Bilge on flat bottom boat

Discussion in 'Boat Yard Basics' started by Nick5288, Jun 17, 2015.

  1. Nick5288

    Nick5288 I Love!

    Has anyone made a bilge area that will channel water to a center location to be pumped out of a boat with a flat floor? I have some ideas but want to see if anyone has done it ..I don't get much water in but it's annoying to always be walking in some water that's never deep enough to pump out. Any ideas would be helpful thanks
  2. MBdude

    MBdude Still Standing

    I have same problem on my 14' flat bottom Stumpnocker. There is no way to make a well on it, unless I want a hump sticking out the bottom of the hull.

    The boat runs very level on plane and idle speed, which is good for draft, but not good for the water inside the deck. Your problem sounds the same.

    I have only one solution, and it is a product that I used for over 40 years to drain my boats, and it works great, IF, it fits your boat, it is the  Moeller Auto Flapper Drain Plug Set 51011-10, see

    I had a 1973 23' Formula, and later a 1984 30' Scarab over a period of 17 years, and using that same Moeller self bailing plug I never had to use or replace a bilge pump again.

    In order to install it on my Stumpnocker, I'll have to change the drain hole parts, as it has a Garboard type drain, and these flappers are designed for a 1" tube drain.

    The way it works is that when the bow goes up, the water drains to the back and out the drain, it is like a one way valve. In all my years of use, never once did it get something stuck in it and allow water back in.

    In the case of my Stumpnocker, because it is a flat bottom hull and it runs level, in order to get every last drop out of the deck,  I would have to knowingly make the effort to drain it by riding the boat bow high to drain the water, and also rock the boat from side to side to move the water from the sides into the middle drain. NOW, the boat bow can only be ridden high if I go slow, and being a flat bottom boat, it may not drain going slow. The only way to test it is to put a temporary drain plug (a rubber or soft wood stopper) on the inside and manually drain the boat and see if it works. If it does, then I'll change the drain plug design and buy the Moeller.

    Another benefit of the Moeller device was that it was left on the boat, and if it rained on the boat while it was on the trailer it would drain. AND you will never have to remember to install the drain plug, so, you can't sink the boat by forgetting to put in or take out a drain.

  3. MBdude

    MBdude Still Standing

    Here is my present draining plug system

    Here's a solution I just found so that I don't have to change my drain system. All I have to do is attach the flapper to a threaded pipe or fitting that has the same threads as the plug, and then zip tie the flapper onto the pipe. Though the I.D. of the drain hole would really be small, I don't think it will matter. (P.S- I'd also score the pipe and apply an adhesive and some small screws just to grip the pipe. I would not trust just a zip tie by itself.) By the way, they sell this part pictured, for like $40, what a racket!
  4. Brett

    Brett > PRO STAFF <

    Has anyone made a bilge area that will channel water to a center location to be pumped out of a boat with a flat floor?

    You don't want the sump to be centered on a flat floor.
    Better location is the rear corner of the cockpit or flat bottom hull.
    Why? Very difficult to get the water to the rear center of the flat floor.
    Very easy to get water to flow to a corner, simply by changing trim angle
    or body weight to that side of the hull. Same with the boat on the trailer,
    one side is always lower than the other, that is the side where the sump should be.
  5. DuckNut

    DuckNut Brandon, FL

    Put the drain plug in from the inside, get up on plane and pull the plug and out goes the water. Don't forget to put it back in before coming off plane.
  6. lemaymiami

    lemaymiami Well-Known Member

    As noted, flat bottomed skiffs don't drain very well (unless you have a floor or deck built in that's above the bottom of the hull... then you can build in a sump where your pump is actually sitting on the hull bottom). What I've done in the past is simply to install a pump right at the transom (offset as noted by Brett - but only with a slight bias off the center line -my preference...). The trick always to remember that the only way you're going to be pumping out is as you're moving up to plane with the bow up significantly - or simply to slow down until you just begin to drop off plane - you have to get your bow up in the air for your pump to work properly...

    As a matter of habit I learned to turn on my pump as I accelerated up onto plane then turn it off once the boat levels out and your pump has nothing to pick up.

    No, it's not an ideal solution but it will work (and as a guy who works out of skiffs that's enough for me....).
  7. MBdude

    MBdude Still Standing

    My boat is all flat, so, no sump is possible. Considering what you said, it would be better to put the drain plug assembly on one corner. Good idea, why don't the flat bottom boat manufacturers do it?

    My 2008 14' Stumpnocker has a fiberglass bulkhead/bench across the back that blocks all the water from getting to the stern because it only allows water to go through the middle, a place where the water never flows. Moreover, the two lockers forward of the bench also block the water into the sides, as the water never goes to the middle.
  8. topnative2

    topnative2 Well-Known Member

    water keeps the deck cool and washes off the is a friend
  9. devrep

    devrep Well-Known Member

    that's a very bad idea. zip ties will fail after being in the sun for a period of time.

  10. MBdude

    MBdude Still Standing

    That should be obvious, no one that keeps their boat in the water or in the sun should rely solely on a zip tie without monitoring it's condition. Moreover, when I used the duckbill by Moeller (which does not use a ziptie) for 17 years, I maybe kept the boat in the water for three days during any one year. The rest of the time it was out of the water.

    I don't keep my Stumpnocker in the water, so the Moeller device even if I only use the duckbill attached with a ziptie, would be OK, as long as one keeps an eye on it.  I still would not rely on just the zip tie. I would 5200 the duckbill onto the pipe fitting with threads, and maybe put a pair of small screws to add grip. Then I would put the ziptie or better yet a stainless steel hose clamp. All of which, does not take any extra effort to do.

    Here is another self bailing device that I think would serve as a backup if I attach the duckbill to this device as I just described above. If anything happens to the duckbill, this device keeps the water out by itself. I would only use this device if it is easier to attach the duckbill to it than to some other fitting, for it is overkill for me, since I keep the boat out of water:

  11. MBdude

    MBdude Still Standing

    Very true, on all my boats I always used 5 gal buckets to clean the decks. However, you want the dirty water to drain out, and that is what I hope we are discussing here.

    I had a 37' Hatteras Sportfish that had deck wash down pumps that washed the decks with saltwater. The darn pumps broke constantly, and they really had no pressure. It was a pitiful sight to see me wash the deck of blood after we hit a school of dolphin. Like a zombie I repaired the pumps two times, then I woke up and thought to myself, this is stupid, a 5 gallon bucket of saltwater does a better job and requires no fixing. If I really wanted to clean the deck quick, I would open cockpit transom door and back the boat into a wave and the entire deck would be cleaned spotless in 3 seconds. Of course everyone had to move their stuff off the floor. It was also a good way to get rid of anybody that was a pain. "My girlfriend is seasick, you need need to take her back to land",  Swoosh!