Sunday, November 4, 2018

Getting Rid of the Rain Water

Keel Stepped Mast = Occasional Rain Water in the Bilge

In a recent edition of the Mainsheet Magazine for Catalina Owners, Seth Martin had written a great article about building and installing a Bilge pump system to cope with those small amounts of water that end up in the bilge, basically what would be left over if the Automatic Bilge Pump ran, perhaps a Gallon or two over a number of rainy days.

Currently, we manually hand pump out the rain water and then soak up what the pump cannot get with a few diapers and finally dry the bilge with a few paper towels. I did purchase a battery operated fluid transfer pump from Amazon, but when it arrived it was marked up as an Olive Oil Transfer pump. It might work for Olive oil, but it sucks (pun intended) at pumping water!

Just to show what we're talking about.

Here's a pic of the #3 Bilge area (#1 is in front of the mast,#2 is immediately behind the mast and has the Bilge Float Switch sitting in the bottom, and this one is #3 which has the Bilge pump attached to the bottom

The water is after a few days of rain. We pumped this out by hand and then dried it up with a couple of diapers (our Grand Daughter no longer needs them 😀

It's about 3/4" and there's a similar depth in each of the other bilge areas.

There are commercial products on the market, but when I have the chance of another DIY project, that causes me to get excited. Seth's system is brilliant.

Basically the System consists of a small water pump, a digital timer to control it, some tubing and pickups all fed to a manifold connected to the Pump inlet, the Pump outlet fed to an overboard drain.

Eximius has 4 Bilge areas each connected by limber holes or tubes, so each needs a pump out.

So, first thing was to investigate the pumps available. I elected to purchase this SeaFlo Type 21 12v Diaphragm Pump on Amazon.

It arrived early :)

A quick connection to a 12v power supply to check that it ran and all is great.

It has an Automatic Pressure sensing switch but i it can be bypassed.


Then I spent a while picking out a timer. I found this 12v Digital Timer with on/off control.

Found this one, again on Amazon.

  • Rated Voltage: 12V DC; Contact Capacity: 16A
  • Full Time Range: 1Min-168 Hours; Programmable: 17 times/week or day
  • Internal battery: 1.2V/40mA (rechargeable batteries)
  • Power failure memory: 60 days; Operate Temperature: -10 to +40 C
  • Dimensions: 60x60x32mm; Net weight: 80g


Next, I needed to find a way to hold the Drainage Pickups that have to be installed in each of the Bilge Spaces. I could not find anything ready made, but was able to make them using an Electrical Installation Box from ACE hardware,

I figured I could cut them to create brackets that would hold the pickups in place but also allow for future sponge replacements.

A few minutes with a Back Saw and then clean up the edges with a Stanley knife and they are ready to go

The slot in the lower edge will allow me to push the Pickup tube in place with the Sponge below the bracket.

$0.79 x 2

In the pic, There are 4 Red & Black left over drip assemblies from a Harbor Freight Garden Drip System, I knew they would come in handy one day. All I had to do to make them suitable to act as Pickups was to cut off the barb on the Red End.

The Sponge pieces are about 1 1/4" Square with a hole pushed through with a Screw Driver.

The Black Plastic 3/16" Tees are also left over from the Drip system.

On the Left is a completed pickup, that will connect to the Pump input manifold (that will be made from Tubing)

This shows a Completed Drain Pickup with the Tube in the Bracket Slot ready to connect to the Pump Input Manifold.

Plan is to Glue the Bracket to the side of the bilge with just enough room beneath it to be able to slide the Tube & Sponge out so that I can replace the Sponges in the future.

I'll probably use 3M 4000 to secure the bracket in place.

So far so good.

Here's what the Pickup looks like from underneath.

I did a test using two of the pickups connected to the Pump via a 30' long piece of 3/16" tubing. They were placed in a small tub (Butter Spread Tub) with about 2" of water in it.

Then I ran the pump connected to my 12v power supply. It drained the Tub in less than a minute, and the Tub was basically dry, certainly dry enough to evaporate naturally.

Seth's project seems to be very suitable. He installed his in a Catalina 25, The bilge areas on our Catalina 34 already have quite a bit of equipment in them: Bilge Pump Control Float, Bilge Pump, Bilge Pump Hoses, 2nd Bilge Pump Hose, and finally Keel Bolts.

So my pickups are quite a bit smaller than those that Seth made for his boat.

The Boat's Main Bilge Pump has 1.5" tubing running from the Pump to the Overboard Discharge at the rear of the boat, that's about 25' of hose! When the pump stops because the water level is too low, the water in the hose floods back into the bilge. New Nearly Dry Bilge System will pump that water out.

However, I'm concerned that the hose from the Pump to the new Overboard Discharge vent will also be able to flood back into the bilge when the pump turns off at the end of it's 'Pump On' period. To prevent that, I'm going to install a One Way Water Non Return Valve in the discharge tubing near to the Outlet of the Pump.

With that installed, when the pump turns off, any water in the discharge hose will simply stay there, although, if the pump runs when the bilge is empty, then it will blow any water that is in the discharge hose out of the overboard discharge vent.

After several experiments, I came up with this solution.

The Pickups will be larger than originally prepared as per the pics above. The Pump will be attached to a Starboard Plate with 4 Stainless Steel Thumb screws (ACE Hardware) and the suction side will be from the middle of the two forward and the two aft pickups.

The Output of the pump will be attached to a new Vent that will be installed below the existing Aft Fresh Water Tank Vent that exits into the Cockpit beneath the Auto Pilot Control head. I'll add a non-return valve just upstream of the Pump output line to prevent water in the line from flowing back into the Bilge via the new Dry Bilge Pump.

The wiring of the Pump is pretty straight forward.

The Timer switch will have a 2amp fuse to the Bilge Pump Circuit before the Circuit Breaker - that way, if the timer fails and blows the fuse, it would not blow the bilge pump power supply - Bilge Pump is essential circuit

-ve from the Timer Switch Power Supply to Ground

-ve from the timer Switch to Ground.

So if the Timer or the Pump blow the fuse, the Circuit breaker that provides power to the Main Automatic Bilge Pump will remain live.

Ok, installation complete.

Final install was slightly different from the above as the blue pickup holders were not necessary. The pickups and sponges stay in place without any additional support.
The system has been running for two weeks and our bilge is DRY!

I have programmed the timer to turn the pump on for 1 minute every 2 hours during the day and 3 hours during the night. So far it's working perfectly, the bilge is totally dry. Time to clean the bilge and make it look pretty.

Of course, this is November, dry season here in South Florida, but we tend to have rain every couple of weeks, it rained yesterday and again today. I'll keep a watch on the bilge pump counter and on the state of the bilge itself. 

So far, I'm really pleased with the way it's working. Having a totally dry bilge is a big deal! 

See you on the water.

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