keelmaterial for an alu sail boat!

Discussion in 'Materials' started by nukisen, Oct 25, 2009.

  1. nukisen
    Joined: Aug 2009
    Posts: 440
    Likes: 8, Points: 0, Legacy Rep: 124
    Location: Sweden

    nukisen Senior Member

    Hi all!
    I am planning to build a small aluminium sailor.
    though I do want the keel to have a higher dens. then aluminium.
    Of course I dont want the alu to bee corrogated by galvanic streams.

    Any suggestions of a good material! Not to expensive of course.
    The keel is still under design and should be a little deeper and a little bit shorter. The same opt. with the rudder.
    The data in the pdf file isn´t correct.
     

    Attached Files:

  2. Ad Hoc
    Joined: Oct 2008
    Posts: 7,077
    Likes: 1,010, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Have you done any calc's, to confirm that you actually need a higher density material, for your righting moments?
     
  3. nukisen
    Joined: Aug 2009
    Posts: 440
    Likes: 8, Points: 0, Legacy Rep: 124
    Location: Sweden

    nukisen Senior Member

    Yes i do have a righting moment of about 0.47 knewton at 60 degrees. And i am not sure how much a sail does press the boat at the side. I do have a vert cog about 0.45 with myself placed on the durk. I am sure that you meant the boat boat to be as light as possible. And the hull is about 20kilos at the moment. If I do use Alu. The vertical Km is about 0.67meters above lowest point at bottom (without keel inkluded).
     
  4. gonzo
    Joined: Aug 2002
    Posts: 15,441
    Likes: 1,013, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    A lead filled aluminum keel can work. You can cast the lead to the shape of the keel and set it in epoxy.
     
  5. nukisen
    Joined: Aug 2009
    Posts: 440
    Likes: 8, Points: 0, Legacy Rep: 124
    Location: Sweden

    nukisen Senior Member

    Yes Gonzo!

    Actually I did have this in my mind. But I wasn´t sure about the galvanic. But you mean this wouldn´t bee any problem to corrugating the alu in salt water.
    Of course I will use alu Aw 5754 wich is saltwater resistant.
     
  6. nukisen
    Joined: Aug 2009
    Posts: 440
    Likes: 8, Points: 0, Legacy Rep: 124
    Location: Sweden

    nukisen Senior Member

    Ad Hoc!
    I also have to calculate the sail before I make the boat heavyer.
    thx!
    Janne
     
  7. gonzo
    Joined: Aug 2002
    Posts: 15,441
    Likes: 1,013, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The lead and aluminum will not touch if the lead is encapsulated in epoxy
     

  8. nukisen
    Joined: Aug 2009
    Posts: 440
    Likes: 8, Points: 0, Legacy Rep: 124
    Location: Sweden

    nukisen Senior Member

    Ah oki!
    Then I can use any material as I want.
    :)
     
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.