Saturday, March 10, 2012

But what about sinking?

Shortly after moving aboard Sea Gem, Krissy explained her fear of the boat sinking while we sleep.  Although, given the right combination of bad events, Sea Gem, like any other boat, could sink, I have absolutely no fear of that happening while we sleep or under any ordinary conditions. 

Why?  Because Sea Gem has a fantastic automated pump system that can keep us dry and afloat even if we do spring a serious leak. 

Any water that comes aboard Sea Gem will accumulate in the bilge, which is the lowest part of the boat.  Here is our bilge:
 


The cylindrical object in the middle is a water pump that can pump nearly 2000 gallons of water per hour from the bilge to the outside of the boat.  To its right is a float switch: when the water reaches the float switch, the bilge pump turns out automatically.  We test the pump frequently to ensure that it is functional at all times.  So the short answer for why we won't sink in the middle of the night is because we have an automatic bilge pump. 

But what if the bilge pump fails, you ask?  Or, what if the bilge pump is working but the float switch fails?

Well, the bilge pump you see is actually our backup automatic bilge pump.   If you look very closely, behind the bilge pump is the top of another bilge pump, which can also pump nearly 2000 gallons per hour.  The partially hidden pump is actually our primary bilge pump.  It is lower down in the bilge, so it is the first to turn on.  If water comes in extremely quickly and overwhelms the primary pump, or if the primary pump is not working, then the secondary pump will kick in to keep things under control. 

For even more redundancy, our primary bilge pump has two float switches.  If the first float switch does not work, then the pump will turn on when the water reaches the second float switch.  And, of course, if somehow both float switches fail, there is always the backup bilge pump with its own float switch...

But what if, somehow, all three float switches fail, you ask?  What then?

Well, as highly improbable as that situation is, we are prepared for it.  Next to the primary bilge pump is a fourth float switch that is hooked up to a piercing alarm in the cabin.  If the water reaches the level of the secondary bilge pump (i.e., the primary pump is overwhelmed or is not working), the alarm comes on and is more than loud enough to wake us, Moishe, and anyone in a nearby boat from the deepest sleep.  The alarm is powered by its own batteries, so even if our entire electrical system dies, the high-water alarm will still
sound. 

Once awake, we can keep the boat dry until we can find and stop the leak using any number of methods.  If our electrical system and the pumps are working, we can flip a switch to override the bad float switches and manually turn the pumps on.  If the pumps aren't operable for some reason, we have a manual bilge pump (manual as in you manually pump a handle) that one of us can use while the other finds and plugs the leak.  As you can see in the first photo, almost all of the places where a hose or fitting could fail and allow water to enter the boat are located in the same place by the bilge, so it would be easy to locate and turn all the valves to the off position, and we have a variety of wooden plugs (conveniently located next to the fittings) that we could pound into a failed hose or fitting if the valves won't turn. 

Convinced we are covered?  Or are you wondering what we do if all of our float switches and electric pumps fail and our manual pump fails too?  

We have a backup manual pump too, of course.  And if too much water is coming in to manually pump (or if, somehow, both manual pumps are broken), we have two of the most powerful backup pumps around: our two diesel engines.  We can turn a valve that causes the engines to pump water from the bilge (they normally pump water from the ocean for cooling). 

So, can Sea Gem sink?  Of course, but it sure is unlikely, and it certainly isn't going to happen while we sleep.

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