Monday, January 16, 2012

More Bilge Pump Thoughts

I spent the whole day hooking up one of the two Rule 3700 bilge pumps.

Float Sensors:  One issue was attaching the float sensor.  I tried using extra large hose clamps, and this popped the bilge pump off it's mount.  The solution was to go back to using tie-wraps.  I tested the automatic switch in a bucket of water.  I still need to test it in place to validate that it is working. 

Ring Terminal Block:  The ring terminal bock worked well.  I attached it to a stainless angle bracket used to support the anti-siphon loop in the exhaust system. 

Pig Tail Wiring and Corrosion:  While the wire splices were working, I cut these out and re-spliced them with new shrink wrap.  I found two of the wires somewhat corroded.  I cut them back a bit more--still corroded, so I brushed the wire to clean them as much as possible.

The lower pump I just installed was formerly in the upper position and suffered less corrosion than the lower one.  I ordered a new plastic mounting bracket for the upper bilge pump. I plan to cut these wires back substantially farther.  I have yet to test the float switch. 

Submersible Bilge Pumps:  Submersible pumps just don't seem to last very long.  And these fail because of the wiring gets wet.    I was tempted to buy a new Rule 3700 bilge pump.  Each of these pumps should put out about 2500 gallons per hour although the check valves might inhibit flow to a lesser flow.  So you would think there are good pumps.  They are not.  I think they are junk because they sit in the water and water gets into the wiring--every time.

The normal price for this pump is $150. Should I replace a bilge pump if I can make it work another year or two--in particular since I have a second back up pump?  I decided not to, but I'll keep an eye on both.  The new more flexible hose and the terminal block make it easy for me to remove these pumps for maintenance.

Thinking back on all the failed bilge pumps I've repaired, all of them were submersible type pumps and each had corrosion on the wire supplying them with electricity.  So it seems the best solution is to mount a non submersible bilge pump well  above the bilge as the primary bilge pump.  And of course an engine driven high volume bilge pump is still the solution for a serious leak.

In any event, I now have an easy to pull and maintain bilge pump.  The new flex hose was a smart upgrade.  The terminal block makes it possible to remove the entire assembly for test and service. 

Wiring Improvements:  I have been running my pump off the main panel. Some people prefer to run it straight from the battery as anyone who shuts off the main panel breaker would interrupt power to the bilge pumps.  I leave that breaker on all the time.  Still someone might not know that switching it off shuts off the bilge pumps.  My plan is to move the bilge wiring power connector to the plus side of the switch, or the battery, and install two bilge pump toggles to override the automatic setting to manual.  I am undecided about fusing this circuit or not.  A failed fuse would be a bad reason to sink the boat, and submersible pumps don't cause fires.  On the other hand a over sized fuse would not be likely to fail and I do have two pumps.  

Wet Bilge:  I always have 3" of water in my bilge.  It  bugs me.  Some people use wet/dry vacuums for this purpose. My bilge is too deep for that.  I'd like to add a non-submersible pump on a manual switch located in a handy spot to suck all this out.
 For the time being I have a small oil change pump with a long copper tube that I can use to suck out the last of the bilge water, and then pump it the other way into a larger container for disposal at an auto service station--just like I do for oil changes.  Later on, I'll install a more permanent system to dry out my bilge manually.

Still To Do:

1) Test the automatic switch in the bilge by pouring water down there.
2) Rewire both bilge pump controls from an un-switched 12V DC source to the terminal block. (I need two toggle switches for this)
3) Rewire the #2 bilge pump pigtail.  (Need liquid electrical sealant)
4) Install the #2 upper bilge pump with new flex hose when the new base comes in.
5) Measure the riser loop--making sure there is 18" of rise above discharge--I probably have at least 12" now.
6) Replace the flex hose on the manual bilge pump with smooth wall hose except for the last four feet in the bilge.  Check for anti-siphon loop.  (When the weather gets warmer mount this in the cockpit).