Black Water Tank Type?

[footloose]

I have access to an inexpensive 35 gallon water tank and would like to use it as a new black water tank....is it the same material and usable?

Thanks!

 

[Billylll]

You want to make sure the poly tank is 3/8ths of an inch thick. Also you want the tank to have a high 1 - 1.5" upper dump fitting and lower waste removal fitting. Either a top mounted dipstick of the same diameter can be used to activate and a minimum of 1 3/4 to larger vent at the top of the tank or one at the upper corner or corners 2 vent lines is ideal. There are conversion kits made to install additional fittings as needed. I prefered getting the waste tank with the proper fittings locations when I replaced mine. I also replaced my 2 freshwater tanks with Poly/plastics just make sure they are well supported. Bill

 

[Vic Willman]

It can "probably" double as a holding tank, but note Bill's mention of the wall thickness of the tank. Absolutely no less than 1/4" thick, and the more beyond that, the better.

 

[rawidman]

quote:

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I have access to an inexpensive 35 gallon water tank and would like to use it as a new black water tank....is it the same material and usable?

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Does it have the right fittings for the hoses? Probably not.

You'll need a 1 1/2" inlet from the head (at the top), at least one 1 1/2" outlet for pumpout or a macerator (at the bottom), and a 5/8" or larger outlet for the vent (at the top).

Edit: I see Billylll alread pretty much said that but it's important. By the time you modify the tank, it may be less expensive to purchase a ready made holding tank.

 

[footloose]

thanks all! Good stuff as usaul

 

[Billylll]

I changed my 3 Aluminum tanks 2 water and 1 waste with Poly/Plastic tanks. I have been through this. I only wanted to do it once. All my tanks are 3/8" and supported on all sides.
I also used rubber along both bottom corners to minimize chafing of the tank when or if it were to vibrate. With the plastic tanks you will be able to use Raritan's great 4 tank monitoring system. Other than an occasional tweaking of the calibration the sensors never need cleaning they are on the outside of the tanks.
Bill

 

[Vic Willman]

Foot, if the tank doesn't have the correct-sized fittings in the right places for the installation, you can always get one of these kits and put them where you need them:

http://www.boatfix.com/shop3/store/listItems.asp?strSearch=relocation

 

[rawidman]

As the owner of a boat with a pretty small holding tank, I would recommend buying and installing the largest tank (within reason) that will fit even if it costs a bit more. Getting a pumpout can be inconvenient and the charge is the same for 14 gallons or 44 gallons.

 

[romey]

Don't what to hijack the thread, but Bill I'm wondering how you got the holding tank and back water tank out of you boat. I have the same boat and it looks likes a big job.