Retired from newspapers and television, currently sailing Thelonious II, a 1984 Ericson 381.
What are bilge pumps for?
I admit that for the first half of my life I figured they were there to keep the boat from sinking. But of course, they won't. Not even the manual Whale diaphragm that came with the boat will do that. Surely not the buzzy little gizmo under the floorboards that spits out of the transom.
A Rule 1500 centrifugal bilge pump is rated at 1500 gallons an hour, or 750 2-gallon buckets. Sounds powerful. It would take a strong crew to match that, not to mention 750 buckets. But in the real world, well, 1500 gallons an hour is not likely. We need only look at the stream of water our bilge pumps put out to consider that that is the amount they can handle coming in. A big manual pump does better, but it's work. Fill the bilge with hose water and try it--we should do that periodically anyhow, with a bit of citrus cleaner. Twenty strokes awkwardly bent over and I'm ready for a rest. Video here.
So why do we feel such a sense of security with our little bilge pumps? I guess it lets us sleep at night in our beds far away: Seacocks closed, hatches locked, bilge pumps on standby, nighty-night. Sure, our pumps are adequate protection against a stuffing-box drip or a heavy rain with the hatches open. Which is fine, because our fiberglass boats don't leak below the waterline anyhow. A hull breach is another class of event entirely.
So if bilge pumps have a simple job, let's try to get them to do it, which they so often don't.
--Empty the bilge. Too much to ask?
--Function when needed . Too much to ask?
--Not wear out every 18 months. Too much to ask?
Yes, probably. In any case, here are the changes I made to the new boat, and the reasons why:
Diaphragm not Centrifugal Pump
The electric submersible bilge pumps I have had, and which the new boat had too, are not self-priming.
Old system
They need bilge water to work, and if an air lock develops they won't. They are famous for whining happily and making tiny bubbles while moving no water at all, which can be surprisingly difficult to tell if the bilge happens to be slopping around. But who wants standing water in his boat? So a one-way valve is often inserted in the line. This keeps the water in the hose from running back into the bilge. If it works, of course, the pump loses its prime. Informed opinion states (I'm citing Maine Sail, among others) that a one-way valve in a bilge line is a terrible idea.
I believe it. It was a one-way valve that caused me unnecessary worry offshore (Why is the pump running but the water not going down. Am I sinking?). The current boat came with two such check valves, one for the main bilge and one for the shower bilge. The main bilge valve worked too well--the pump wouldn't run unless the bilge got half full. The shower bilge valve was clogged closed with human hair, permitted no bilge water at all to pass, and had been that way for years.
However, cutting out the one-way valves presents a problem. Many bilge hoses have no anti-siphon loop, and no vent either. Apparently not required, and not tradition. So a one-way valve keeps the bilge pump from siphoning water in on some points of sail.
I tried to add an anti-siphon loop and vent to my bilge hoses. No room back there on this boat. Forgetaboutit. So, how to resolve these conflicts?
Early 1980s E38s, and other models, came from the factory with diaphragm bilge pumps located in the engine compartment. Mine were removed long ago and replaced with centrifugal submersibles wired to automatic float switches. None of that fit very well between the keel bolts. Perhaps the change was made because centrifugal pumps do move more water than an equivalent diaphragm pump. But then you need a check valve.
Diaphragm pumps don't need in-line one-way valves, because the pump itself contains two. There is no run-back. There is no siphon possibility. They move less water, but they can suck it all out because the pump is not submerged, doesn't require a prime to operate, and can run dry without harm to itself.
I chose the Jabsco 3720 Light Duty diaphragm pump with a suction lift of 7 feet and 3/4-inch ports. After some head-scratching, I mounted it in a seat locker, rather than the engine compartment. Diaphragm pumps are sensitive to particles, so a separate pre-strainer is required.
New system
To provide automatic operation, I ordered the familiar Rule Three-way panel switch. I like it mounted here, under the protection of the saloon table, because if I happen to be manually activating a bilge pump, I am also likely looking at the bilge water.
Instead of a traditional float switch, I went with a newfangled electronic sensor, the Water Witch #101. The Water Witch fits more easily in our bolt-challenged TAFG bilge.
I left the shower sump rigged with its tiny Rule pump, ancient two-pronged water sensor and factory-installed three-way switch. I installed a new one-way valve, and shrugged. We won't be using the shower much, and nothing else drains into that bilge.
The new system seems to work fine. The diaphragm pump hose gets all but a quarter inch of water out. Kind of a joke, though, since depending on trim the lowest bilge can be any of three compartments. The old pumps were, as is typical, a maze of hacked wires, tape and cable ties, and the hoses were stained and tired. The new installation looks neat and clean, with all bilges painted Brightside white. The diaphragm installation is hidden under a seat locker insert that protects the wire runs there and expands the usable space.
This was a theoretically easy Saturday-morning job that wound up taking two weeks, three orders of gear from Defender, and upwards of $300 including a low pass by an actual boat electrician.
None of it will stop us from sinking. But it does mean a good night's sleep.
Added: Modification to drain remote compartments:
I removed the strum box and added five feet to the lightweight bilge pickup hose, incorporating yet another in-line debris filter, this one easy to see and clean out if necessary.
Now the hose will reach all the way to the mast, to suck out water under there, or in any compartment.
The lengthened hose normally rests coiled in the main bilge, weighted at the end.
Manually suctioning sections with this extended hose gets out most water, so that now only a few paper towels are required for the absolute dryness my psychiatrist said would make me feel better and possibly stave off expensive hospitalization.
We all know that some water in the bilge is normal. I don't know why it drives us nuts.
I admit that for the first half of my life I figured they were there to keep the boat from sinking. But of course, they won't. Not even the manual Whale diaphragm that came with the boat will do that. Surely not the buzzy little gizmo under the floorboards that spits out of the transom.
A Rule 1500 centrifugal bilge pump is rated at 1500 gallons an hour, or 750 2-gallon buckets. Sounds powerful. It would take a strong crew to match that, not to mention 750 buckets. But in the real world, well, 1500 gallons an hour is not likely. We need only look at the stream of water our bilge pumps put out to consider that that is the amount they can handle coming in. A big manual pump does better, but it's work. Fill the bilge with hose water and try it--we should do that periodically anyhow, with a bit of citrus cleaner. Twenty strokes awkwardly bent over and I'm ready for a rest. Video here.
So why do we feel such a sense of security with our little bilge pumps? I guess it lets us sleep at night in our beds far away: Seacocks closed, hatches locked, bilge pumps on standby, nighty-night. Sure, our pumps are adequate protection against a stuffing-box drip or a heavy rain with the hatches open. Which is fine, because our fiberglass boats don't leak below the waterline anyhow. A hull breach is another class of event entirely.
So if bilge pumps have a simple job, let's try to get them to do it, which they so often don't.
--Empty the bilge. Too much to ask?
--Function when needed . Too much to ask?
--Not wear out every 18 months. Too much to ask?
Yes, probably. In any case, here are the changes I made to the new boat, and the reasons why:
Diaphragm not Centrifugal Pump
The electric submersible bilge pumps I have had, and which the new boat had too, are not self-priming.
Old system
They need bilge water to work, and if an air lock develops they won't. They are famous for whining happily and making tiny bubbles while moving no water at all, which can be surprisingly difficult to tell if the bilge happens to be slopping around. But who wants standing water in his boat? So a one-way valve is often inserted in the line. This keeps the water in the hose from running back into the bilge. If it works, of course, the pump loses its prime. Informed opinion states (I'm citing Maine Sail, among others) that a one-way valve in a bilge line is a terrible idea.
I believe it. It was a one-way valve that caused me unnecessary worry offshore (Why is the pump running but the water not going down. Am I sinking?). The current boat came with two such check valves, one for the main bilge and one for the shower bilge. The main bilge valve worked too well--the pump wouldn't run unless the bilge got half full. The shower bilge valve was clogged closed with human hair, permitted no bilge water at all to pass, and had been that way for years.
However, cutting out the one-way valves presents a problem. Many bilge hoses have no anti-siphon loop, and no vent either. Apparently not required, and not tradition. So a one-way valve keeps the bilge pump from siphoning water in on some points of sail.
I tried to add an anti-siphon loop and vent to my bilge hoses. No room back there on this boat. Forgetaboutit. So, how to resolve these conflicts?
Early 1980s E38s, and other models, came from the factory with diaphragm bilge pumps located in the engine compartment. Mine were removed long ago and replaced with centrifugal submersibles wired to automatic float switches. None of that fit very well between the keel bolts. Perhaps the change was made because centrifugal pumps do move more water than an equivalent diaphragm pump. But then you need a check valve.
Diaphragm pumps don't need in-line one-way valves, because the pump itself contains two. There is no run-back. There is no siphon possibility. They move less water, but they can suck it all out because the pump is not submerged, doesn't require a prime to operate, and can run dry without harm to itself.
I chose the Jabsco 3720 Light Duty diaphragm pump with a suction lift of 7 feet and 3/4-inch ports. After some head-scratching, I mounted it in a seat locker, rather than the engine compartment. Diaphragm pumps are sensitive to particles, so a separate pre-strainer is required.
New system
To provide automatic operation, I ordered the familiar Rule Three-way panel switch. I like it mounted here, under the protection of the saloon table, because if I happen to be manually activating a bilge pump, I am also likely looking at the bilge water.
Instead of a traditional float switch, I went with a newfangled electronic sensor, the Water Witch #101. The Water Witch fits more easily in our bolt-challenged TAFG bilge.
I left the shower sump rigged with its tiny Rule pump, ancient two-pronged water sensor and factory-installed three-way switch. I installed a new one-way valve, and shrugged. We won't be using the shower much, and nothing else drains into that bilge.
The new system seems to work fine. The diaphragm pump hose gets all but a quarter inch of water out. Kind of a joke, though, since depending on trim the lowest bilge can be any of three compartments. The old pumps were, as is typical, a maze of hacked wires, tape and cable ties, and the hoses were stained and tired. The new installation looks neat and clean, with all bilges painted Brightside white. The diaphragm installation is hidden under a seat locker insert that protects the wire runs there and expands the usable space.
This was a theoretically easy Saturday-morning job that wound up taking two weeks, three orders of gear from Defender, and upwards of $300 including a low pass by an actual boat electrician.
None of it will stop us from sinking. But it does mean a good night's sleep.
Added: Modification to drain remote compartments:
I removed the strum box and added five feet to the lightweight bilge pickup hose, incorporating yet another in-line debris filter, this one easy to see and clean out if necessary.
Now the hose will reach all the way to the mast, to suck out water under there, or in any compartment.
The lengthened hose normally rests coiled in the main bilge, weighted at the end.
Manually suctioning sections with this extended hose gets out most water, so that now only a few paper towels are required for the absolute dryness my psychiatrist said would make me feel better and possibly stave off expensive hospitalization.
We all know that some water in the bilge is normal. I don't know why it drives us nuts.
