Shower, Head, and Sink Plumbing

Discussion in 'Boat Design' started by Capt. Flint, Oct 10, 2019.

  1. Capt. Flint
    Joined: Apr 2018
    Posts: 13
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    Location: Alabama

    Capt. Flint Junior Member

    Hey guys,

    So, I've come to the part of my build where I can play around with the living quarters. Attached is my proposed design, which is doable with the space that I have. I'm going to be adding a shower, relocating the head, and adding two sinks. Now, maybe it's because I'm tired, but I cant seem to find anything regarding advice or diagrams online about the plumbing for said additions. So, here are my questions:

    1) How should I go about adding two sinks? How would the plumbing be done for that?

    2) The head on the boat originally was just a standard household toilet that was centered where the shower will be. A more traditional marine head will be installed and relocated. So, How do I need to do the plumbing for that?

    3) Now for the real doozy, I want to add a shower. I've looked and I cant seem to find anyone that sells shower stalls for boats. If anyone knows of a company that does, then please comment the link. Anyhoo, I'm not real sure on how to go about making the shower. The only thing I can think of is to do the walls and flooring with plywood and epoxy over it, I guess fiberglass could work too. I can figure that part out, it's the plumbing part that I really need help with. I know "grey water" & "black water" cant be stored together, so that will require two tanks. If anyone has a diagram for a shower setup that would be great. Also, only part of the floor will have wood slits where the drain is located.

    **I don't want the head and shower in the same room**

    Thank you all for your comments, suggestions, and advice.

    - Flint

    Attached Files:

  2. Capt. Flint
    Joined: Apr 2018
    Posts: 13
    Likes: 0, Points: 1
    Location: Alabama

    Capt. Flint Junior Member

    Here's where I got the idea for the shower, including the partial wood slit floor.

    Attached Files:

  3. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Most grey water is drained overboard. Even in most ndzs, shower and sink water go over the side.

    However, you still want traps or mosquitos will invade.

    Showers present another problem. Drainage through the floor with a trap only works with access. And typically, shower bases are higher than the surrounding floor, so you can install a drain in the raised floor.

    I purchased the Whale Shower IC which will go to a sump then up n out.
  4. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Could you maybe post a photo or two of the boat that you are working on, including a photo inside the hull (even if it is presently just an empty shell)?
    And list her approx dimensions (they are not too obvious from your sketch).
    Is there an absolute requirement in your home waters to have a holding tank for grey water? If not, then it might be easier to send it over the side via a through hull fitting.
    If there is, then you can have the drains from both sinks going to the holding tank.
    You should then be able to discharge the grey water holding tank out at sea. You would probably need a pump for this - a manually operated bilge pump would work.
    If the grey water tank is fairly low down (in the bilge?) then you could have gravity feed even from the shower to the tank.
    If you do not need a grey water tank, then you will still need to have a pump to pump the shower water overboard from the shower sump - it is not very wise to just let the shower drain into your main bilge.
    Re a holding tank for the toilet - because you will be pumping from the toilet to the tank, it would be useful if you could mount the tank fairly high up (say in a locker) so that when the time comes to empty it out at sea, you can just open the sea cock on the through hull fitting and drain it overboard. If overboard discharge at sea is not allowed then you will need to have a deck fitting where it can be pumped out at a shore station.
    Re your shower, would any of these be suitable?
    RV Showers - CAMPERID.COM
    Re not wanting the head and shower in the same room, it looks like you have a bulkhead between the shower and the heads compartment.
    Have you got room for a door on the heads compartment, or would a curtain work ok here?
    Capt. Flint likes this.
  5. Capt. Flint
    Joined: Apr 2018
    Posts: 13
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    Location: Alabama

    Capt. Flint Junior Member

    If I were home, I'd take a few pics for you...I do however have a picture from when I first bought her, the lower forward cabin is smaller in her original state. I've lengthened it for my needs. Her total length is 38'8" and 3/8 of an inch, she's 12.5ft at here widest point, and in the new lower cabin there is a total length of 16ft even. Sorry, I didn't realize that I left dimensions off the drawing; I just had everything planned out in my head.

    If I don't have to have a holding tank for the grey water, then I wont have one. I was under the impression that you had to have one. Trust me, I wasnt going to just let the water drain into the bilge. And you're correct, that is a bulkhead between the shower and head compartment. There will be a door right next to the toilet facing port, the closet will have a door facing starboard, and the shower will have a door facing aft. I didn't think to add those either since I know where they are in my head.

    In the picture of the lower cabin with the old house toilet, the wood panels that slope inward have been removed in order to have more room.
    IMG_5433.jpg IMG_9738.jpg IMG_7655.jpg
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    You can buy a fiberglass shower box from Homedepot and cut the top to fit the deck crown. I've used them several times in new construction and remodels.
    Capt. Flint likes this.

  7. BKay
    Joined: Jan 2011
    Posts: 34
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    Location: Reedville, VA

    BKay Junior Member

    Just a thought - what if you relocated the sink to where the closet is now? Put a door on the compartment that houses the head and have the hinges on the aft portion and have the door width be such that it could swing open and cover the full span of the sole, so when you open the head the door closes off the forward portion of the entire area. Now you can sit on the toilet and your feet will be on the area that was previously the passageway.

    If you wanted, you could do the same thing with a door to the sink compartment, except have it hinged on the forward portion, so when it is open it would close off the shower. You could certainly mess with where the hinges are located and which compartment would open and result in closing off different sections.

    Regarding the shower, I think that would be a tough shape to find an existing shower stall for. Since it's a wooden boat, you might need to custom build something that allows the hull to flex separably from the shower stall, but keeps the water where you want it. Air circulation will be important as well to discourage rot from the fresh water in the shower.

    On a boat this size, I'd skip the gray water tank and just have a black water. You can have a sump under the sole with a strum box that catches the shower (and sink water for that matter) and pumps it directly overboard.
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