1986 19' Atlantic rebuild

[Fuzz]

Looking at the last picture my first thought was "man you work clean"

[goingbogueoutdoors]

Rubber finally came in for my tank area. Got tank set and foamed on both sides, as well as all the bilge area squared away. The sea chest was a bit awkward but finally was able to commit to a layout that was functional. Tank sending unit and all three rule pumps with be run together on the portside, around the transom to the rigging tube. Fuel on the starboard side, then shoots upward to the rigging tube.

Still need to pull a little bit of slack on the fill/vent tube to eliminate the low spots. Also still running bilge pump to the starboard side

[Jeff]

Really well done!!! Jeff

[Fuzz]

Bad news, sorry!
That looks like a plastic tank. If so they are NOT supposed to be foamed in. They will expand up to three percent when filled and need room to do so. The Moeller site has some info on this but they do not sound like it is the end of the world. You might want to go there and read what they say.

[goingbogueoutdoors]

Bad news, sorry!
That looks like a plastic tank. If so they are NOT supposed to be foamed in. They will expand up to three percent when filled and need room to do so. The Moeller site has some info on this but they do not sound like it is the end of the world. You might want to go there and read what they say.

The tanks top is the most “flexible” area of it. The sides being so narrow, I foamed and left ~2-3 inch gap on top for expansion and contraction of the tank. We did one like this previously, and have a few others do the same:

[Fuzz]

You knew about it and have done it that way before with success so all good then. I just did not want to see it and not say something. To be honest I do not know what makes the tanks grow, maybe just fluid weight not being supported??

[TomW1]

Fuzz, the plastic tanks expand due to thermal expansion. Once enough gas is used it is not a problem. Tom

[fallguy1000]

The only comment from me on the tank is it should be tested at 2-3 psi overnite before sole goes down with lines on. Capping the vent and fill can be tricky. I did not test the fill cap, but plugged the line instead. I had one leak on one of the two tanks at my test fitting. Once fixed was fine. It is a little unnerving because the tank gets pretty big. It will probably crush that foam on the top some, but should be done.

I believe, technically, a mechanical fastening is required, but as long as the tank doesn't move after the test; should be fine.

Back in the day, plastic was not impervious to fuel odors and so the reason Fuzz did not like the foam is because it provides a potential (or use to before epa required plastic improvements) for fuel vapors to collect. And, I don't recall whether it is allowed now under abyc. But their tank rules need revision afaic anyhow.

For me, personally, I am afraid of fuel vapors as having singed my eyebrows once to standing in a vapor pool and lighting a groundfire. No wind that nite, and my one match went out. Went in the house, got distracted and went back after some time had past and nearly exploded myself (okay I did).

Fire is the greatest risk to my boat, so anything I can do to mitigate I will. A fire 50 miles offshore is a big problem for all mariners and can result in loss of life. A fire in a marina is also damned bad. Go burn a piece of boat core and skin and epoxy in an outside fire pit sometime if you got no fear of boat fire. It goes up kinda like a firework or close.

For tank testing, I also had a gauge fail. So, if you see the tank balloon up and no gauge reading; be careful. For me, I stopped cause I got nervous and discovered the cheap Chinese crap.. and spent more money on a better one..

[fallguy1000]

Oh, the tanks grow due to thermal change. So, tank installed at ambient 70F, then you go out on a 95 degree day with the sun beating down and the sole hits 105F and now the tank is 35 degrees warmer. The engine supply and fill are sealed, and so only the vent line is open. The fuel vapors escape, but the plastic itself has thermal properties that also make it expand quite a bit.

And it grows in all directions. So the bottom panel of the tank grows upwards; the sides in a foamed in tank grow inwards? and the top grows upwards. In a bolted tank, the sides grow outwards. If the sides grow outwards into the foam; they will crush it and reduce the holding power.

Volumetric growth is always pretty significant...

So, another thing to consider when foaming in is how does thermal expansion of the plastic work...

[OrangeQuest]

Looks like the foam around the tank complies with USCG regulations. I would be a little concerned about the vent hose dipping down as it exits the stringer and could possibly be a liquid fuel trap and could cause blow back when filling. That and, from the angle of the picture, the fuel line may be a little high where the chase tube comes into the bilge area, could cables or wire contact it? Could all be just the angle of the pictures. Overall looks very well done.

Curious about the bilge pumps in the small box? Is that for ballast control or live wells?