Water Channel

Discussion in 'Construction' started by Evil Joker, Sep 28, 2007.

  1. Evil Joker

    Evil Joker Member

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    I'm working on a water challenge for a Kunig. Is there a certain weighth and how would you suggest best construction of a water channel. Pictures would be much appreciated. I like to hear & see other people's techniques.
    Thanks
     
  2. Evil Joker

    Evil Joker Member

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  3. the frog

    the frog Member

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    better living with chemicals,
    I have been using self leveling polyurethane concret sealant for all my boats. simply level hull front to rear and depending on size pyt 2 or 3 tubes of the sealer into the bottom about 3/8 deep at center.after a coupl of days take a box cutter and cut whatever channel you want.it will pull up like a large rubber strip.
     
  4. rowboat captain

    rowboat captain Member

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    So there is no rule about putting floation into your boat?

    anyone use anything else like great stuff foam?
     
  5. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    As long as it sinks when it gets full of water, you can put almost anything in it.
     
  6. Anachronus

    Anachronus Well-Known Member

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    As long as the sealant is denser than water it will sink.
     
  7. rowboat captain

    rowboat captain Member

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    can you epoxy over the self leveling polyurethane concret sealant or will the expoy eat it.

    also how deep do you make your water channel?
     
  8. Bob

    Bob Well-Known Member

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    I make the water channel deep enough to help the pump prime with less water in the hull, about 1/4". In the bow 4" or so and the stern 4" or so make higher, almost to the bottom of the open window. Make it 1"-2" wide. Too much water channeling will make the bottom of your ship light and when the water gets in it will raise the center of gravity, tipping your ship over before all the reserve boyance is gone.
     
  9. Kotori87

    Kotori87 Well-Known Member

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    I've always figured it's better to have a narrow and deep water channel than a shallow and wide water channel. The deeper it is, the better your pump will prime and the faster it will reach full capacity. The narrower it is, the less water (read less dropping in the water, AKA less above hits becoming belows) it takes before your pumps turn on.

    I personally like to build the water channel as a twin-keel setup in scratchbuilt wooden hulls. It's not easy but the result is pretty cool and effective.
     
  10. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Narrow and deep (not always easy to do while keeping a low center of gravity) is better from a fluid flow standpoint. More cross-sectional area away from the walls/top/bottom = better flow in the channel.

    Unfortunately, it's hard for me to get a lot of height in the channel. I like my battery low in the hull.
     
  11. JohnmCA72

    JohnmCA72 Member

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    Batteries will displace water ;-). I always make a "cutout" in my water channels to fit the batteries. It gets the batteries as low as possible & also helps keep them from moving around.

    JM
     
  12. Evil Joker

    Evil Joker Member

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    Okay
    How about the water channel starts at 1 inch in the front and in the back it is an inch 1/2, inch 3/4 in the back?
     
  13. Evil Joker

    Evil Joker Member

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    it would keep the water moveing to the back ( that is width ofcourse )
     
  14. JohnmCA72

    JohnmCA72 Member

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    I think that the effect of "flow" within a water channel is highly overrated. One of these days, I want to build a see-through research ship, just to see for sure. What I believe to be the benefit is to have a smaller area, lower, so that a given volume of water ends up having a higher level than if it were spread out over a larger area. This allows the pump to prime easier. I think this idea of water "flowing" down the channel like some sort of mini river is ridiculous, the way ships bounce & pitch all over the place, but have no proof. I think that all you really need is a "well" for the pump. Water will find its way to the lowest point - it doesn't need to be directed.

    JM
     
  15. djranier

    djranier Well-Known Member

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    I think you are right as long as the ship is sitting level in the water, a well would work better. I notice going in reverse that my pump looses suction since all the water is flowing down the channel towards the bow. I think a well about twice the size of the pump housing so that the water can pool would be about the best. In my new VU thats actually what I'm going to try.
     
  16. crzyhawk

    crzyhawk Well-Known Member

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    I've always thought that the primary purpose of the water channel was to drive the water to the center of the ship (my water channel is angled down towards the center for this reason) and prevent listing. Trim of the ship provides the location of where the water pools...for me forward, for MOST others aft. Keeping the ship on an even keel (in my humble opinion) is what is most important, as listing ships pumps aren't very efficient regardless of how the water channel is set up.

    As for pump placement, I am in the minority of people who has a forward mounted pump, and I like it that way. Why? I have a LOT more reserve buoyancy up there. I balanced her to be a bit bow heavy so the water will naturally flow there. At treaty speeds, acceleration is less of a force to push the water backwards (I've seen more ships sink because they made the fatal mistake of moving forward at the wrong time which forces the water aft where there is very little buoyancy) so my water stays up near my pump. If necessary, I kick reverse a little and let the water shift physically. After seeing how well this set up works for me, I'd never consider moving my pump aft. Most fast gun guys will tell you my set up is awful, so take my set up for what you paid for it. I'm just saying it works for me and I like it.

    On my Salt Lake City, I will have the pump mounted aft. She's got a flush deck, so there is no spare buoyancy at the bow, and she's a bit faster then my Invincible, so will have more acceleration to push water back. Different ship designs and performance; different damage control layout.

    Mike D
     
  17. CURT

    CURT Well-Known Member

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    Water channelling has different effects on different hull shapes. I find if your ship has a flush deck hull best place to for the pump is back aft. If your ship has a low quarterdeck generally you can't fit a large pump back far enough to be effective so having it forward where there is more hull height and buoyancy will keep your ship afloat longer.
    I tried narrow and very wide channel. I like somewhere in between about 1.5 to 2 inches again depending on the hull width.

    My Yamato allows water to be channel or flow down the sides of the hull if the water is entering through hulls through the midships section of the hull body. Near the bow the water is forced to the center of the ship through angled foam channelling to guide water flow to the center and straight to the pump. I have a wide area around the pump to allow the water to pool but keep the pump primed.

    I found that some ships had waterchannelling so tight to the hull sides that it took quite a bit of water to pool before it overflowed and reached the center or it took too long for the water to flow to the center of the ship. I like to have the water start dispersing itself immediately and not pool in any one location. All my ships when flooding remain on an even keel no matter where the holes are concentrated on the hull.

    Short small ships with low quarterdecks should have the pump forward in the bow. Larger ships with loq quarterdecks generally can last longer and make use of the pump back aft if their hull is deep enough.

    Too little channelling and the water will swish around the bottom of the hull. I like to have small mini channels or slots cut in between the main channelling angled and pointed towards the center but back aft. This ensures the water will flow directly and quickly to the center. The best way to test your channeling is to prop your hull on an angle and using a garden hose send a stream of water starting at the bow and watch how the water flows through your channelling. Try again from the stern. Tilt the model on it's side at various degrees of list with a little downangle at the bow and the stern to see the effect it has on water flow. That way you can be sure if your water channeling is effective or not.

    I tried this on the Roma and it worked great. You can't really picture water flowing through your hull when the ship is out on the water. This way you visual can gauge how it works.

    [:D]