PVC tanks

[skylark]

I built a PVC tank for use as a kerosene day tank for my Fab-All heater.  It seems to be leak free and so far everything looks OK.  The tank is about 4' long and seems to hold about 2 gallons.

The tank is made from 4" PVC pipe with two end caps.  The inlet and outlet were drilled and tapped into an end cap with a 1/4" NPT tap.  The vent was drilled and tapped into the pipe wall.  I was able to find the tap at McMaster Carr, they have a cheap steel tap for about $6 that should be good enough for tapping plastic.  All fittings connected to the tank are 1/4" NPT male and are threaded directly into the plastic using teflon tape.

I spray painted the pipe but DON'T do this, it is scraping off on the hull and making a mess.

The outlet has a ball valve on it. -> 1/4" NPT nipple, 1/4" NPT female/female ball valve, 1/4" NPT to 3/8" hose barb.

The inlet has a hose barb with a fuel line with a squeeze bulb and a Tohatsu fuel quick disconnect female fitting -> 1/4" NPT to 3/8" hose barb.  This is used with a 3 gallon fuel tank painted blue for kerosene with the Tohatsu quick disconnect male on it.  The fuel tank is placed on the hard dodger above the day tank and a few squeezes on the bulb and it siphons to fill the day tank.  The vent is higher than the position on the hard dodger so it automatically stops siphoning when full (theory must be tested here).

The vent has a hose barb and the vent tube is clamped up on the hard dodger.

Actually this post is not so much about my day tank as it is about using PVC pipe as tankage.  I am thinking about getting some 6" pipe and making a water tank that would gravity flow into my galley sink.

Volume calculations:
There are 151 cubic inches per foot of 4" pipe, which converts to 0.653 gallons per foot length.
There are 339 cubic inches per foot of 6" pipe, which converts to 1.47 gallons per foot length.

To make a good fill tube, I would like to find a 6" x 2" x 6"  tee, preferably a street tee so I could cap it off.  Then I would add a 2" riser pipe with a removable cap, maybe a threaded cap if I can find one.  Run the outlet hose down to the galley sink with a ball valve and small copper tubing outlet pipe over the sink.

I love plumbing when it doesn't leak.

Anyway, first indications are that the drilled and tapped NPT threads are tight and not leaking.

[AdriftAtSea]

I hope you used Schedule 80 pipe for the tank, rather than the lighter Schedule 40 pipe.  I think the Schedule 80 would be better, as it has thicker walls for the tapped holes.

[skylark]

Schedule 40 worked fine.