Fuel Smell

[cal 39 guy]

I am getting a strange petroleum smell in cabin. I don't see any leaks around engine and seems to be coming from bilge and diesel tank area. although i don't see a sheen in bilge water. But when i use the shower it smells worse. and when i pump out bilge, it smells less.
the diesel tank seems entombed in a wood frame making up the port couch.
Any advice on how to cut into tank area to inspect.
And tank has maybe 50 gals fuel in it.
Thanks!

[shorebird]

What material is the tank made from? How is your access to the fittings? Can you inspect the fuel line and all connections before cutting into your tank?

[cal 39 guy]

tank looks like stainless. i do have a small round hole in wood where i can see fuel out
lines and a shut off valve. and i can see filler hoses. all hoses look ok. no sign of leakage.

[Kettlewell]

You may have a weeping fuel tank, or it might just be a leaking hose or connection on the top of the tank. After awhile hoses harden and/or hose clamps rust out, etc., and you can get small leaks at the connectors on top of the fuel tank. Sometimes, bilges just need an extra good scrubbing with degreaser to get the fuel smell out of the boat--just a tiny bit of oil down there can smell up the whole boat.

Why would it smell worse in the shower? By any chance does the vent line for the fuel tank vent near a port that serves the shower area? In other words, the fuel fumes are exiting via the vent line and coming in through the port into the head.

[cal 39 guy]

my bad/ it doesn't smell worse in shower. But when the bilge fills up with water from shower it smells much worse in bilge. then when it pumps out, it smells less. ill still go on a hunt for vent line.
thanks!

[Kettlewell]

If your shower drains into the bilge I strongly suspect you just have very stinky bilges! Seriously, that is a bad design. The soap, hair, and other crud that goes down there will mix with oil and dirty water and will create a very sulfurous smelling soup that does have a petroleum smell. You should set your boat up so the shower has its own catchment area that can be pumped over the side. And, you will need to scrub your bilges out several times, rinsing with lots of fresh water.

[cal 39 guy]

Shower does drain in bilge and it was a stink zone.
did a 3 hr bilge flush with fresh water. hopefully that will do it


i got access to one long side of fuel tank (75 gallon aluminum) and saw
no leakage. also the tank vent hose looks like automotive heater hose.
and 1/2 the upper section of tank fill hose is clear.
(maybe vinyl hose?)

[rwidman]

Originally Posted by Kettlewell

If your shower drains into the bilge I strongly suspect you just have very stinky bilges! Seriously, that is a bad design. The soap, hair, and other crud that goes down there will mix with oil and dirty water and will create a very sulfurous smelling soup that does have a petroleum smell. You should set your boat up so the shower has its own catchment area that can be pumped over the side. .

Agreed, a very bad design. Pre made shower sumps are available at marine retailers and include the pump and float switch. Another option (that I have on my boat) is a dedicated pump that can run dry for a few minutes. Switch it on, take a shower, switch it off. Water is pumped directly overboard without a sump or float switch.

This change should be on the "to do" list, near the top.

[Cheechako]

Can you see fuel in the bilge? It will float on top of the water. It sounds to me like you have a leaking tank, but if thats the case you should see fuel, does your boat have a place fuel could leak into without going to the bilge.. a pocket in the bilge structure somewhere?
Had a couple small boats with showers to the bilge, I had no issue at all with it. Just keep a screen in the shower sump to catch the hair. The detergent keeps the bilge nice and clean. Why would a "premade" shower sump smell any better than a bilge? Especailly seeings how the often spill over into the bilge when on a heel....

[Kettlewell]

Why would a "premade" shower sump smell any better than a bilge? Especailly seeings how the often spill over into the bilge when on a heel....

Because you don't leave the shower water standing around for days or weeks in the sump like it will in the bilge. At least any bilge I have ever had always leaves an inch or two of water down there. Shower water not only contains soap but various organic stuff like skin particles that washes off your body and will biodegrade down in your bilge. Biodegradation = smell. You wouldn't finely grind up chicken skin and throw it into the bilge, would you? A good shower sump will pump almost completely dry and then I wipe up the rest so it is dry--no standing water.

[Cheechako]

I guess I've never seen a good one. Only seen those cheap white plastic things with the micro bilge pump in them. On my bigger boats I just had a proper pump and small strainer connected to the drain going directly overboard from a switch in the shower.
You actually get down there and wipe it clean after each use? OMG!

[westwinds]

Originally Posted by cal 39 guy

Shower does drain in bilge and it was a stink zone.
did a 3 hr bilge flush with fresh water. hopefully that will do it


i got access to one long side of fuel tank (75 gallon aluminum) and saw
no leakage. also the tank vent hose looks like automotive heater hose.
and 1/2 the upper section of tank fill hose is clear.
(maybe vinyl hose?)

Is this one continuous filler hose? If lower part is discolored then likely there is a leak here because discoloration indicates a really old hose. Diesel is a light oil and dust will stick to it. Look for dust that sticks to the hose because diesel has seeped through the hose. If the leak is really a bad one, look for a streak down the hose that is really clean, as the diesel will in this situation, wash dust off the hose. Feeling around with your hand may also help you find a leak, just smell your hands for diesel. A mirror on a stick available from an automotive parts store can also be used to look for leaks. While you are at it, check the vent hose.

Another thing, check the engine compartment because diesel from a leaking hose can get into the bilge from here, especially since the cutless bearing is supposed to leak a drop of water or two every minute the engine is propelling the boat and this water can flush diesel towards the bilge. A diesel filter can leak here too. I have also seen high pressure fuel lines from the injection pump to the injectors fail because of a crack. Check here for diesel. If the engine is running, then these high pressure fuel lines will readily show a leak. Be careful of the belts because a belt can take off a finger if the engine is running not to mention tear your clothes off.

[Kettlewell]

You actually get down there and wipe it clean after each use? OMG!

It's quite clean since it gets wiped after each use. But, we take 95% of our showers in the cockpit under the hard top and so the water goes down the cockpit drains.

[westwinds]

A shower will sometimes have its own seperate little bilge area and pump. Maybe you will want to make one up for your boat. It takes very little organic material to make water smell after a few days. All the oxyten is taken out of the water by bacteria and then the organic material, instead of becoming carbon dioxide which is bacterial waste product, becomes volatile organic acids. Vinegar is the simplest, but the more complex organic acids really smell. There are also other unpleasant smelling waste products from the anaerobic bacteria in the bilge.

[rwidman]

Originally Posted by Cheechako

........... Why would a "premade" shower sump smell any better than a bilge? Especailly seeings how the often spill over into the bilge when on a heel....

Think about this for a while. You should be able to figure it out.