|
The Bilge Mess
|
||
|
In the first picture you can see the mess. I poisoned the crap growing in the bilges last weekend with a dose of chlorine bleach. That would be the brown (formerly green) stuff you see all over the bottom, which once fouled my bilge pump float switch. I highlighted the non-watertight crimp connections going to the bilge pump. These need to be soldered and water tight to prevent a short circuit and subsequent pump failure.
Here in the second picture, I've cleaned and dried the bilge.
These are the parts I'm installing, the first is a PVC drain grate; the second, a two tier switch mount constructed out of PVC wood replacement stuff that was left over from last year's teak replacement project. When this project is complete there will be two bilge pumps and two float switches wired to two independent battery banks. If one fails the other should take over, if one can't keep up with the flooding, the second should help out as soon as the water rises an additional 3/4 of an inch, and activates the second float switch. When all is said and done, I should be able to move somewhere around 3,000 gallons per hour from inside the boat to the outside for as long as the batteries last. After that I had better pray the Coast Guard shows up or my muscles hold out when I'm forced to work the manual pump.
The PVC drain grate I installed upside down with a stainless screw and washer to the bottom of the bilge. It will be a holder for my bilge cleaner. I'm going to see if a Clorox toilet sanitizer tablet will be as effective for 2-3 months of bilge sanitizing as it is for the crapper at the house. If all goes well; no more stuck bilge pump switches with a minimum of attention from me. God, I love redundant systems; one less thing to worry about.
The original pump has been relocated to make room for the mounting of the second pump. The second switch has also been installed.
Below are the check valves assembled and ready to install. I've been doing some research and chatted with some folks on line about check valves. There are many of the opinion that check valves shouldn't be installed on bilge pumps, for fear that they will jam/clog and prevent the flow of water out of the hull. I decided to go with check valves because: the chlorine tablet will prevent stuff from growing in the bilge, the redundant pumps & switches allows for one or the other to fail without losing the capacity to pump water over the side, the pumps have their own strainers to prevent crap from being sucked up, and there are no metal parts in the valves to corrode. In my opinion, this pretty well mitigates the risk. Of course, I'll be monitoring it just to make sure. By the way, the U.S. Navy uses check valves on their eductors and bilge pumps located below the waterline even if the discharge is above the waterline. Yeah, they're a lot bigger, but the principle is the same, keep as much water as possible on the outside of the boat. I've also had 20 years of personal experience with their use in salt water supplied fire fighting systems for munitions magazines. I'll be sleeping fine at night with these valves installed. Running them both to one line will mean I don't have to install a new through hull fitting and hose for the second pump. 3/13/07: I got an e-mail from some joker that says you can't hook up two pumps to a single hose meant for one pump. I beg to differ, because as you can see... I have. Quick lesson in hydraulics to follow: I've got 20 years experience working with hydraulics systems from 100 to 3000 psi on missile launchers for the U.S. Navy. I'm no engineer but I know a couple of things. The bilge pump line is open to atmosphere, it's not a closed loop system, so the fluid will simply increase it's velocity through the line if both pumps are running. V=.3208Q/A or Velocity = 0.3208 x Flow Rate through I.D. (GPM) divided by internal area (Square Inches) In other words there shouldn't be a problem with capacity in the line, it should just shoot twice as far out the back of the boat when both pumps are running. Which, I might add, is not the normal mode of operation. If both pumps are running at the same time something has gone very wrong. In the next photo you can see the new bilge switch mounted to the left of the original. I managed to get the exact same model as was installed; bet if I had tried to do that, it would've been impossible. They're three position switches for automatic & manual operation, and off.
Plumbed up, wired and working as advertised.
Both pumps pushing water out of the hull. I'll be damned. It shoots out just about twice as far as it used to . I guess that formula still works.
Update: It's been two months. My boat smells good and nothing is growing in the bilges. On top of that there's still better than half a tablet of chlorine still in the holder. I may only have to drop two a year in there.
|
|
