lead in aluminium

Discussion in 'Sailboats' started by ted655, Aug 28, 2005.

  1. ted655
    Joined: May 2003
    Posts: 640
    Likes: 14, Points: 0, Legacy Rep: 122
    Location: Butte La Rose, LA.

    ted655 Senior Member

    If you put lead ballast in an aluminium keel, aren't you well on the way to making a battery? Add saltwater and something is going to errode. No?
     
  2. Cian Groves
    Joined: Sep 2004
    Posts: 31
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Australia

    Cian Groves Junior Member

    Make your keel into part of your fuel tank and run fuel around it.

    Cheers,
    Cian
     
  3. Raggi_Thor
    Joined: Jan 2004
    Posts: 2,457
    Likes: 64, Points: 0, Legacy Rep: 711
    Location: Trondheim, NORWAY

    Raggi_Thor Nav.arch/Designer/Builder

    People do that, and it seems to work OK, maybe because the top of the lead is covered with epoxy?
    When we attach a lead bulb to an aluminium keel, we make sure there is a layer of epoxy between the two metal parts.
     
  4. ted655
    Joined: May 2003
    Posts: 640
    Likes: 14, Points: 0, Legacy Rep: 122
    Location: Butte La Rose, LA.

    ted655 Senior Member

    Finally... back online. (hurricanes are a mighty force)
    Actually, I want to "fill" a hollow keel space. Pouring in hot lead prevents any coatings between the 2 metals. After pouring, the top could be coated to stop contact with bilgewater.
     
  5. Tim B
    Joined: Jan 2003
    Posts: 1,438
    Likes: 59, Points: 0, Legacy Rep: 841
    Location: Southern England

    Tim B Senior Member

    should be ok as long as it's kept dry everywhere (and that includes water seeming in from the outside of the keel.

    Or you could turn it into a ballast-water tank... as long as you coat the inside with epoxy first.

    Tim B.
     
  6. ted655
    Joined: May 2003
    Posts: 640
    Likes: 14, Points: 0, Legacy Rep: 122
    Location: Butte La Rose, LA.

    ted655 Senior Member

    Thanks. This is a Sharpie flat btm. A cubic foot of water weighs around 9lbs, a cu.ft. of lead is 700lbs., I need the space so I can't afford the tank size.
    I should be able to keep it dry if I epoxy the top.
     
  7. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    A cubic foot of water weighs a lot more then 9 pounds (you're thinking about a gallon). Try over 62+ for fresh and over 63+ for salt.

    There are several methods for isolating dissimilar materials. It shouldn't be a big concern.

    I wouldn't pour your lead in, but cast ballasting pigs of stackable and carryable sizes, that could nest in the keel. The lead will shrink when it cools and will likely cause wholesale plate distortion to boot. The pigs can be adjusted to trim out the boat during launch or if major changes take place (engine upgrade, etc.) These same liftable pigs can also lighten the boat by a substantial amount if stuck on the hard someplace far from a tow. Toss them over the side with a line and float. wiggle the lighter boat off and pick up your ballast again (it's cheaper then SeaTow) They can be fixed in place in a number of clever ways.
     
  8. ted655
    Joined: May 2003
    Posts: 640
    Likes: 14, Points: 0, Legacy Rep: 122
    Location: Butte La Rose, LA.

    ted655 Senior Member

    Good advice all around! Thanks, I will do as you suggest. Duh! I was thinking gallons, and... I should have caught it. The displacement formula was my clue.
    A fellow can't be handsom AND smart I guess. :D
     
  9. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I manage to struggle through some how. It's difficult being this handsome and smart too, but a burden I wear . . .
     
  10. JimCooper
    Joined: Feb 2005
    Posts: 81
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Varies, Aberdeen

    JimCooper Junior Member

    Ted

    If you want the metal experts to give you advice you should probably post in the metal boats area. I found that the experts tend to inhabit only certain areas of this forum.

    Your question was argued already by the knowledgeable laddies

    see the box:

    http://boatdesign.net/forums/showthread.php?t=5963&highlight=Aluminium&

    I have been aboard an alloy trawler that a roll of copper pipe ate several holes in her hull. I think lead would do the same if it was in contact.

    Cheers
    Jim
     
  11. JimCooper
    Joined: Feb 2005
    Posts: 81
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Varies, Aberdeen

    JimCooper Junior Member

    Ted
    I should hae said

    That area to post is

    Boat Design Forums > Construction > Boatbuilding > Metal Boat Building

    cheers
    Jim
     
  12. ted655
    Joined: May 2003
    Posts: 640
    Likes: 14, Points: 0, Legacy Rep: 122
    Location: Butte La Rose, LA.

    ted655 Senior Member

    Does'nt sound like a method was settled on. I'm thinking lead shot, poured into suitable lengths of PVC pipe, then fit into place is the answer. these little 6"dia "logs" would fit nicely into the space and there would be no contact between metals.
     

  13. MikeJohns
    Joined: Aug 2004
    Posts: 3,192
    Likes: 208, Points: 63, Legacy Rep: 2054
    Location: Australia

    MikeJohns Senior Member

    I just added an interesting observation to the thread/posts Jim refers to above.
     
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.