"rotten egg smelling" bilge water

B

bambrose

Member
Joined
Jul 14, 2006
RO Number
22371
Messages
11
Have '86 Carver Mariner. Found about 2 gallons of "rotten egg smelling" bilge water under the wooden platform holding my batteries in the engine compartment (about 3 inches off floor)and a slimy, wet film on the platform itself with the platform blackened. No evidence of fire or sparks. Assume rotten egg smell is sulphur caused. All electrical working fine. Both batteries (Optima Marine AGM's) tested OK and not leaking. Trucharge charger is only 4 years old and is a 3 level trickle charger. No frayed or broken wires evident. Holding tank and piping replaced 3 years ago and not smelling or leaking. Don't know what else to check. Shower drains to pump. AC to forward bilge but water there is clear and no smell. Any clue? Is boat safe to run?
 
Sounds like some old standing river water. I would clean up the mess and see if water returns back to that area. It had to come from somewhere. Check your rudder and shaft seals.
 
I believe over charging batteries will cause them to Vent. This happened to one of the boats I owned in the past. It had water tight battery boxes and it was not uncommon to find them sitting in several Inches of water. Some of the older chargers continued to charge even if the battery was fully charged. Al may be right but I would not rule out the batteries. It is hard to fill batteries without overfilling and spilling some unless you have a bottle designed for the task.
 
" It is hard to fill batteries without overfilling and spilling"

They are AGM. No fill.
 
Alot of times that "rotten egg smell" is caused by water mixing with oil(bacteria). Is there any chance of that happening in your bilge...any leaks? That is what I would check for. If that is the case you'll want to wipe out any that you can, then scrub it with detergent. I keep oil absorbing pads under my engine to soak up any oil and change them whenever I change engine oil. Without these pads oil drips off the engine and hits the water. Oil floats on the water so as the water sloshes for and aft/side to side it coats EVERYTHING. Then the bacteria starts eating it. Once you've got it all cleaned up you can test whether this was your problem by drying the bilge. If there is no water then no bacteria to eat the oil. Hopefully this helps.
 
Agree with the oil and water theory. Had this same smell on one baot many years ago, oil mixed with water. Nasty smell.

Jonathan
 
do you know where the water is coming from??
use some bilge cleaner then dry the area.
 
if water is in the bilge under the batteries on a mariner, this bilge compartment is connected to the engine bilge area. So very liely oil contamination,.
 
So far so good. Ripped out old saturated plywood battery box platform, cleaned previously unaccesible part of bilge (under that platform) of greasy smelly water, replaced with a starboard platform and new battery boxes and 3 weeks later - no smell. Thanks for the help!
 
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