"Hard Chines"

Discussion in 'Boat Design' started by DaveK, Dec 1, 2005.

  1. DaveK
    Joined: Dec 2005
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    DaveK Junior Member

    I picked up an old boat that has been stored on a trailer for the last 25 years. The trailer pads have left indentations in the hull and those will be filled with Kitty hair along with other minor hull repairs, and then painted. This boat is pretty fast as is but, very unstable and hard to keep on her feet. I've observed other older hull designs and most seem to have "normal" curve shape. Finn, Thistle, lasers and others.

    My question is should I consider rounding the chines a bit to add stability?? Or will it be best to leave as is. I'll be doing a lot of work with the kitty hair and gel coat so, smoothing things as I go won't be a ton of extra work. I'm experience with working fiberflass just, wonder if its worth it???

    Here's some photo's and thanks for any advise!!
    DaveK

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  2. nitz
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    nitz Junior Member

    I'm not sure but i think it'll be more stable with the chine than without it.
     
  3. tom28571
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    tom28571 Senior Member

    From the first 2 photos, I thought it was a Windmill sloop but the last one says that it is likely a US1 which is a cut down cat-rigged Windmill.

    That is a terrible way to support a boat on a trailer. The trailer bunks should support the keel and chine. Full width transverse bunks are best for this kind of bottom. Rounding the chines, which would be the worse job you ever took on, would decrease the stability, not increase it.

    This is a pretty good boat. Just get more time in it. Any small performance boat is going to be tender.

    I once fixed this kind of dimple on a Laser by pressing the dimple out from the inside and strengthening on the inside. A lot less work than fairing the outside. Adding heat helps.
     
  4. DaveK
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    DaveK Junior Member

    I wish I had photos of how it looks now... trailer & boat. But,they are on the home PC.

    The boat was stored this way (bunks in the middle) forever!!! I have since moved them to the very outside and revamped the whole trailer. Thanks for the advise!! I was reading the "my boat" thread and folks had mixed feelings on his chines and I wondered about mine befor I even read that.

    BTW, this boats hull is an exact copy of a windmill. At least, I was told that.

    Thanks Again
    DaveK
     
  5. h_zwakenberg
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    h_zwakenberg HullDrag/32 programmer

    if you round the chine, you remove displacement where it would have contributed to lateral stability, so I reckon you shouldn't remove anything. It will get even more unstable, if only a little bit...

    bye
    Hans
     
  6. DaveK
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    DaveK Junior Member

    Thanks HZ....

    I had just been observing older hull designs (of popular boats) and none have hard chines. So, I thought about it and now... Thanks to ya'll, I'll leave it the way its meant to be.

    DaveK
     
  7. tom28571
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    tom28571 Senior Member

    By "cut down" Windmill, I meant that the freeboard (height of the sides) was reduced quite a bit. You are correct in that the hull of the US1 was actually molded directly off an existing Windmill.

    I've never sailed or even seen a US1 but have many hours in Windmills. They are great boats and the US1 should be exciting single handed sailing.
     
  8. DaveK
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    DaveK Junior Member

    Thanks Tom!!

    I wish I could find some pics of the windmill. The only one I came up with is here and it doesn't show any details. But, I can see that the freeboard is much higher.

    http://www.sailingtexas.com/swindmilla.html

    The main problem with the US1 is that, any slight over heeling will take on a ton of water. Where you would sit on the leeward side digs in. This is the root problem of the design. And as you pointed out, a cut down freeboard, lends itself to this issue. I thought perhaps it was tripping over the hard chine and then digging in. I know... a lame guess at it.

    Thanks again and you have any Windmill pics, please send 'em my way.
    DaveK
     
  9. tom28571
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    tom28571 Senior Member

    Go to: http://www.windmillclass.org/ for all you want to know about the Windmill.

    I have some stuff on "The Builder's Corner" page.

    I cannot say much about the lee chine digging in on the US1. I guess the solution is to sail it flat which is good advice in any boat. Will give you great "abbs" too. Luffing the main through the gusts will help also.

    Edited to say that I meant to say lee rail instead of chine above.
     
  10. DaveK
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    DaveK Junior Member

    I'm not sure about the great abbs thing........ I took it out in 20+ winds yesterday. My whole body is in pain today except, the abbs. Boat screams on a reach and down wind. But, lots of luffing up hill.

    Thanks a bunch for that link! Lots of info there and it makes me kinda wish I had bought a windmill. Seems to be a great heavy & light air boat. Rigging ideas are also helpful there. My vang and outhaul snapped into peices on seperate ocassions yesterday. You know something is going bad when you hear that loud ominous bang.

    Thanks again Tom!!
    DaveK
     
  11. DaveK
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    DaveK Junior Member

    Also... just for grins!! I hated the first photos I posted!! They were right after I picked it up after being in storage (outside) for 25 years.

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  12. tom28571
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    tom28571 Senior Member

    Pain or not Dave, I think you are going to have a ball with this boat. If you can stay upright in 20 kts, everything else will work itself out. Good luck.

    Some of the boats on that site are mine. I did the design work to convert the plank on frame to wood/epoxy/glass construction in a female mold. "Harbinger", sailed by my son Mark, shows up several times. Had a real great feeling last summer at the Nationals when the first three boats across the line in one race were wood and built to my design. They crossed the line banging the sides of their boats and chanting "wood, wood, wood".:D :D :D First time that had happened in a National Championship race since F***@@@s took over in the late 1960's.

    Who needs F***@@s?:cool: :cool: :cool:
     
  13. Brent B
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    Brent B Junior Member

    Work on the sail too...

    To my sailmaker's eye, that sail looks somewhat too deep. Perhaps you could get it flatter with a lot of outhaul and mast bend. OTOH, a good sailmaker could probably recut it, giving you a faster sail with less heeling.

    Brent
    Benson Sails
     
  14. tom28571
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    tom28571 Senior Member

    Brent, I thought that when I looked at it also. Of course a single hander sail should have a deeper chord than a boat with a jib. Being Mylar, it's not going to respond as well to adjustments as Dacron. Can't tell how tight the outhaul is though.
     

  15. DaveK
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    DaveK Junior Member

    The sail is another whole issue. Its a brand new sail!!! I sent pics (to sail maker) of the issues I have and am in the process of trying to work it out. Increasing outhaul and cunnigham to the max yesterday help but, still not good. That's why outhaul broke!!! I believe its a symptom of mast bending and am not sure what else I can do........ maybe stiffen mast?? I got to call the loft tomorrow. Bummer.

    I didn't post this before cause, I didn't want to see how bad it is....lol. Down wind, its a great sail.

    [​IMG]
     
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