70kg on a couple of weeks I'll tell you more exactly as the first hull comes out from the molds... however, I promise to be extremely careful on the resin thickness to achieve the minimal possible weight..:D
    thanks for your comments.
    M
     
  8. CT 249
    Joined: Dec 2004
    Posts: 1,701
    Likes: 78, Points: 48, Legacy Rep: 467
    Location: Sydney Australia

    CT 249 Senior Member

    Yep, the Merlin's dimensions do look extreme; but they are among the fastest non trapeze/non wing boats around, because of the high RM. And as one of the most highly-developed 14s around, it seemed like an appropriate boat to look at. They were skinny, until the '60s, when they found that flare = fast.

    Looking at comparable boats; the Tasar's beam is 1.75m; the modern NS14 is 1.83m (I think) and a lot quicker than the Tasar, which is basically an old NS14 with a bigger rig and angled bow; Vanguard 15, 5ft 5; National 12's beam is 6ft 6. The WIndmill is narrow. All of the three development classes here have gone for maximum gunwale beam. Of course, you may not want the leverage, because it comes with other problems.

    My comment about the flat bottom may be wrong; looking at the lines plan on this page, it seems that the bilge is softer than it looked when I was lookng at the coloured version earlier. Or maybe I just got it wrong.

    The comment referred to the fact that most boats with very flat bottoms, tight bilges have to be sailed very upright, very accurately, if they are not to lose speed; this is much more critical than in boats with more rounded bilges. This applies to boats like UK Cherubs, Moths, 12 Foot Skiffs, etc. There's nothing wrong with flat floors and tight bilges, it can be a really quick shape, but it is from all accounts a lot more "critical" to sail than a slightly more moderate shape. However, I may have been mislead in my gut feeling about your shape.

    PS - the boat in the picture you attached in one of your earliest posts is a 29erXX - a 29er with an extra trap, bigger rig, and transom extensions.
     
  9. Murdock
    Joined: Aug 2006
    Posts: 24
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brown & smelly Water nowadays...

    Murdock Junior Member

    CT, thanks again for your comments,
    This design intentions were basically a tryout of a "super laser" or something alike, as we're all getting tired of sailing on lasers as the only option here down south (Uruguay/South America).
    As results of being out of the sailing world circuits here down, there is no development, no innovation, no interesting classes, just when kids get out from optimist at 15 years, only options here were lasers, some old snipe, getting into a bigger one's crew or quit sailing...
    The intention was to "involve" kids from first stages of develpoment on a relative cheap hull,capable of "later improvements" (trapeze, spinnaker, & so on)
    There is no intention of developing a "class", no patents, no limitations on the way you sail, ot what stuff you get into the hull, just for fun & training.
    Attaching full set of plans & calculations done up to now, anyone interested, feel free to continue & improve from here up.
    cheers
    M
     

    Attached Files:


  10. wet feet
    Joined: Nov 2004
    Posts: 455
    Likes: 35, Points: 28, Legacy Rep: 124
    Location: East Anglia,England

    wet feet Senior Member

    The comment about a Merlin is correct in that they do have a lot of flare to achieve their considerable beam at deck level.If you take a look at http://www.bluelightning.co.uk/Merlins/hazard02.htm you will see a design from quite a few years ago that shows the hullform well.I shall continue to watch postings about this project with great interest.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.