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  1. #1
    Join Date
    Jan 2005
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    677

    Default Secondary Bilge Pump connected to galley outlet

    Hi everyone!

    I'm looking to the wisdom of the panel for this bilge query.

    I've got a primary bilge pump already that's manual and has it's own dedicated outlet above the water line and is operated from the cockpit.

    I've also got enough spare pipe, a freebie Rule 500, a separate automatic switch and a spare one way valve from a project from a previous boat.

    I don't want to tap into the primary bilge pump outlet for this as the Rule 500 has a smaller diameter pipe (19mm) than the big manual (38mm I think) as I like the idea of having a single dedicated bilge pump.

    I'm thinking of connecting the small rule 500 to the 19mm pipe, placing the one way valve near the pump and creating a loop that's connected to the galley outlet via a diverter valve. By using the diverter I prevent any water coming back into the sink. The loop checks any errant water flow and failing that I've got the one way valve as my last line of defence.

    By the way the galley outlet is below the waterline and currently only has a seacock on it and no loop (seacock closed when underway).

    This secondary bilge pump is only for keeping the bilge dry whilst I'm away from the boat that's it. For anything serious I use the manual big boy bilge pump.

    I think it's a valid approach as I really don't want yet another hole in my hull. In addition, as I have a low freeboard whatever tack I'm on with the outlet present will have the same problem of water coming up the pipe. I did think of feeding the outlet to the cockpit.

    However, there are two outlets one is on the deck going to below the waterline. The others are at the base of the seats these are above the waterline but not by much and may suffer the same problem of water coming back or being added into the bilge.

    What does the panel think?
    Last edited by Captain Haddock; 16-04-12 at 00:12. Reason: Hit submit to quickly!

  2. #2
    Join Date
    May 2003
    Posts
    54,243

    Default

    Quote Originally Posted by Captain Haddock View Post
    Hi everyone!

    I'm looking to the wisdom of the panel for this bilge query.

    I've got a primary bilge pump already that's manual and has it's own dedicated outlet above the water line and is operated from the cockpit.

    I've also got enough spare pipe, a freebie Rule 500, a separate automatic switch and a spare one way valve from a project from a previous boat.

    I don't want to tap into the primary bilge pump outlet for this as the Rule 500 has a smaller diameter pipe (19mm) than the big manual (38mm I think) as I like the idea of having a single dedicated bilge pump.

    I'm thinking of connecting the small rule 500 to the 19mm pipe, placing the one way valve near the pump and creating a loop that's connected to the galley outlet via a diverter valve. By using the diverter I prevent any water coming back into the sink. The loop checks any errant water flow and failing that I've got the one way valve as my last line of defence.

    By the way the galley outlet is below the waterline and currently only has a seacock on it and no loop (seacock closed when underway).

    This secondary bilge pump is only for keeping the bilge dry whilst I'm away from the boat that's it. For anything serious I use the manual big boy bilge pump.

    I think it's a valid approach as I really don't want yet another hole in my hull. In addition, as I have a low freeboard whatever tack I'm on with the outlet present will have the same problem of water coming up the pipe. I did think of feeding the outlet to the cockpit.

    However, there are two outlets one is on the deck going to below the waterline. The others are at the base of the seats these are above the waterline but not by much and may suffer the same problem of water coming back or being added into the bilge.

    What does the panel think?
    the pressure from the pump is likely to cause water to rise up into the sink.

    i made up a 38 x 38 x 12 m/m tee with a 90 deg 12 m/m elbow (pointing up stream) inserted into the manual pump pipe on the down side of the high loop into the skin fitting.

    hope that is clear
    I may be wrong but not always

  3. #3
    Join Date
    May 2007
    Posts
    15,275

    Default

    IMHO bilge pumps should be independent.

    BUT it depends what you are using it for.
    Is it to be automatic? perhaps to deal with rain water?, in which case it will need to operate unattended, without switching diverter valves etc.
    Or is it for crisis use, in which case a diverter valve on the sink outlet is fine, it will never be used unattended, so back flow when the oneway valve gets a cornflake in it won't sink the boat.

    I'm with RORC. Every serious yot needs two independent, manual pumps as a minimum.

    Bear in mind that the flow rate of Rule type pumps drops fast when working against a head of water or a long hose.

  4. #4

    Default

    I think leaving the sink outlet seacock open while you're away from the boat just so you can use it for an automatic bilge pump is daft; where would you be if that seacock sprung a leak?

    How about running the outlet into your cockpit and let the water run out the cockpit drains? Might be a bit messy but avoids the unwanted through-hull.

  5. #5
    davidej is online now Registered User
    Location : West Mersea. north Essex
    Join Date
    Nov 2004
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    2,105

    Default

    In had a similar dilemma on my last boat.

    I never had any significant amount of water in the bilges but, being b/k with no central sump, even a little bit of water would slosh around and the manual pump did not get it out.

    To remove the last few cc's, I installed a rule pump, and when needed, I pumped it into a bucket and thus avoided the complications of extra outlets, y- joints, non-return valves etc
    davidej

  6. #6
    rob2 is offline Registered User
    Location : Hampshire UK
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    Aug 2005
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    3,060

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    I have to agree that an unattended pump needs to go to a hull fitting above the waterline. if you have a suitable outlet, you should tee into that.

    Rob.

  7. #7
    yoda is offline Registered User
    Location : Nic 345, Tamar river, Devon
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    Dec 2001
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    While others have valid points about leaving a seacock open at the mooring I see no difference between this and the cockpit drains which are open all the time. I believe that an automatic pump as you propose is an excellent idea and has the ability to save untold damage. I have just fitted a similar arrangement! the detail looks good to me.

    Yoda

  8. #8

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    Quote Originally Posted by yoda View Post
    While others have valid points about leaving a seacock open at the mooring I see no difference between this and the cockpit drains which are open all the time. I believe that an automatic pump as you propose is an excellent idea and has the ability to save untold damage. I have just fitted a similar arrangement! the detail looks good to me.

    Yoda
    All the cockpit drains that I'm aware of are above the waterline; they are effectively like gutters on your roof and stop water from the outside getting in. A very different thing indeed.

  9. #9
    prv is online now Registered User
    Location : Southampton
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    Nov 2009
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    18,604

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    Quote Originally Posted by agurney View Post
    All the cockpit drains that I'm aware of are above the waterline; they are effectively like gutters on your roof and stop water from the outside getting in. A very different thing indeed.
    Cockpit drains on most boats exit below the waterline; it's only on newer boats with shallower cockpits and possibly open transoms that they come out above the water. The usual setup is a couple of plugholes in the cockpit sole, a pair of seacocks in the bottom of the hull, and some stout hose between the two. And as Yoda says, these seacocks have to stay open when the boat is unattended.

    Pete

  10. #10
    mitiempo's Avatar
    mitiempo is offline Registered User
    Location : Victoria B.C. Canada
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    Nov 2009
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    801

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    I believe each bilge pump should have its own dedicated outlet, not shared with another bilge pump or complicated by sharing it with a sink outlet.

    I agree with most bilge pump manufacturers who recommend there not be any non-return valves in the outlet. They reduce flow by a significant amount.

    A Rule 500 is a maintenance pump, not for crisis use - well for a very small crisis maybe.

    My boat also came with a manual pump only, operated from the cockpit.

    My solution for maintenance was a Rule 500 automatic pump and I installed a non-return valve immediately after the pump. The exit is in the cockpit, just under seat level and directly over a cockpit drain. A hose takes the water down to an inch or so above the drain. If I am sailing I know immediately when the pump is active.

    I am installing another pump a bit higher and with more capacity and without the non-return valve. It will have a dedicated outlet in the transom with a high loop just before the exit point.
    Brian
    Afloat in Victoria B.C.

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