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Has anyone here ever built one of these? (Bilge drying system)


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Thanks for that, looks like a clever and affordable solution to the problem.

I'm going to try it.

Back in a while.

I have timers but the rest of it, I have to get.

Cheers

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Not done it, but plenty of people on the power boat forums have. There are commercially available systems for more money than the DYI, using about the same components. Supposed to work well. My sailboat has a dry bilge without needing this, but I've thought about doing it on the power boat which always seems to get a little  puddle in the middle bilge. 

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Thanks for the replies. I think I’ll have a go at it, but I’m torn between using a simple timer and have the pump run for a few minutes every day -or- building more complicated circuitry that makes the pump come on periodically and stays on only if the pump is pumping water. 
 

In one of the articles I read, I guy took one of those Rule pumps that comes on every 2-1/2 minutes and disassembled it just to get the circuitry that turns the pump on and off. 

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28 minutes ago, Quickstep192 said:

Thanks for the replies. I think I’ll have a go at it, but I’m torn between using a simple timer and have the pump run for a few minutes every day -or- building more complicated circuitry that makes the pump come on periodically and stays on only if the pump is pumping water. 
 

In one of the articles I read, I guy took one of those Rule pumps that comes on every 2-1/2 minutes and disassembled it just to get the circuitry that turns the pump on and off. 

That's about all those timer-based Rules are good for. I've never had one last more than a year.

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A diaphragm pump is checked and preferable for something like this.  You don't want the the water in the line working it's way back down. A simple timer relay and float will work fine. You want the time delay latched when the float cycles back off to give the extra drying cycle. You can get a pretty basic timer to setup this way.

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What people are using are the cheap lobe type pumps, about $30 on Amazon. Really no need for it to come on more than every couple of hours unless your boat is a sieve. 

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Putting in a dedicated system to run on a timed auto cycle like this makes no sense to me. Even if it's super cheap.  You could do the same thing for very little cost with a proper primary or secondary bilge pump and only have it run when it needs to. The drying function is basic relay logic.  Having something run on a cycle that may or may not be doing anything seems a bit odd.

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2 hours ago, SASSAFRASS said:

Putting in a dedicated system to run on a timed auto cycle like this makes no sense to me. Even if it's super cheap.  You could do the same thing for very little cost with a proper primary or secondary bilge pump and only have it run when it needs to. The drying function is basic relay logic.  Having something run on a cycle that may or may not be doing anything seems a bit odd.

When you say you could do the same thing for very little cost with a proper primary or secondary bilge pump and only have it run when it needs to, are you suggesting using regular bilge pumps? I don't think a regular bilge pump can get that last 1/2".

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A standard centrifugal pump in a well will work, without a well a diaphragm pump like whale can be setup to for low suction.   The residual water is due to the combination of the pump loosing suction and the mechanics of the float switch.  With a low suction and time delay run cycle after the float switch has deactivated you will be dry in a normal duty cycle.

A low suction is going to be prone to fouling so the prudent thing would be to have a high volume centrifugal primary and use a diaphragm as the secondary. Both setup for automatic operation. On a small boat or one that is not used much, IE no bilge hairballs the diaphragm only is probably fine.

 

You could do the setup you linked and it will probably be fine, but seems like the same amount of work as setting up the above and it won't be a usable bilge pump.

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Isn't part of the problem the loop that keeps the high point above the waterline and the size of the hose.  Quite a bit of water can run back down the hose and into the bilge depending on the length of the run.  The small diameter hose means that very little water will return.

 

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On 8/30/2021 at 3:41 PM, gkny said:

Isn't part of the problem the loop that keeps the high point above the waterline and the size of the hose.  Quite a bit of water can run back down the hose and into the bilge depending on the length of the run.  The small diameter hose means that very little water will return.

 

Just drain your bilge drier setup  into the galley sink 

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On 8/30/2021 at 7:10 AM, SASSAFRASS said:

A standard centrifugal pump in a well will work, without a well a diaphragm pump like whale can be setup to for low suction.   The residual water is due to the combination of the pump loosing suction and the mechanics of the float switch.  With a low suction and time delay run cycle after the float switch has deactivated you will be dry in a normal duty cycle.

A low suction is going to be prone to fouling so the prudent thing would be to have a high volume centrifugal primary and use a diaphragm as the secondary. Both setup for automatic operation. On a small boat or one that is not used much, IE no bilge hairballs the diaphragm only is probably fine.

 

You could do the setup you linked and it will probably be fine, but seems like the same amount of work as setting up the above and it won't be a usable bilge pump.

I have yet to get a centrifugal to get that last 1/2" they always lose prime first. I use a small primary and a large secondary. My boat is a very flat bottom boat with multiple "bilges" that hold water. Living in Houston TX there are times when the boat will sweat enough to fill all those bilges. Because of the flat bottom there is no way to create a well, so the 1/2" of water is spread over  large area. I am going to try the idea and make it automatic only when plugged into 110 volt.

JJ

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1 gal 12 volt corded vac + good sponge + bucket + small dehumidifer = dry bilge on a mooring for less time and effort then trying to build a "bilge drier system.

First 3 components allow you to keep bilge dry when healed over sailing, especially in flat/shallow bilged boats where the water can't get to a small sump...

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On 9/6/2021 at 9:31 AM, johnsonjay17 said:

I have yet to get a centrifugal to get that last 1/2" they always lose prime first. I use a small primary and a large secondary. My boat is a very flat bottom boat with multiple "bilges" that hold water. Living in Houston TX there are times when the boat will sweat enough to fill all those bilges. Because of the flat bottom there is no way to create a well, so the 1/2" of water is spread over  large area. I am going to try the idea and make it automatic only when plugged into 110 volt.

JJ

You need a well and a checked pump for the centrifugal setup.  The whale low suction or similar diaphragm do pretty good without, they are all checked as well.  The setup in op will certainly work. Dehumidifiers are just moving the work and water, it still needs to go somewhere. If doing the small pump I would probably steer clear of the auto cycle and use a float or sensor and delayed run cycle logic IE drying pump is starting via float or solid state sensor and running for x time after sensor is cleared. It's all personal preference, a dry bilge is great no matter what, lots of ways to get there.

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9 hours ago, SASSAFRASS said:

Dehumidifiers are just moving the work and water, it still needs to go somewhere.

True, but it’s a lot easier/simpler to plumb the dehumidifier to drain down into the sink…

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I've used a dehumidifier draining into the galley sink for several years now, and it's been a huge improvement for the interior atmosphere. But that does nothing to remove the last bit of water from the bilge. In my case the bilge is shallow and flat, with closely spaced timbers (cold molded wood construction), and no connection between the port and starboard bilges unless the water gets over 6" and tops the main keel timber. Centrifugal pumps are impossible to position at the lowest point as the space is too tight, so I end up with 2" or so of water, or about 10 gallons, when I vacuum it out. Keeping a dry bilge seems like a good idea, particularly for a wood boat.   So this idea or something like it is pretty appealing and I think I will give it a try. I'd prefer the solid state sensor idea over a simple timer. 

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14 hours ago, Crash said:

True, but it’s a lot easier/simpler to plumb the dehumidifier to drain down into the sink…

How do you run your dehumidifier on a mooring?  Do you keep an inverter going?  I've had no luck finding a decent (non peltier) 12v dehumidifier.  

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54 minutes ago, socalrider said:

How do you run your dehumidifier on a mooring?  Do you keep an inverter going?  I've had no luck finding a decent (non peltier) 12v dehumidifier.  

Ummm, I've got no good answer to that :(

I've only run them when plugged into shore power...

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6 hours ago, Quickstep192 said:

Are you guys talking about a regular house type dehumidifier?

Yep, I used the small Eva-Dry recommended by Practical Sailor on my last boat (Bene First 310) because I could never get all the moisture out from under the pan liner in the shallow/flat bilge area under the floorboards.  I had 120v outlets that were powered off shorepower, so a simple timer plugged into an outlet let me run it about 3 hours a day.  Kept the boat nice and dry...Obviously, my approach doesn't work when on a mooring or at anchor, though Eva-dry does sell a 12V cord...so solar panels to top of the battery may be enough?

https://www.practical-sailor.com/mailport-ps-advisor/product-update-february-2015

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13 hours ago, socalrider said:

How do you run your dehumidifier on a mooring?  Do you keep an inverter going?  I've had no luck finding a decent (non peltier) 12v dehumidifier.  

Anybody know how much current the Peltier units pull? Sure, Peltier sux for energy efficiency but wins in terms of cost and simplicity. 

If there is need for more dehumidification than the Peltier units offer, an inverter running off properly programmed load terminals on a solar controller would be the way to do it on a mooring. Same for the Peltier, but skip the inverter.

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4 hours ago, Crash said:

Yep, I used the small Eva-Dry recommended by Practical Sailor on my last boat (Bene First 310) because I could never get all the moisture out from under the pan liner in the shallow/flat bilge area under the floorboards.  I had 120v outlets that were powered off shorepower, so a simple timer plugged into an outlet let me run it about 3 hours a day.  Kept the boat nice and dry...Obviously, my approach doesn't work when on a mooring or at anchor, though Eva-dry does sell a 12V cord...so solar panels to top of the battery may be enough?

https://www.practical-sailor.com/mailport-ps-advisor/product-update-february-2015

Ahh got it.  Your original post mentioned a mooring, hence the question.  I'll take a look at the 12V option for the Eva-dry!

I strongly suspect a small compressor-based dehumidifier powered by an inverter with proper controls would be more efficient and effective than a Peltier device.  

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  • 2 weeks later...

I put a similar system to the original post in my Cav 28, which has no bilge to speak of.

Total cost less than A$100, about US$ 70, including the timer, which I have set to run 2 minutes in 24 hours.

Initially, I had the 3mm hoses connected to the top of the electrical switch-plates, as shown in the initial post but it wasn't picking up the last dregs, so I now have the hose horizontal, flush against the hull, with the sponge clamping it down.  It gets as much as I could expect, leaving just a smear of water, about the same as a manual sponge-out.

The pump seems happy to run with very little water in the lines.  It pulls water out of the bigger section when the smaller section is already dry.

It drains to the galley drain below the sink and no water comes up to the sink.  Unless I leave the seacock closed.

I'll keep an eye on it and expect to have to renew the sponges, maybe annually.

Thanks for bringing it to my attention.

Cheers

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