Water in the bilge

[Scott Harris]

I'm trying to understand how boats work. I have a few questions.

1. What are the different ways that water gets into the bilge?

2. How much water is too much?

Thanks for the help.

 

[rsn48]

#1.
1) through the stations
2) through windows and port holes
3) through deck areas that were never sealed properly (older boats)
4) through the anchor locker (older boats)
5) where ever "stuff" is joined together but begin to separate
6) where ever there are holes that have something in them, sea cocks, thru hulls, bolts through the transom

How much is too much?
The answer will vary with boat types and designs and how your bilge pumps are set up and whether they are working.

 

[South of Heaven]

First determine if it's salt water or not.

 

[twistedtree]

When the waters gets to your neck, it's time to swim for it.... But more seriously, if your pump is cycling on a regular basis, it should be looked into.



I'd break it down into two different categories. Water that gets into the bilge by design, and water that is collecting there due to leaks.


By design, I think the most common is a shaft packing gland. They are intended to drip. Other sources could be condensate from HVAC systems, and even gray water from showers and sinks. It all depends on how your boat was set up. Gray water should really go directly overboard if possible, or into an enclosed sump and pumped overboard. In the bilge, it will stink things up. If you have a packing glad for a shaft seal, then the bilge will be wet, and adding a bit of condensate isn't a big deal. But if you have a dripless shaft seal, then I'd want to condensate collected like the gray water, and I'd be looking for a completely dry bilge. This is my personal preference - completely dry. If nothing else, it makes it clear when you have a leak.


As for leaks, RSN48 provided a good list of candidates.

 

[obthomas]

MY Taiwanese Labelle has a hollow keel. Center of the boat in the engine room is like a floor drain into this hollow keel. Any water from shaft packing, air conditioners, abnormal leaks goes into the keel. The keel also has an automatic bilge pump. With this arrangement my boat stays very dry. I have had trouble with level switches for this bilge pump so recently I put it on an automatic timer set to run 5 minutes ever day.

 

[oscar]

On my boat any is too much.

 

[sunchaser]

On my boat any is too much.

 

[moparharn]

The silent killer.

If the water is coming from above you had better find the origin as you will likely have moisture damage at the origin to the bilge that will occur over time.

A/C and packing glands may be a more common source, but that does not mean they cannot create a problem for you.

As mentioned in a prior post (keel sump area) a sump or containment area lets the water drain to a place that is impervious to water and pumped overboard regularly. As long as you understand where the water is coming from and that the cause is not a problem (loose/deteriorating packing gland, leaking deck joints, through hull problem, etc) then you should isolate it and make sure it goes overboard. One issue with overboard is the possibility of oil or fuel contamination. Make sure what you pump overboard is environmentally responsible.

For me, the single biggest reason for rejecting a survey is moisture intrusion/damage. Stringers, decks, tanks, transoms, and more can all be compromised by moisture. Not dealing with it is the silent killer.

There are many good posts on this forum about moisture management. I just was part of another dealing with limber holes. Improper placement and sealing of limber holes has killed many a stringer. Wet stringers have killed many a boat sale or price.

 

[Tator]

Some of this will depend on your cruising area. I find in rainy SE Alaska there will be condensation from the hull sweating below the waterline and running into the bilge. Other than having an insulated (or wood) hull, I know of no way to avoid it. I don't think a perfectly dry bilge is possible in this situation.

Tator