Tying the tanks together wouldn't allow you to isolate one if you had a leak or something. Doesn't sound like a good idea to me.
Bob Boyer S/V Rainy Days / Annapolis MD 1983 C&C Landfall 38 - Hull #230 email: dainyr...@icloud.com blog: dainyrays.blogspot.com "There is nothing--absolutely nothing--half so much worth doing as simply messing about in boats." --Kenneth Grahame > On Sep 10, 2015, at 12:31 PM, Josh Muckley via CnC-List > <cnc-list@cnc-list.com> wrote: > > So after some further investigation, all the tanks lead to a 4-way junction > below the floor board access at the bottom of the companionway stairs. There > are no valves or other separations between the three tanks. The 4th leg of > the junction goes to a valve and then to one of the galley sink "faucets". > > I still don't get it. I guess the PO had a use for it all. Here I was > thinking that there was a good engineering reason for tying the tanks > together. > > It's gone now. > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > >> On Sep 9, 2015 12:14 PM, "Josh Muckley" <muckl...@gmail.com> wrote: >> Rick, >> >> Thanks for the response. I guess I'm not communicating my setup very well. >> I have a standard deck fill dedicated for each tank. Each tank also has a >> vent which exits the hull of the boat below the respective deck fill. I >> also have an outlet which goes to a 4 valve manifold and then to the suction >> side of the fresh water pump. This way I can select which tank to use (take >> suction from). All of this seems pretty normal and makes plenty of sense. >> The last part is where the confusion begins. Each tank has a fitting near >> the top and a pipe that is the same size as the vent and outlet. All of the >> tanks are connected solely to one another via this fitting and pipe. Since >> the pipe is routed down and under it creates a u-bend or trap between the >> tanks. If the water level in a tank is less than the height of this cross >> connect fitting then water is not cross connected. If, on the other hand >> the tank is full then it will "overflow" through the cross connect u-bend to >> one of the other tanks. >> >> Josh >> >>> On Sep 9, 2015 11:01 AM, "Rick Brass via CnC-List" <cnc-list@cnc-list.com> >>> wrote: >>> As far as I can see, the only problem with not cross connecting the water >>> tanks would be the resulting complexity of your fresh water system and the >>> need to get access to all the valves every time you want to change tanks. >>> >>> >>> >>> You will need a line from each tank to the inlet of your fresh water >>> pressure pump, and to each of the foot pumps on your boat. In addition, you >>> would want to put a selector valve on the inlet of each pump – though I >>> suppose you could use the water shutoff valve at the outlet of each tank to >>> shut off the tank and isolate it from the rest of the water system. If you >>> don’t put in some sort of valve to stop flow from the tank you do not >>> intend to use to the pump, your tanks will still be cross connected; water >>> will flow from the tank which is more full to the tank with the lower water >>> level at through the connection just before the pump inlet. >>> >>> >>> >>> My 38 has 2 40 gallon tanks – one under each settee. There is a separate >>> fill and vent for each. There is a shutoff valve in the outlet for each. >>> Then water flows through a ½” hose to a “T” fitting under the cabin sole. >>> The other two ½” hoses go forward and back to the sinks. The hose to the >>> sink in the head forward goes to a foot pump. The line to the galley sink >>> is the supply to the fresh water pressure pump, and also to the foot pump. >>> >>> >>> >>> The cross connection is down in the bilge, so even when heeled with mostly >>> empty tanks the water in the tanks is above the suction line to the pump. >>> If you are using only one tank, that tank is mostly empty, and the boat is >>> heeled to that side, there is at least the possibility that there would not >>> be water flow to the inlet of the water pump. Drawing water from the low >>> side of the boat is not necessarily a bad thing. >>> >>> >>> >>> As far as filling all tanks from a single deck fill, the would be true in >>> theory. But the cross connect through a ½” hose like mine would take a long >>> time. The water into the deck fill through the garden hose would be a heck >>> of a lot more than the gravity fed ½” connection could carry. >>> >>> >>> >>> All that said, there are times when you might want to keep one tank dry. I >>> have 5 heavy batteries and a fair bit of added cabinetwork on the port side >>> of my boat. Hence the boat rests with about a 2 degree list to port. I hit >>> upon the idea of not using the port water tank the last time the tanks ran >>> down, and shut off the valve on the outlet of the tank. That way the weight >>> of the water in the starboard tank will offset some of the weight of the >>> stuff to port, which took care of most of the list, and having only 40 >>> gaallons of water is not much of a problem when not cruising. >>> >>> >>> >>> >>> >>> Rick Brass >>> >>> Washington, NC >>> >>> >>> >>> >>> >>> >>> >>> From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Josh >>> Muckley via CnC-List >>> Sent: Tuesday, September 08, 2015 2:55 PM >>> To: C&C List <cnc-list@cnc-list.com> >>> Cc: Josh Muckley <muckl...@gmail.com> >>> Subject: Stus-List Water tank x-connect >>> >>> >>> >>> So I'm doing some water tank work and I've confirmed what I already >>> suspected. My tanks are cross vented to one another through a low point >>> loop. It appears that I could in theory fill all my tanks from one deck >>> fill port despite having a fill port for each of my tanks. I'm thinking >>> that tracking tank level is a challenge when they are all sluicing between >>> one another. >>> >>> This doesn't seem advantageous. Why would the manufacturer do this. Is >>> there a problem with me undoing it? >>> >>> Josh Muckley >>> S/V Sea Hawk >>> 1989 C&C 37+ >>> Solomons, MD >>> >>> >>> _______________________________________________ >>> >>> Email address: >>> CnC-List@cnc-list.com >>> To change your list preferences, including unsubscribing -- go to the >>> bottom of page at: >>> http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >>> >>> > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the bottom > of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >
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