Water line blocked or hidden valve?

May 7, 2011
205
Catalina 30 Lake Lanier
Our 1985 Catalina 30 mk I has two fresh water tanks, one forward under the vberth and the other under the port settee. I can get water out of the port side tank, but not from the forward tank. I found a 'T' under the aft quarter berth next to the fuel tank. No water comes out of the side I assume goes to the forward tank. If I take the hose off at the valve on the forward tank water flows. I looked at a schematic that looks close to what we have, and it does not seem to show a second valve.

QUESTION: Is there a second valve somewhere I haven't found, or do you think there is a clog/pinch I haven't found? If there is a second valve, where should I look for it?
 
Feb 14, 2014
7,399
Hunter 430 Waveland, MS
Here is a guess...
I am betting your forward tank is at a higher elevation than the port side tank. I am speaking of water level elevatations in full tanks.
_______
If my guess it right, here is what is needed to have both tank's capacity, starting with full tanks.
You will draw from the port tank primarily. When that tank shows Low, open the valve and gravity flow will cause your forward tank to to maintain a usable level in the port tank.
In easier terms, the forward tank is like a spare Jerry can for fuel supplementation.
______
I would leave the valve open and always slowly refill the port tank only using the forward tank. Then close the valve to "top off" the forward tank for a long cruise.

Jim...
 
Jan 6, 2010
1,520
OS,

I have a 1980 C30 & being in the engineering design field, NEVER liked my orig. setup.
Here's why.

With the pump running, yea, the higher V-berth tank drained first into my setee tank & from there to my pump.
This also makes your pump work harder.

So, you now run from one tank thru the lower tank to your pump. This would be fine, but for an area where the hose leading back to the setee tank rises up higher at a point (for me in the hanging locker) than the setee tank inlet line. Here is where my hi-point was before running a bypass line alongside of the setee tank (inboard) & making the dual tie-in connection after the setee tank drain connection (the lower point) & knot draining from one tank into the next.
In this way, your pump's suction is more fluid & your tanks are draining.

With your current setup, you will only drain the v-berth tank to a certain level, as water between tanks will always seek its own equal level. Once the water in your V-berth tank falls below this, you will just suck AIR. So, you end up with a forward tank still 1/3+/- full yet, your setee tank is now empty & your pump is running dry.

On the suction side of a centrifugal pump, any run that loops higher than the pump suction line, can create an air lock. The pump is trying to suction fluid but cannot, as there is air trapped in the line leading to the pump.

Here is what I did. on my boat.

I re-ran the drain line from the V-berth tank so it had no vertical rise to trap flow. It took some drilling to cut down on any line-rise-looping. I routed this line alongside the inboard side of the setee tank. I then connected this line to the drain line from the setee tank (aft the tank). I tied them together with a "Y" fitting for connecting to the pump suction connection.

I don't have this sucking air problem now until both tanks are going on empty. There was not alot of quality control when they built my boat so, when I find these errors, I simply try & find an improvement.

Any fix may not be perfect but, I hope this gives you a better picture.

CR
 
Oct 21, 2016
3
Catalina 30 MkII Harbor WA
1987 Catalina 30 MKII.
Interestingly enough I have the opposite problem: I have a bow tank and a starboard tank. My bow tank runs out first. I can run out of water at the pump and my starboard tank is still mostly full! --- go figure,
tom
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
We have dual tanks, too. One in the stern (larger) is above the cabin (lower) tank. We have two separate valves, one for each tank. Even with both tanks full, it both valves are open, the pump ain't happy. If you have two tanks, simply use one at a time. If you don't have two valves, consider adding another or use Captn. Ron's idea for improvement. I use the "backup" idea promoted earlier: I use the aft 43 gallon tank, and when that runs out, switch to the 28 gallon cabin tank, now knowing I must refill.
 
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Feb 2, 2014
29
Catalina 30 mkII Pasadena, MD
1987 Catalina 30 MKII.
Interestingly enough I have the opposite problem: I have a bow tank and a starboard tank. My bow tank runs out first. I can run out of water at the pump and my starboard tank is still mostly full! --- go figure,
tom
I have the same setup on my 87 Catalina 30 MKII but I have a cut off value between starboard tank and where the forward tank is tee'ed with the starboard tank. I leave the starboard tank turned off until the forward tank runs out then I CUT OFF the FORWARD tank and turn on the starboard tank - leaving them both on after the forward tank runs out doesn't work.
Here is a grid of what works - x is either on or off, bolded test is what I do:

Forward Starboard Results
Full/On Full/x Works
Full/On Empty/On Fills Starboard tank then stops working
Full/On Empty/Off Works
Empty/Off Full/On Works

Empty/On Full/Off Doesn't work
Empty/Off Empty/x Doesn't work
 
Feb 2, 2014
29
Catalina 30 mkII Pasadena, MD
I have the same setup on my 87 Catalina 30 MKII but I have a cut off value between starboard tank and where the forward tank is tee'ed with the starboard tank. I leave the starboard tank turned off until the forward tank runs out then I CUT OFF the FORWARD tank and turn on the starboard tank - leaving them both on after the forward tank runs out doesn't work.
Here is a grid of what works - x is either on or off, bolded test is what I do:

Forward Starboard Results
Full/On Full/x Works
Full/On Empty/On Fills Starboard tank then stops working
Full/On Empty/Off Works
Empty/Off Full/On Works

Empty/On Full/Off Doesn't work
Empty/Off Empty/x Doesn't work
Sorry the grid didn't work, the extra spaces disappeared. Read it as three columns, Forward, Starboard and the Results. The first row is Forward tank Full/On (tank full and turned on), Starboard tank Full/x (tank full and is turned on or off - the results are the same for either on or off) and Results are Works.
 
May 7, 2011
205
Catalina 30 Lake Lanier
I found the issue this weekend while at the boat. Someone had pulled so hard on the tube leading from the forward tank around a sharp corner that it was crimped HARD. Not sure why it stayed like that, but the hose is all sorta gummy now and was sticking to the fibreglass. I got it loose and removed the kink, water flows!

On our boat the forward tank does not flow directly into the strbd tank, but under it to a 'T' in the aft section under the quarter berth.
 
Oct 21, 2016
3
Catalina 30 MkII Harbor WA
I have the same setup on my 87 Catalina 30 MKII but I have a cut off value between starboard tank and where the forward tank is tee'ed with the starboard tank.
Mike, where is this cut-off valve and where the tee?
since we have the same year and model maybe mine has that too and im just not finding it?
Thanks,
tom
 
Feb 2, 2014
29
Catalina 30 mkII Pasadena, MD
Mike, where is this cut-off valve and where the tee?
since we have the same year and model maybe mine has that too and im just not finding it?
Thanks,
tom
If you take the cushion and cover off the battery compartment (aft of the starboard water tank) the hose from the starboard tank comes up between the tank and the batteries to a cut off valve which is just before the tee at the top outboard aft corner of the tank. The hose from the front water tank runs along the top outboard side of the starboard water tank to the top outboard aft corner of the tank to the tee. So looking at the tee, the front tank goes to the left port, the cut off valve for the starboard tank is on the bottom port and the hose to the water pump is attached to the right port.

It really seem weird to me that the tee was so high compared to the starboard water tank, at first I thought it wouldn't work so I was going to change it but I test it and it works fine so I left it as is. What we do before one of our week long cruises is fill both tanks and turn on the forward tank and turn off the starboard tank. When the front tank runs out we turn it off and turn on the starboard tank ... and get the holding tank pumped out (we stopped using sea water in our head and we don't drink the water in the tanks so most of the tank water goes in to the holding tank).
 
Oct 21, 2016
3
Catalina 30 MkII Harbor WA
If you take the cushion and cover off the battery compartment (aft of the starboard water tank) the hose from the starboard tank comes up between the tank and the batteries to a cut off valve which is just before the tee at the top outboard aft corner of the tank. The hose from the front water tank runs along the top outboard side of the starboard water tank to the top outboard aft corner of the tank to the tee. So looking at the tee, the front tank goes to the left port, the cut off valve for the starboard tank is on the bottom port and the hose to the water pump is attached to the right port.

It really seem weird to me that the tee was so high compared to the starboard water tank, at first I thought it wouldn't work so I was going to change it but I test it and it works fine so I left it as is. What we do before one of our week long cruises is fill both tanks and turn on the forward tank and turn off the starboard tank. When the front tank runs out we turn it off and turn on the starboard tank ... and get the holding tank pumped out (we stopped using sea water in our head and we don't drink the water in the tanks so most of the tank water goes in to the holding tank).

Well apparently they didn't build them all the same. My battery compartment is batteries only. The water tank compartment is only water tank with no valve or tee. Guess ill just have to keep investigating/exploring how mine was built. Hopefully I will find something somewhere that makes sense.
Thanks anyway for trying,
tom