[C320-list] Bilge Diesel

[Doug Treff]

Brian,

I do know that my yard manager advised me last fall when topping off 
that I should leave a little head space in the tank for expansion. It 
was a very cold November day and I was topping off a half full tank to 
reduce the air trapped in the tank over the winter. He told me that a 
common problem is that fuel will expand when we get a warm day and start 
leaking out the vent. However, I wouldn't think you should have any 
scenario where fuel would leak IN THE BOAT due to expansion as long as 
your vent is clear.

Last year I identified a leak with my sender unit and (I think) that I 
tackled it. Keeping my fingers crossed this spring that it's fixed. The 
tank ONLY leaked when I filled it all the way, and then periodically 
when on a starboard tack until I had used enough fuel to keep the sender 
unit from being an issue. This could be be your problem if you topped 
off so much that the fuel level went up the fill neck. Keep an eye on it 
this year and see if the leak stops once you've used a few gallons of 
fuel. Then if it reappears when you're sailing it could be the sender 
unit. Alternatively, if you have an easy way to remove the fuel (into an 
approved container) to about a half tank and see if your problem goes 
away, this could be a clue for you.

I've not tackled the tank replacement job, but others here have, and 
Jeff Hare posted just a couple months ago that he had finalized a new 
tank design that would have a slightly higher capacity. Haven't seen the 
follow-up post detailing his work, so no idea if he's done the job yet. 
As always, Jeff is very thorough and his projects are always first-rate. 
I'm sure an article will be forthcoming when he has a chance.

I'm surprised he hasn't answered in this thread yet. Maybe he's stuck 
down in his lazarette locker waiting for one of us to rescue him... ;-)

A new fuel tank is definitely on my "project list" but I haven't set a 
date yet. Kinda waiting for results on Jeff's install first. Hoping the 
sender unit fix will buy me some time. Plus I will have to temporarily 
remove my air conditioner unit to make room for the old and new tanks to 
pass through.

Please share the outcome of your troubleshooting with the group.

Cheers,

---
Doug Treff
Catalina 320 - 1996 - September Song - #350
http://savvysailor.blogspot.com/
doug at treff.us

On 2015-04-28 16:56, Amiraults Family wrote:

> When removing antifreeze from the bilge on Sunday in preparation for 
> launch
> May 02, I found a little diesel in the aft section of bilge exposed 
> when
> lifting the inspection plate on the floor the main cabin. I cleaned 
> this. I
> was at the boat again today (Tuesday) to do the hull wax and buff to 
> find a
> ½ cup more fuel in the same area. Where I can actually trace back the 
> leak,
> it is coming from the starboard side and from under the floor of the 
> head.
> In the aft cabin the leak is further back than the plastic water tank. 
> It is
> coming from the area of the fuel tank, and not the engine.
> 
> I filled the tank on the hard in cold November. It is now +22 C in 
> Ottawa.
> It is possible that there is expansion of the fuel and a resulting leak
> other than in the actual tank wall. Launch cannot be delayed, and I 
> must go
> in with club launch Saturday so I cannot further address this until 
> Monday
> May 04. At that time I want to move quickly. Currently the leak is 
> slow, and
> I have a bilge sock positioned in the way of the flow.
> 
> In the event that it proves to be the tank, if someone reading this has
> already addressed this matter and done a tank replacement, I would
> appreciate insight into the process, tips to make the remove/install
> progress more smoothly, and 'should have dones' that I should be
> considering.