Plumbing 2 Fresh Water Tanks

Sep 2, 2011
1,041
Hunter 27 Cherubini Alum Creek State Park
I have a flexible water tank up in the bow, under the v-berth, and I'm getting ready to add a rigid tank under the port settee.
What are some best practices for plumbing the new tank. I will be using Uniseals for the fittings.
Should I tee off the fill hose before the flex tank inlet, or go from the flex tank outlet to the new tank inlet?

The boat is a 81 Hunter 27
The fresh water fill is in the chain locker, 1-1/2" hose to flexible inlet
 
Jan 11, 2014
11,319
Sabre 362 113 Fair Haven, NY
It is probably best to have a manifold or Y-valve to select which tank is being used. This will allow you to leave the bow tank empty until you need it for a cruise and when one tank is empty there is another to switch to.

Why leave the bow tank empty? to keep weight out of the bow.
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
Are you planning to fill both tanks from 1 fill hose?

I have 2) 30 gallon tanks on my O’Day 322 (under both settees). They use separate fill hoses (1on each side deck).

The tanks are plumbed to a manifold where I can select port or starboard tank.

Greg
 

Bob J.

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Apr 14, 2009
773
Sabre 28 NH
I just added a tank under the port sette where a holding tank use to be. I connected the fills & vents from both tanks together. I isolated the supply with cheap ball valves so I could control which tank I draw from. I've got a couple pvc ball valves at home & plan on isolating the fills so I can chose which tank to fill.

Davids suggestion for a Y valve is good but compare the pricing using "cheap" pvc ball valves.
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
Apr 22, 2011
865
Hunter 27 Pecan Grove, Oriental, NC
My boat's water tank is fiberglass and is part of the hull. It's located on the port side under the v-berth. Is your rubber tank sitting in this fiberglass enclosure? If so, I wonder why the bladder was needed. Perhaps the lid was leaking??
 
Sep 2, 2011
1,041
Hunter 27 Cherubini Alum Creek State Park
My boat's water tank is fiberglass and is part of the hull. It's located on the port side under the v-berth. Is your rubber tank sitting in this fiberglass enclosure? If so, I wonder why the bladder was needed. Perhaps the lid was leaking??
The built in tank was so fouled that I could never get the bad taste out of it even using all of Peggie Hall's suggestions. So, now I just use it for the fresh water washdown pump.
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
I am not familiar with the flexible tank...will it properly fill and flow water through to the new tank?

If it collapses, blocks flow to the second tank, etc. it is going to be a real slow fill.
And if the flexible tank gets “skunky”, no way to fill the second tank unless you clean and fill the first tank.

A bit of extra work, but I sure like being able to fill and use my 2 tanks independently.

Greg
 
Sep 2, 2011
1,041
Hunter 27 Cherubini Alum Creek State Park
I am not familiar with the flexible tank...will it properly fill and flow water through to the new tank?

If it collapses, blocks flow to the second tank, etc. it is going to be a real slow fill.
And if the flexible tank gets “skunky”, no way to fill the second tank unless you clean and fill the first tank.

A bit of extra work, but I sure like being able to fill and use my 2 tanks independently.

Greg
I won't know the answer to the first question until I try.
That's a very valid point about the flexible tank getting fouled. Maybe a Y valve at the fill would be a good idea. I don't want to drill another hole in the deck for a 2nd fill tube.
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
The Apollo valves are bronze and may contain lead. The lead will leach out and, well, you don't wanna be drinking lead tainted water.
Ok. But the description says for water tank selection.

Greg