July 2022

 July, 10

I've spent some time cutting the tongue and groove "V" boards for the ceiling while I wait until the parts come in to finish the tanks.  Originally I was going to weld all the fittings onto the tank using HDPE pipe.  As it turns out HDPE sheet and HDPE pipe are not generally weldable to each other.  I've since ordered some impressive looking bulkhead connectors that have 1.5" NPT threads on either side.  The large ones for the black water tanks have arrived and I was able to take measurements to make a connector tube to connect the tank on the port and starboard side together.  On top of this tube, I will put the pump-out tube via one of those bulkhead connectors.  I did some experiments to figure out how best to make this tube to connect the tanks.  I used a "V" bit in my router and cut a 90 degree "V" where I wanted to bend the HDPE sheet 90 degrees.  I did not cut all the way through.  I left an 1/8" and used the hot air welding gun to soften up the joint so I could bend it to shape.  As I got to about 75-80 degrees, I had a narrow groove that I was able to heat to welding temperature and then close the gap to make the 90 degree bend.  I held it in place until the HDPE cooled.  Then I added a weld down the inside.  In this way, I was able to make a square tube with only one real seam.  Also, the rounded corners look real nice.

I am holding the tube in a jig to ensure that the sides stay at 90 degrees while the weld joint cools.  I just made the next to the last weld.  

The completed tube that will connect both tanks across the centerline of the boat.  The  pump-out pipe will connect to the top (side as pictured) of the connector tube since that is the lowest place in the tank system and equally close to both tanks.

July 30.

This is how the connector tube is suppose to fit.

View from inside the tank showing how tight I've fit that tube,

A view from the other tank. I'll cut a groove where  the weld will go.

This will be the pump out tube in the middle of the connector.  It is the lowest part of the tank.  

This is the external gage that will let me know how full the tanks are.  Nothing to get fowled here.

Final installation and welding of the connector tube. I've put rubber flashing over the longitudinal where  the tank will sit.  This will keep condensation, from the tanks, off the wood.  I did the same under the I-Beam that acts as a mast step girder as well as bolts to the ballast keel. 

I like to illuminate my work.  

Filled with water.  Wait... is that a leak!  Actually I had a leak on both sides. This one was easy to fix.  The leak on the port side was a disaster.  I spent an entire day working on it and just could not get it fixed.  Finally, I stuffed rags in the limber holes and flooded the section of the hull where the tank is hoping to see water enter the tank at the leaks.  It's pretty tight there so it really did not take much water and it only took a little to see where water was coming into the tank.  A lot easier than figuring out where the water was coming out of the tank.  Even knowing exactly where the leak was, I was unable to fix it yet.  I completely ground down the welds and re-welded three times.  I still have 3 small beads of water percolating up from very small pin holes.  I think my issue is the dampness of the wood beneath the tank.  When I try to re-weld, moisture (steam) seeps up creating gaps in the weld.  I've marked the small pin holes and I'm going to let everything dry out over the next few days and try again.  At least I have a rather easy method of finding the leaks.