Fuel Tank Replacement- Making Progress

[Ross]

Aluminum tanks serve the highway trucking industry very well and reliably in about the worst possible conditions.

 

[Ralph Johnstone]

More on Vapour Permeation ........................

I can certainly see why you used aluminum in this application - dimensional stability, intricate shape, and $COST$.

I was quite interested in the permeation characteristic as I have never had any diesel smell from my 10 year old poly tank in our 1999 H310. Mind you, our waters are pretty cool here (cooler fuel tank resting on a cold hull) which may account for the cooler tank and lack of permeation. This may not be the case down south for permeation.

Took a look on the Moeller web site and found the following reference to gasoline vapour permeation only but no reference to diesel fuel. Hopefully the longer chain molecules in diesel reduces permeation to a minimum. Always interesting to know.

Now that I've convinced myself of that ..... I can get to sleep tonight.

 

[SailingHarry]

How about the fill connection?

Main Sail,

As I mentioned in a separate posting a while back, I too am in need of a replacement tank. I'm not going custom (the original vendor from 1979 still makes the tank!), but he will make minor changes for no or minimal cost.

Here's my issue. I have not yet had my boat a year, and so have only fueled twice -- so I don't have a lot of experience to draw from on this matter. However, on both occasions, the filling fuel has apparently "frothed" in the tank, and that froth then found its way to the vent and out to the deck. The first time, I caught it before it hit the water but it still made a mess. The second time, I was prepared and caught all of it right at the vent. Note it is a 20 gallon tank, 27" x 16" x 12".

So, for the question. I swear I read someplace that making the fill have a "dip tube" much like a pickup would have, going down say 2/3 of the tank height, can stop this issue, but I can't find the mention again. Your pictures and story don't mention the fill portion of the system. Did you do anything to prevent this issue, or is there something else I should consider that I am missing?

Thanks for any response. Your system looks VERY sharp! Mine has a lot fewer connections -- no heater, no re-circ system (yet -- but maybe that is worth planning for), and my Volvo MD11C is plumbed without a return to the tank (which is how the Volvo factory shows it!).

Harry

 

[Steve Dion]

Here is one option.

http://shop.hunterowners.com/detail.htm?group=766&cat=1113

I think that we also had a overfill capture available on the SBO site. Maybe Dave G can pipe in and let us know if they are still available.

 

[Stu Jackson]

MHowever, on both occasions, the filling fuel has apparently "frothed" in the tank, and that froth then found its way to the vent and out to the deck. ... I read someplace that making the fill have a "dip tube" much like a pickup would have, going down say 2/3 of the tank height, can stop this issue, but I can't find the mention again.

I had the same issue at first. Our solution was to simply slow down the fill rate right from the pump handle. We refill every 20 hours with 10 gallons of fuel (nominal) in our 23 gallon tank. Simple solution with no extra work.

 

[Roger Long]

However, on both occasions, the filling fuel has apparently "frothed" in the tank, and that froth then found its way to the vent and out to the deck.

I had that problem constantly the first season with my boat. The vent had a loop in it and a low spot where fuel collected to block it. Once that was cleared out, the problem was still there but much less severe.

My tank is under an opening hatch in a seat locker. I put a "Tee" fitting on the vent with a short pipe nipple, ball valve, and plug to keep debris out. This is primarily for use as a sounding tube but opening it during fueling avoids any hint of frothing.

 

[RAD]

slow fill ups

I have the same problem and I just siphon from a 5 gal. fuel can into the tank even with a fuel whistle because your filling at such a slow rate its hard to hear the whistle and I have thought of adding a tee and a valve to redirect the vent into my cockpit so during a fill up any over flow would be in the cockpit and not in the water..... I was using the stick on the hull can once and it unstuck at the worse possible moment

 

[Maine Sail]

I have the same problem and I just siphon from a 5 gal. fuel can into the tank even with a fuel whistle because your filling at such a slow rate its hard to hear the whistle and I have thought of adding a tee and a valve to redirect the vent into my cockpit so during a fill up any over flow would be in the cockpit and not in the water..... I was using the stick on the hull can once and it unstuck at the worse possible moment

Sounds like you both have a low spot in the vent hose. This should not be an issue with a properly routed vent hose that always has air in it and no low spot to trap fuel. If you trap fuel in the vent hose the incoming fuel will displace the fuel in the vent hose with the air in the tank and burp or spit it out so the tank can fill and replace the air with liquid...