Getting at the holding tank

[Justin_NSA]

I want to install a level indicator, but before I can even order the parts I need to know what my holding tank is made of. The drawings say it could be plastic or aluminum - big help.
It's sandwiched between the aft berth bulkhead and the stern. The port half-wall would have to come out unless I can access it under the batteries in the aft lazarette. Has anyone added a sensor to their 30T tank and know the best way to get at it? Thanks.

 

[Justin_NSA]

I found this mod on the SBO site. It gives me some idea how to access the tank. It looks like Brian's was aluminum. The last picture seems to show that you can get to the existing tank from under the battery locker (?)
You almost want to do it his way to be sure the old tank isn't leaking although you think you would smell it if it was

http://hunter.sailboatowners.com/mods.php?task=article&mid=24&aid=8134&mn=30_88-94

 

[JamesG161]

install a level indicator

This is a surprise to me. I thought every Hold Tank had to have a level indicator of some variety.
This sensor can be used in plastic or Aluminum.
http://www.wemausa.com/sensors/level-HoldingTank.shtml#.V8Omk2XTQo8
My 8" sensor (your size needed too) has 2 years of non-clogging accurate service.
I would get the LED gauge since that is why the sensor works (encased micro switches).
Jim...

 

[Peggie Hall HeadMistress]

USCG regs do require that every tank has some means of determining when the tank is at least 3/4 full. If the tank is in a location and made of a material that allows visual inspection, no gauge is needed. If not, one is needed. The SeaLand TankWatch I is the only one that exists solely to meet that minimum requirement. All others provide some means of letting you know how full the tank is getting. Wema is popular among boat builders because it's cheap.

If your tank is aluminum--ANY metal--you need to know that urine is so corrosive it'll turn an aluminum--any metal, even 316 SS--tank into a colander in an average of 10 years. The first leak will typically be a weld in a seam or fitting within 2-5 years...that's the time to replace the tank because that will be only the FIRST leak. In which case, a Wema should last until it does start to leak...at which time you can upgrade to a Profile Solo Profile Tank Monitors when you replace it with a top quality plastic tank, which you'll want to get from Ronco Plastics. TOP quality thick-walled water and waste tanks for a very reasonable price and has more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. Ronco Plastics Marine Catalog http://ferriellosales.com/

 

[Ken Cross]

Our tank is located in the head cabinet beside the toilet.
One tool you might consider is a small USB camera that you can stuff in small holes like this one:

https://smile.amazon.com/Smartphone...771815&sr=1-3-spons&keywords=usb+camera&psc=1

At less than $20 I'm sure you can also find plenty of other uses for it as well.
The similar one I have works pretty well.
Ken

 

[PAC3142]

For what it is worth, I had a 1990 30G and it had a plastic tank. Also, for what it's worth, my 1994 37.5 has an aluminum tank. On the 37.5 I have to remove the batteries to take out the hatch to access the holding tank. That doesn't take much time to do. Far less time than it takes trying to clean out toilet paper from the 90 degree fitting at the inlet to the tank. Don't ask me how I know that.

 

[Justin_NSA]

For what it is worth, I had a 1990 30G and it had a plastic tank. Also, for what it's worth, my 1994 37.5 has an aluminum tank. On the 37.5 I have to remove the batteries to take out the hatch to access the holding tank. That doesn't take much time to do. Far less time than it takes trying to clean out toilet paper from the 90 degree fitting at the inlet to the tank. Don't ask me how I know that.

Thanks for that glimmer of hope
I'm going to pull the batteries and open the hatch to see what I have to work with once I haul her out for the season. Hopefully it's plastic, I won't have to worry about leaks, and I can attach the level sensor to the outside of the tank. Then I hope to clean, coat and label all of the battery leads

 

[Justin_NSA]

Update and question (opinions) -
The tank was accessible from under the batteries. Turned out to be aluminum so I ordered the internal PVC probe. On the outside it looks like 1/2" pipe capped on the end. Probe is installed. So far, so good.
I have question, soliciting opinions on mounting the display panel over the head. It has a 3/4" deep circuit board behind it. Rather than hack out a large cutout on my fiberglass bulkhead, I want to buy some 3/4" thick material and cut it out instead. Then I only need 2 holes to attach it from behind ( I have access thru a storage compartment) and 1 small hole for the 4 wires coming out.
So for aesthetic reasons, should I go with a wood or white 'glass look? I can pick up a piece of HDPE easy enough. I have some scrap birch, oak and cherry wood I could perhaps stain to match the teak. A small piece of 3/4" thick teak would be hard to find The display panel is pretty small.

 

[Ron20324]

Justin, how about going to an awards shop or craft store and get an already-made plaque? Maybe mount any type you choose with double-face tape and nee only one hole.

 

[Justin_NSA]

That might work as well Ron. I'd like to stain to match my teak if possible. I'm not sure which wood will stain closer to the same look.

 

[MitchM]

take your piece of teak to a good unpainted- furniture shop, and they have little jars of color to sell which will match any wood .

 

[Amos Cape]

I used a light switch cover made of wood for my thermostat on the air conditioner. It turned out looking good.

 

[Justin_NSA]

Slow going on this project with the weather:

Question: what's the best double stick tape for HDPE to fiberglass? The thinner the better. It's already 3/4" thick.

I decided to go with HDPE to minimize the overall look of the black faced display. I'll post a pic when I get it mounted.
I want to minimize the 'damage' to the bulkhead which is why I'm doing it this way instead of hacking a rectangular hole for the circuit card. This way I'm hoping I only need a small hole for the 5 wires to pass thru.
I've installed the internal tank sensor, the electrical subpanel in the port laz above the batteries, and routed all the wiring. I'll hook up temporary power to be sure it works before a reinstall the batteries above the tank