tank monitors

JSmith · Post by **JSmith** » Sun Nov 18, 2007 9:46 am

What's the recommended tank monitor for a waste tank- I would assume def one with no inside floats, etc! I searched the forum but could'nt find any info. This would be for a plywood/epoxy tank.

deckhand · Post by **deckhand** » Wed Nov 21, 2007 2:48 am

make small (1/2" wide or less) strip from top to bottom completely out of fiberglass. It would be transparent and let you see the level in the tank. Simple and fool proof. The other way to do an electronic-less gauge is plumb in a piece of clear tubing into the bottom of the tank and let it run along side. The level in the tube is the level in the tank.
I'm going with the clear fiberglass.

JSmith · Post by **JSmith** » Wed Nov 21, 2007 7:28 am

Sounds good- not sure with my location I'd be able to see a sight gauge .The clear fbierglass sounds better- I can imagine "stuff" clogging the tube.....

Figment · Post by **Figment** » Wed Nov 21, 2007 10:36 am

The white thing with the black ring and the wires is a three-level tank monitor. Essentially three small float-switches on sticks of different lengths. I'm pretty sure it was made by SeaLand, and I don't recall that it was wildly expensive.

In the "bonus" category, the unit includes a vent fitting, and leaves you with a nice big cleanout port if the need should arise in the future.

Hirilondë · Post by **Hirilondë** » Wed Nov 21, 2007 6:13 pm

Figment wrote:

The white thing with the black ring and the wires is a three-level tank monitor. Essentially three small float-switches on sticks of different lengths. I'm pretty sure it was made by SeaLand, and I don't recall that it was wildly expensive.

In the "bonus" category, the unit includes a vent fitting, and leaves you with a nice big cleanout port if the need should arise in the future.

Its called "Tankwatch 4" (reads out as empty, low, mid and full) and is made by Sealand. I use them all the time for holding tanks. It can come with or without the vent fitting. I usually opt to use a separate vent fitting as the vent line needs to be removed before the unit can be unscrewed. It is pricey, but a very reliable unit. The sensor floats with the exception of the one for full come 22" long or 45" long and can be cut to any length desired. So in effect you decide what the other 3 read outs mean.

http://www.sealandtechnology.com/produc ... asp?pid=53

JSmith · Post by **JSmith** » Thu Nov 22, 2007 7:55 am

that looks great. I actually have 2 vent fittings on either side of the bow so I'll get the one w/ no vent. The tank will be aabout 35 gal under the v-berths shaped to fit the hull.

Hirilondë · Post by **Hirilondë** » Thu Nov 22, 2007 9:25 am

JSmith wrote:I actually have 2 vent fittings on either side of the bow so I'll get the one w/ no vent

By vent fitting I meant the fitting the hose attaches to on the tank, not the boat. If you choose to use 2 vents and not tie into the Tankwatch unit you will need 2 fitting on the tank itself for the 2 vent lines. This however is how I would do it. I also use bullet connectors for the 4 wires of the unit at the tank to easily disconnect the wiring. I label the 4 wires at each side of the connection to avoid confusion when reconnecting. Now the removal of the Tankwatch unit from the tank is a simple unscrew and remove. As Figment has said, this makes your Tankwatch 4 a clean-out and inspection port as well.

JSmith · Post by **JSmith** » Fri Nov 23, 2007 7:27 am

I'll def have 2 lines- I think run the line from the port hull vent to the stb side (top) of the tank and the opp for the other. On the tank end there would be hose barbs for double clamps.

deckhand · Post by **deckhand** » Sat Nov 24, 2007 2:03 am

That gauge set up looks great but for the cost of that monitor ($200) you might as well just get a completely translucent poly tank ($100). It would cost less, have completely fool proof level reading, and not rely on electricity. Don't get me wrong, I love my gauges, but on things like engine temp senders and speedos. When it comes to non flammable liquids, I'm betting on sight.

35 gallons is a BIG waste tank! What boat is this going in?

JSmith · Post by **JSmith** » Sat Nov 24, 2007 8:06 am

It's for our Alden challenger 38. I went through the ronco plastic catalogue and really found nothing that fit without wasting (sorry) alot of space.

So after reading Tim's thoughts here I decided I should make one to fit. Not really sure what its capacity would be but based that guess on the tank dimensions and gallons I saw in the catalogue. Most would fit in the space but when I made a mock up I couldn't get it down the companionway!

Most of the time it's just 2 of us but she sleeps 5.... Not sure Cindy is wicked excited I'm going to build rather than purchase.

Rachel · Post by **Rachel** » Sat Nov 24, 2007 7:35 pm

Reading this I was reminded of David V's post about making mockups, which was an illustration of the fact that a tank that would efficiently fit your intended-space wouldn't fit through when you tried to get it into the general area, as in this photo David posted:

But at the same time I thought, "Hmmm, maybe if a person were building a tank, they could actually build the tank up in the forepeak (not necessarily in place, but in the general area), and thus be able to fit in a tank that would otherwise not go through the entranceway. Or along the same lines, perhaps the tank could be mostly built in the shop, but then one or two "last" sides put on after it was in the forepeak.

R.

Hirilondë · Post by **Hirilondë** » Sat Nov 24, 2007 11:17 pm

I've heard a couple meanings for the word "blivet". The one we use at the boatyard refers to an item that fits the situation, but either can't be removed or can't be installed. Great idea Rachel, don't finish the blivet till you get it near by.

Post by **Tim** » Sun Nov 25, 2007 8:49 am

I don't think any non-structural and knowingly non-permanent component or accessory belongs in a boat if it can't be put in or removed through a finished space as required. Knowingly doing otherwise would seem incredibly short-sighted.

I think I'd be less than cheery if I discovered someday that I had to cut apart a used waste tank to remove it just because it wouldn't fit through existing openings.

Hirilondë · Post by **Hirilondë** » Mon Nov 26, 2007 7:09 am

For the most part I agree Tim, but a large holding tank sure is convenient. You can always flush it out well before the surgery of removing it.

LazyGuy · Post by **LazyGuy** » Mon Nov 26, 2007 6:49 pm

Dave, without saying you are wrong, I do not think you can flush a holding tank enough for me to want to take a sawzall to it in the vee berth. I would rather add two tanks that can come out in one piece. Removing a 20 gallon colostomy bag (in one piece) that I had flushed repeatedly damn near sent me chumming more than once.

Quetzalsailor · Post by **Quetzalsailor** » Tue Nov 27, 2007 2:18 pm

Our holding tank monitor is a float switch and idiot light. Not a pleasant task to clean it when it fouls, but survivable. Astonishingly, not as bad as might be assumed, perhaps because we use the digester enzyme additive. The white poly tank is not as transparent after use, nor as well lit, that inspection would work. Neither does 'tapping'. I've been enamored of the external metallic tape / electronic type which you can buy to monitor several tanks with the same readout device...until I priced it.