Seawater Strainer

Discussion in 'Boat Design' started by steve123, Jan 29, 2015.

  1. steve123
    Joined: Dec 2014
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    steve123 Junior Member

    Hi,
    Have a large aluminium sea strainer which has to be coated inside because of the S/steel mesh filter, any reason why it cant be an aluminium mesh filter ???
     
  2. BMcF
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    BMcF Senior Member

    It won't be around very long if made of aluminum and you are operating in salt water.
     
  3. gonzo
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    gonzo Senior Member

    I've never seen a sea strainer in aluminum. It is one of the worst possible metals for it.
     
  4. TANSL
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    TANSL Senior Member

    What material are the "aluminum sea strainer" you have seen ?. Would it be correct to assume that a "aluminum sea strainer" can only be aluminum?
     
  5. steve123
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    steve123 Junior Member

    The boat is made of Aluminium-Magnesium Alloy as is the sea strainer but the mesh filter is S/steel so we have to coat the sea strainer, hence the question.
     
  6. myark
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    myark Senior Member

    Attached Files:

  7. gonzo
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    gonzo Senior Member

    I often use plastic sea strainers. Never had a problem with them.
     
  8. steve123
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    steve123 Junior Member

    The guy in China is Noel...they dont do them big enough.
     
  9. myark
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    myark Senior Member

    The guys name is actually Hyde ..... who was also lost wax investment casting large keels made in stainless as well as rudders and shafts for sailing boats
     
  10. michael pierzga
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    michael pierzga Senior Member

    I dont like the idea of an aluminum strainer. Ive never seen one.

    Stainless is what Ive used. Epoxy primed and anti fouled.

    Plastic may be possible.. I have no experience

    Perhaps a plastic pipe with holes drilled.

    A fine screen works best
     
  11. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    There is no problem with an alu strainer body in an alu hull, but the filter element ("basket") in SS must be galvanically separated from the alu body. Depending on the design, this can often be achieved by adding suitable distance pieces.

    Note that rubber contains carbon, which is "lethal" to alu in salt water applications, so the isolators should be nylon or similar.
     
  12. gonzo
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    gonzo Senior Member

    Your comment about rubber is interesting and good to remember. I have often used neoprene under aluminum tanks. Searching what thickening agents are used, carbon is one of them. From now on, I will check. Thanks
     
  13. Ae Jae
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    Ae Jae Junior Member

    Good point about the rubber, got me thinking (nervously!) but I'm sure our seals were silicon. Our raw water inlets are bronze. I've changed to plastic baskets/liners as the old ones disintegrated. The plastic seems to last longer and would be less damaging to the impeller, if bits did come off.
    A
     
  14. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    I made a plastic sea strainer for a 1.25 inch Sendure Y strainer.

    It is a square flat piece punctuated full of squared holes made for crocheting? from Michael's arts and crafts.

    people run - hook yarns onto it, so it is a framework.

    It was a little stiff to roll, but a heat gun helped.

    I then stitched the edge together using copper wire. But you could use fishing line.

    I did that about 5 years ago, and it has worked flawlessly. Where we boat there is not really anything in the water, jelly fish could be sucked in I suppose. I have only ever seen some sea grass caught in it.
     

  15. viking north
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    viking north VINLAND

    I'm not sure of the size you require but one of the ships lifeboats I converted was an aluminum hull. I used an all plastic Vetus manufactured sea water strainer or as we call them here raw water strainers. It did however have a neoprene or soft plastic O ring but never ran into any problems with it.
     
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