Fresh water plumbing from scratch. How would you do it?

[GILow]

Hi all,

I had the chance to start from scratch with my fresh water plumbing.

The boat is a 42 foot monohull, and I have built two water tanks, against the hull to port and starboard, each around 350 litres (around 90 gallons) plus a staging tank on the port side of around 50 litres (13 gallons).

The logic behind this was to allow me to keep the boat in trim by having fresh water on both sides (it was all on the port side originally) and the staging tank is for the watermaker (Pursurvivor 35) and rainwater collection, to be tested before transferring to the main tanks.

I am starting from scratch, there is no existing pipe work in the boat. I have two decent quality fresh water pumps, but both are pretty old.

I am good at automation so I am happy to dabble with electronics to manage distribution, consumption and balancing.

Finally, I will be a solo-live-aboard, at anchor, not marinas, so the boat will have to create/collect all her own fresh water, but consumption will be light.

So, how would you plumb all this together?

Matt

[Psy at SEA]

Matt, my Roberts is plumbed (both fuel and H20) with hard copper and conex fittings.
Jabsco pumps etc are all plumbed with clear woven pvc piping and hose clamps.....which is crap imho.
I intend to redo the plumbing from the pumps with PEX fittings and piping to filters and taps/showers/basins.
I believe the PEX to be far superior to the hose clamp story.
Its work in progress...I inherited the boat as is.

[El Pinguino]

I have port and starboard water tanks under the saloon setees... 200 litres each.
Both drain into a sump tank midships under the sole.... maybe 20 litres.
Port tank can be isolated... I normally run on one tank on passage... that way you know when you have used half your water.....
Yes... you do end up with all your water on one side....
No.... it doesn't cause a noticable list...
But... if they aren't isolated it will all gravitate to the low side when going to windward...

To the pressure pump it is just that woven hose with hose clamps... it is some fancy plastic pipe (PE? .. as built... brown in colour...) on the delivery side.

Don't ask how its plumbed in ... long time since I worked on it.... I have both an electric pressure pump in the 'garden shed' and a whale foot pump in the galley so that if electric is turned off I can use the foot pump..... saves bucketloads of water on passage........

Sister ship info here with a PDF of what he has done... mine is 'as built' ... https://yachtcamomile.co.uk/?s=hose+system

[El Pinguino]

An idea of how my foot pump is plumbed in ... from that PDF... but mine works on both hot and cold in the galley... not just a dedicated drink water tap.....

[Tillsbury]

I would steer well clear of automation, personally. I have two tanks (and have on previous boats), and on more than one occasion something or some connection has crapped out and pumped the entire tank into either the bilge or outside. It's very reassuring to know that the "other" half of your water supply is completely safe from being pumped out.

Added to which, transferring from one tank to another is your way of knowing that you're half-way through your water supply (if your watermaker was to die, for example).

Also, I agree with the poster above that 200kg excess on one side or the other of the lower hull is way less than having a single 100kg person sitting on the rail. Seriously, is that going to make any useful difference for a cruiser?

[s/v Jedi]

I recommend the 15mm Seatech PEX and fittings. Also, a manifold with valves connecting both tanks with the pump. I use two pumps, i.e I installed the spare pump.

For the lines from tanks to manifold I use 3/4” PEX with Sharkbite quick fittings. From the manifold to the pumps I use flexible stainless steel connectors at 1/2” diameter.

The manifold has a cross connect valve to allow each pump to draw from each tank in case of a pump failure but want to draw from the tank normally used by the failed pump.

[GILow]

Wow, I’d given up on getting a response to this question. Thank you PSY for waking it from the dead.

Some great ideas here. Had not thought of using PEX for a start.

I will see how the various suggestions map to my setup options.

[Mr. Matt]

How have the sharkbite quick fittings held up in the marine environment? I have wondered if they are suitable for use on a fresh water system.

[rbk]

I also worry about the shark bite fittings but failures are rare. More concerning is the failure rate of pex fittings primarily their T’s in land based residential applications. There was a lawsuit a few years back which supposedly cleared up the issues (cheap alloy’s) but I’ve had 8 failures in the last year on 2 builds causing significant damage.

[capn_billl]

Both boats I've owned used cheap plastic compression fittings with flexible polyurethane tubing, (fiber reinforced for hot).

Both PEX, and sharkbite are a big improvement. I've been replacing fittings with sharkbite as they fail, as I just can't find the poly (I believe they are Parker), fittings.

[Psy at SEA]

GI...

Way back yonder I used to install Beer dispensing equipment for a Micro Brewery, using PEX and quick/snap fittings similar to the seatech quick release fittings.
No leakage, no breakage, and easily pulled apart for maintenance or complete removal, easy to install.

The seatech kit looks the real deal, im sure improved design etc...look at rated psi/bar figures. (150psi/10bar)

Agree with Jedi Capt. ~ my boats tanks have a pressure line as well as a foot/manual pump suction line with individual shut off valves installed. important to mount all valves and route piping through fixed saddles on good foundations to prevent any movement, thus preventing leakage etc.

Label and build a drawing of your system as you go.

Tank tender system monitors water levels, or visual check via clear top see thru covers.



Sea Tech, Inc - Leading Manufacturer of Quick Connect Fittings, Quick Connect Manifolds and Valves, PEX Tubing

[ranger58sb]

Red and blue PEX (colors mostly for future troubleshooting) and decent fittings. As far as I know, Sharkbite are OK...

Pumps, strainers, accumulators, etc. connected with QEST quick-connect fittings.

-Chris

[FAST FRED]

I would only choose std copper tubing with flair fittings.


My main concern is copper is toxic to much green slime that can grow in in other style piping.Available world wide and spare can be onboard for "ever" and still be fine.



If you select a DC water pump with an adjustable output pressure , use 1/2 inch tubing and 15 or 20 psi of water pressure will do showers etc. at 1/2 the electric cost.

[FAST FRED]

I would select only soft copper tubing and flair fittings.

My main concern is copper is toxic to much green slime that can grow in in other style piping,and seldom used tanks. Available world wide and spare can be onboard for "ever" and still be fine.

If you select a DC water pump with an adjustable output pressure , use 1/2 inch tubing and 15 or 20 psi of water pressure will do showers etc. at 1/2 the electric cost.

[capn_billl]

How is an o ring allowing salt water into fresh?