Holding Tank Capacity

[TBOT422]

Has anyone ever tested the waste holding tank capacity? The owner's manual says it's supposed to be 22 gallon. I have been concerned with how quickly the waste tank seemed to fill up for some time. I wasn't sure if it was a guage inaccuracy, or the amount of salt water induced with every flush, or something else. Today, I had the opportunity to measure the water it took to fill the tank. I was only able to pour about 15 gallons into a supposedly empty waste tank. We had been offshore and drained it by opening the Y-valve. Now, I suspect that either the tank is really not 22 gallon (it does look pretty small), or their is a good deal of sludge or buildup of some nature in the tank that does not empty.

Any thoughts on how to verify the tank's capacity or to clean out whatever is preventing it from being usable?

Thanks

[KenKrawford]

When I first got my boat I filled the holding tank with a measured bucket of water. It took slightly less than 20 gallons to fill it.

[PaulT]

I tested the capacity of the holding tank of my 2005 350 (hull 320) and found it to be 18 gals. Also found that the tank guage, even after recalibrating, shows it "full" at about 10 gals. An earlier model 350 in our marina (2003 ?) has a holding tank with a nominal capacity of 26 gals.

PaulT
Second Wind
Hull 320

[AynB]

I can not address the size of the tank, I've never taken the time to measure it.
I can, however, describe the method we use to clean it out - not pretty, but it works.
We found that after sailing in Canadian waters for six months, where we just dump as you would offshore, that the deck fitting process simply would not work. I tried the top flush and bottom flush tricks to no avail. I ended up building a tool.

Basically I took four sections of threaded lamp rod and three double female fittings to make a take-apart tube that will go down the deck suction tube to the bottom of the tank. At the lower end of this tube, I put a 90 degree brass fitting, female to male , and flattened the male to make a better spray pattern. At the upper end of the assembly, I put a 10" section of clear flexible tubing, then a standard hose inline shut off and the fittings needed to couple all of this together.

In practice, I assemble the gizmo, hook it up to a hose at the pumpout station then turn on the water flow at the 'handle' until fluid rises up the pumpout tube. Shut off the water, let the water settle. Repeat until I estimate that a few gallons have gone in and try to pump out again. Also while the water jet is flowing, I turn the gizmo ( using the flex tubing ) to get all areas of the tank bottom.

After a half hour of this, I can get the tank to take fresh water and pump out visibly clear water.
Disassemble the gizmo, bleach it and bag it for next time.

Typographically the tool looks like this :

HHHHHHHHHOSEHHHHH SHUTOFF FF FLEXTUBE FF BRASSLAMP FF BRASSLAMP FF BRASSLAMP FF BRASSLAMP (90)

Where FF is either a double female fitting or other device to change size / thread / coupling.

I am certain I have a photo of this beast somewhere. I has served us well for three seasons now.
Al
Halona #17

[TBOT422]

I took some measurements of the waste tank today as best as I could. From what I was able to measure, the tank is 23 inches tall. At the forward top edge, I measured a total of 12 inches of depth. I measured 11 inches width of the main section at the bottom and 3 inches for the cutout around the shroud fitting for a maximum width of 14 inches. If the tank were completely rectangular and did not have a cutout around the shroud fitting, it would be 23 x 12 x 14 or 3864 cubic inches. That equates to 16.7 gallons. Of course the tank cutouts and tapered shape would make it less than that. I only measured it to be 9 inches deep at the bottom versus 12 at the top.

When I take the tapered shape and the cutouts into account, I calculate 2967 cubic inches or about 12.8 gallons. I'm sure my measurements are not precise as it is difficult to get access to all edges of the tank, and I'm assuming how the aft side and back side are configured. Clearly it's bigger than 12.8 gallons since I poured about 15 gallons into it, but there is no way it is 22 gallons as stated in the manual.

It also seems that all C350's do not have the same waste tank, since some of you measure 18, 20 or even 26 gallons.

Based on my crude measurements, at least I don't think I need to figure out how to clean it out. I think about 15 gallons is all the capacity that's available.

Thanks

[dennisferriello]

Hi, my name is Dennis. I supply Catalina with there gauges.
I just joined your forum and if anyone needs help with there monitors please get hold of me.

What unit do you have with your 350? If it is our unit and you calibrate full
it should be full if the external foil goes to the top of the tank and in fact it is our unit.

If the foil only goes to say 3/4 the way up that is where full is going to show.
Can you see if there are foil strips on the tank and what does the panel have for a name on it?
I would be glad to help you get a true full reading.

It is possible it is a Snake River Acugauge panel, I can also help you with that.

Here is what we show in our records for 2005, verified by a letter from Catalina back in 2005

they had a 350 B which was replaced with 350 C

350 A
 
FWD WATER
AFT WATER
FWD WASTE
 
350-C
 
FWD WATER
MID WATER
AFT WATER
FWD WASTE

Dennis Ferriello
http://www.ferriellosales.com
dennis@ferriellosales.com
435-656-0042

PS since there was 3 - 350 models at one time it is possible that the tank sizes are different?

[TBOT422]

Warren Pandy of Catalina was able to provide me with the engineering design drawing for the Catalina 350 waste holding tank. Based on the dimensions on the drawing, by my calculations, the holding tank capacity should be about 20.4 gallons. Of course, these dimensions are to the outside of the tank, so the internal volume would be less. I don't know what the wall thickness is, but if it was 1/8", the capacity would be about 1 gallon less.

Given that I only was able to pour about 15 gallons into a supposedly empty tank, I may repeat that test and be more careful with the measurement of water that I am adding.

It may be possible that some of the early models have a little more capacity as the revision history shows some dimensional changes in 2002.

[dennisferriello]

Warren Pandy of Catalina was able to provide me with the engineering design drawing for the Catalina 350 waste holding tank. Based on the dimensions on the drawing, by my calculations, the holding tank capacity should be about 20.4 gallons. Of course, these dimensions are to the outside of the tank, so the internal volume would be less. I don't know what the wall thickness is, but if it was 1/8", the capacity would be about 1 gallon less.

Given that I only was able to pour about 15 gallons into a supposedly empty tank, I may repeat that test and be more careful with the measurement of water that I am adding.

It may be possible that some of the early models have a little more capacity as the revision history shows some dimensional changes in 2002.

==============================================================
Warren is a great guy. I was with him a few weeks ago and we see in next week.
Dennis