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Cockpit Drain Pump System


harbday

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Cockpit drainage and wet feet is a topic that has been discussed at length on this and many forums.  My 1806v has self-bailing thru-transom drains which usually sit below the waterline.  Even with rabuds, there are situations when standing water pools in the cockpit.  This is especially annoying during long stretches of fishing between self-bailing while underway.  I have what may be a very stupid idea and figured some of you would enjoy telling me as much.

My thought was to add cockpit deck drains that feed directly into a pump/macerator in the the bilge.  Water would discharge out the existing bilge line via a 3-way connector with a check valve.  The pump would be switch-controlled separate from the existing bilge pump.  I figured I could use deck drains that can be plugged if needed and connect them directly to a cutoff valve in case a hose fitting breaks or for any other reason that I wouldn't want water getting into the bilge.

I hate drilling holes in my boat and especially in the deck, but the addition of a second bilge makes me think that this system could be a net positive.  The fact that I haven't been able to find anyone doing something similar online says otherwise.

I'd love to know why this may be a bad idea.

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Harbday,

I guess I'll go first.....not a bad idea! If the feature you want is the ability to make a decision as to when to drain the swamp with a switch on the switch panel, that will do it. Unless you have some way to sense water presence in the cockpit, it won't be automatic, keeping feet dry all the time.

Why not drain direct into bilge, and let that pump do the work? I'm sure you will have a pump capacity problem, necessitating a "super bilge pump". If not direct drain into the bilge, the additional cockpit pump will have to be super also. Don't underestimate the possible amounts of water to pump overboard. I've emptied 10 gallons from a bucket into the bilge, and was surprised how long the bilge pump took to pump overboard.

Either way, you also have eliminated the ability to "automatically" drain the cockpit under way. I'm not sure I'd want to lose that.

Seems to me the real solution is still to solve the "age old" problem of intrusion in the first place, but other than rabuds, nothing has come to market yet.

I think you're like me. I lie awake at night trying to make my boat perfect! A labor of love! And a lot of fun. Let's all chip in, and tweak this to make it work!

Good job!

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Thanks for the reply Frozen.  You are spot on about my love for perfecting my rig and the resulting lack of sleep.

10 hours ago, FROZEN said:

If the feature you want is the ability to make a decision as to when to drain the swamp with a switch on the switch panel, that will do it. Unless you have some way to sense water presence in the cockpit, it won't be automatic, keeping feet dry all the time.

This is exactly what I am going for.  I thought about putting some sort of float switch above deck in the cockpit to make it automatic.  I keep a lot of gear in the back so I would  have to find somewhere to mount it so it wouldn't get broken.  Johnson makes a small electric sensor float switch that looks like it would work although I've been told they are not very reliable.

10 hours ago, FROZEN said:

Why not drain direct into bilge, and let that pump do the work?

I found too many posters on other forums citing cockpit drainage directly into the bilge as the fatal design flaw that sunk their boats.  My bilge stays pretty dry and I leave my boat in the water over the weeked fairly often.  I'd hate to completely rely on a bilge pump and float switch that could always fail. 

10 hours ago, FROZEN said:

Either way, you also have eliminated the ability to "automatically" drain the cockpit under way. I'm not sure I'd want to lose that.

I think I would still be able to "automatically" drain the cockpit underway the same way I do now.  Correct me if I'm wrong, but unless the pump is switched on, wouldn't the water only fill the drain lines up to the pump intake and any water left above the deck would flow through the existing stern drains?  I think I would only lose this self-bailing ability if I drained directly into the bilge.

 

This is a photo of someone else's 1806, but you can clearly see how the existing stern drains are set-up to flow directly through the transom (unlike the bigger PFs which I think go through the floor then out the transom?)

 

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Could you add another discharge line so you can have two independent systems?  If you could it would not tie up you bilge line if something were to happen.  Maybe have the "new" deck drain go to a sump below deck and pump from there if there is room?  That would make it simple to add a float switch.  I have never been on a 1806 so just thinking out loud.

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Harbday, I applaud your initiative to remedy an age old problem and we can tell you put some thought into the solution.  However, I think your original idea has some flaws. Right now, any water that enters the deck will eventually drain overboard even if you get we feet. To drain the same water into the bilge area is asking for problems. One problem is the one-way-valve. These little valves are very sensitive to particulate matter. So, if you get any amount of grass, fishing line, scales or whatever in the valve, it will remain open and water will freely flow both directions.

The sump idea (below deck) has some merit, but what happens if you have a problem with the pump, wiring, fuse, switch or battery? Where does the water that accumulated in the sump go? The only solution that comes to mind, is to cut and area out of the floor, near the transom and make a sump area that is sealed from entering the bilge, then add an automatic bilge pump. Any water that enters the sump will be pumped out and if there is any malfunction of the system, the access water will flow out of the transom drains as usual.

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Thanks to everyone for the thoughtful replies so far.

2 hours ago, mulligan said:

Could you add another discharge line so you can have two independent systems?  If you could it would not tie up you bilge line if something were to happen.  Maybe have the "new" deck drain go to a sump below deck and pump from there if there is room?  That would make it simple to add a float switch.  I have never been on a 1806 so just thinking out loud.

Adding a second discharge line is definitely possible and probably the best way to do it.  I have added the TH Marine big square hatch so the sump with auto bilge might be possible.  I agree this would add another level of protection against water getting into the bilge area.

2 hours ago, SCFD rtrd. said:

Harbday, I applaud your initiative to remedy an age old problem and we can tell you put some thought into the solution.  However, I think your original idea has some flaws. Right now, any water that enters the deck will eventually drain overboard even if you get we feet. To drain the same water into the bilge area is asking for problems. One problem is the one-way-valve. These little valves are very sensitive to particulate matter. So, if you get any amount of grass, fishing line, scales or whatever in the valve, it will remain open and water will freely flow both directions.

The sump idea (below deck) has some merit, but what happens if you have a problem with the pump, wiring, fuse, switch or battery? Where does the water that accumulated in the sump go? The only solution that comes to mind, is to cut and area out of the floor, near the transom and make a sump area that is sealed from entering the bilge, then add an automatic bilge pump. Any water that enters the sump will be pumped out and if there is any malfunction of the system, the access water will flow out of the transom drains as usual.

I think its easiest to think about it like you would a livewell set up instead of a traditional bilge pump system. The water in the cockpit is the ocean. The deck drain is like your livewell thru-hull intake scoop which is normally connected to a seacock. From there, water is sucked through the drain line directly through the intake port of a livewell pump with a strainer or a macerator pump and then pushed out the side hull bilge discharge line.

Unless there is a drain/hose fitting failure, I'm not sure how water would get into the bilge. Correct me if I'm wrong, but unless the pump is switched on, wouldn't water only fill the drain lines up to the pump intake and any excess water would be left above the deck to flow through the existing stern drains? I thought the pump would act as something of a third valve to prevent free-flow of water through it unless it is in the on position. If I am right, then I think any pump failure would leave me in basically the same position I am in right now

I am envisioning three points where water could be prevented from moving through the system:

  1. a removable plug at the deck drain (think old bathtub style)
  2. a ball valve or seacock connected directly to the deck drain
  3. the pump itself when in the off position

If I am wrong about this point, that would be the design flaw I was looking for that would make this a bad idea.  As you said, the sump would be a potential work-around.

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I had the side scuppers on my 1900v and had same problem and it was my only real issue with the boat so I thought LONG and HARD about possible fixes.  Honestly I think your over thinking it, especially adding more fittings, hoses and check valves (always problematic) but I'd love to see it work.  

My plan that was all but executed was to drill through floor into bilge and have two sets of plugs, one for through transom in your case, and one for the floor to bilge. Keep the transom ones plugged normally and have the floor ones do most of incidental water drainage from diving, etc... if the extra water draining into bilge (should be minimal since most of your water comes from the holes your trnasom ones your now plugging) is truely an issue, add an exra bilge pump without the extra fittings....

You could really use just the small livewell plugs for floor drains.  I just never found through hull "sleeves" that small

action craft used to have this same system with full size plugs, on thier flats boats.  not sure if they still do.

 

Key would be to never let them be all out at same time for obvious reasons.

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I would make a separate discharge from the main bilge pump. Water can back flow though the pump, I can get water in the bilge if I submerge the bilge pump outlet. Also I would do away with the drain shutoffs, and put in deck thru hulls that can be plugged from the top. I think if used a large diameter hose from the drains, it would act as a sump hold more water and require the pump to run less often. But keep in mind this extra pump is gonna be a drain on the battery if it runs frequently. 

 

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I had my dealer tap into the up-stream side of the one-way inline scupper valve.  A line from that fitting runs to a washdown pump mounted in my aft starboard compartment.  The outflow runs through it's own outlet in the the transom above the water line.  The pump is switched independently on my console. If it looks like I'm collecting water, I flip the switch.  The water lines aren't big,  I'm guessing 1/2" I.D., so it's not an "instant" result, but it does get rid of the cockpit water in a reasonable time.  There is a filter similar to the livewell filters to keep most of the crap out of the pump.   The dealer initially set it up similar to your "two scupper" design with shutoff valves.  I found that too cumbersome and just use the starboard drain.  I step to the starboard side,the water follows me and is pumped down through the deck drain.   It doesn't solve all the issues, but it does keep my feet drier !

 

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I suggest you install a Rule 2000, with float switch, in the bilge with a separate hose and outlet.  It will easily handle your needs.

Construct your floor drains so they can be plugged.

i owned a 21' Boston Whaler center console with no scuppers for over twenty years and never had wet feet.  A Rule 2000 took care of all the rain and spray issues.

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Thanks guys.  This is all great information and insight.

4 hours ago, justfish said:

My plan that was all but executed was to drill through floor into bilge and have two sets of plugs, one for through transom in your case, and one for the floor to bilge. Keep the transom ones plugged normally and have the floor ones do most of incidental water drainage from diving, etc... if the extra water draining into bilge (should be minimal since most of your water comes from the holes your trnasom ones your now plugging) is truely an issue, add an exra bilge pump without the extra fittings....

I am definitely over thinking it.  Your idea is obviously way simpler and would basically accomplish the same thing.  I was hoping to find the best of both worlds in a deck drain that had both a strainer grate but could also be plugged from the top.  The ball valve idea was just for redundancy if the system failed and I wanted to make sure no water got into the bilge.

I've actually been using rabuds and plugging the stern drains for a while and it works very well.  This idea was more for convenience for situations when I have the stern plugs in and am in one spot throwing the cast net alot or dumping buckets of water to clean off the deck.  My boat is also a little squatty and has a notched transom, so there is some use to being able to pump water out of the cockpit without letting it get into the bilge like in the case of a stern wave or boat wake.  My livewell had also delaminated from the console and so water would spill out of the resulting gap and drain into my cockpit through the console.  I have since had this fix and there shouldnt be anymore gaps for water to spill out. 

I'm going to think more about your idea and may end up going that route.

1 hour ago, Grant said:

I had my dealer tap into the up-stream side of the one-way inline scupper valve.  A line from that fitting runs to a washdown pump mounted in my aft starboard compartment.  The outflow runs through it's own outlet in the the transom above the water line.  The pump is switched independently on my console. If it looks like I'm collecting water, I flip the switch.  The water lines aren't big,  I'm guessing 1/2" I.D., so it's not an "instant" result, but it does get rid of the cockpit water in a reasonable time.  There is a filter similar to the livewell filters to keep most of the crap out of the pump.   The dealer initially set it up similar to your "two scupper" design with shutoff valves.  I found that too cumbersome and just use the starboard drain.  I step to the starboard side,the water follows me and is pumped down through the deck drain.   It doesn't solve all the issues, but it does keep my feet drier !

 

This is pretty much what I was envisioning except for the fact that your cockpit already drains through the deck but then discharges through either your under deck stern drain or the washdown pump system.  Glad to find someone doing something similar.  Would love to see any photos of your setup if possible.

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It will be a day or two before I can get pics.  Things are nuts at work right now, but I will get some for you.

In the meantime, here is a "stick figure" representation of the layout which might make it simpler to decide if it might work for you..  

 I asked the dealer to install option #2, but "surprise !, I ended up with #1. Fortunately  it has been working well for 12 years (in 3 months).

cockpit pumpout.jpg

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Way too much overthinking here. If you want to rely on an automatic pump to do the work the outfall MUST be above the waterline and the sealed tank would probably need a macerator style pump with easy access to open and clean it out. Then you will need to close the drain lines on the transom. NO connecting them as water will always seek its level unless you have a good check valve and you are back to square one.(Poor check valves.)

The biggest problem with our check valves is that the difference between the deck and outside water level is too small to create much back pressure to seal a valve and they are difficult to get to to clean them (just a little trash will stop the seal) External systems like ray buds are the best bet because of easy access to clean and maintain.

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