Replaced my blackwater tank sender last night

echandler1971

If you like Mike Rowe's Dirty Jobs show, then you'll love changing out the original xintex-fireboy blackwater tank sender on a 16 year old 360 FV. First indication it was going to suck was when I unscrewed the sender from the tank and pulled it up only to see a wire and no tube. The tank top had sunken down some while at the same time, the sides had poked inwards. This forced the pipe against the side of the tank harder and harder over the years and at some point, snapped the tube off the cap. To lift the tube out in such tight quarters, I had to raise it up into a blind alcove next to my rear seat amongst a multitude of pipes and wires. Of course, it got hung up in those. 
With my hands dripping in liquid death, I managed to get the thing into a garbage bag that my wife had ready for me. I then washed my hands as if preparing for surgery.
The new sender went in easy until it came time to screw it down. With the receptacle on the sunken-down top pointing the pipe right into the side of the tank and me not wanting this one to snap in a few years, I had to cross thread it in to make it go vertical.
The deed is done, but I'm going to have lasting mental trauma for a while. 

echandler1971

Technical - plastic tank has 1 1/2" NPT opening, which means the sender needs to be almost 1 3/4" wide (strange, I know). I replaced with a KUS Holding Tank Level Sender -SHS/SHST 28" for my 29" tall tank. I had done the same with the water tank sender - using a KUS as well. Both are attached to separate Yacht Devices YDTA-01s that connect to my N2K network. It's literally just 2 wires connected to 2 wires on the YDTA-01s - wiring is dead simple.

echandler1971

Aqua_Aura

Now that I have a nmea network I wanted to add tank senders but I do not have any fittings currently on my tank. I assume your tank already had them? What fittings would I purchased and how would they attach? 

echandler1971

So yes, my plastic tanks had a female 1 1/2" threaded fitting that sits above the tank wall (as pictured). This means it's actually closer to 1 3/4" wide for the fitting for a 1 1/2" pipe, which threw me off when looking at the threaded senders out there. I was looking for a 1 3/4" threaded and found none, but it was the 1 1/2" that I actually needed. There are other kits that allow you to just drill a hole in the top and drop the sender in, screwing it down with a flange and 5-6 screws. The senders I use had the option to purchase said flange kit.

The biggest issue with the flange kits is if you want one for your water tank sender, drilling without dropping bits of plastic into your clean tank is difficult and getting those bits out is near impossible if it's mounted in your boat already (and likely full of water). If you get plastic in your black water tank, it matters not obviously.

I could have done better having the flange-mount kit, as the built-in threaded receivers on the tanks both aimed towards the tank wall due to the tanks deforming over the years. If you attempt to thread it in as the fitting would have you, the sender hits the side wall about half way up, making it impossible without attempting to reshape the tank. I made it work by cross-threading against my personal reservations of doing that.