Redo of fresh water system

[AiniA]

This winter I will be reconfigurating the fresh waster system on my new (old) Nonsuch. I want a pressure pump, water heater, flow meter and filter. I assume that the pump should come first but what is the best sequence of the other bit - or does it matter?

[Bowdrie]

If you have the space, an accumulator tank in the circuit is a good idea.
Just using this as an example; https://www.groco.net/products/water...e-storage-tank
Also, a stand-alone pressure switch, (such as the commonly available ones from "Square D," work much better than the switches built into most pumps, as then you can adjust both the cut-in and cut-out pressures to suit your needs.
Order of work?,, probably defining the locations/orientations of the components so that access is reasonably achieved.

[Tetepare]

Assuming you already have most of those key components, don’t rip it all out. Replace one at a time. It’s like taping before painting- the prep sucks, but ultimately you will save time.

In matter of priority, replace what’s busted first. Then biggest item to smallest.

Do replace the piping, later if you can. When you do, toss the old hose clamps, even if they seem fine.

[AiniA]

The tanks and faucets are fine but need everything else. The boat does not have pressure water or a heater. This is a once every 44 year refit of the boat.

[tkeithlu]

OK. 30' boat, so one head, one shower, one water heater, one tank, and one pump. A 2 or 3 gallon per minute automatic pressure pump, such as a Jabsco will do:

https://www.amazon.com/Jabsco-31395-...rpt=WATER_PUMP

Consider adding a sight gauge or some other way to tell how much water you have - I do it by making the fill pipe clear vinyl, so I can see the water level in the tank. Simple, it works.

Consider piping the whole thing in PEX or CPVC. PEX is more flexible, CPVC is cheaper. Avoid rubber hose.

A six gallon hot water heater will cover the needs of a couple for daily showers as long as no one goes Hollywood.

That's really all you need. You've got a simple system. I added recirculation of hot water so we don't run the water to get to the hot, but you have short runs and if you use 1/2 inch pipe you won't lose much.

You'll be able to detect a leak by the pump cycling as pressure drops. You get a better read on that if you don't have an accumulator, because there's no stored pressure other than the very slight bulging of the CPVC.

I don't think that a flow meter is going to add enough information to be worthwhile. You'll know fast versus slow flow from the sound of the pump, and total use by looking at the sight gauge. Calibrate it by filling the tank from a five gallon can if you want to know more.

Good luck with it. Running the CPVC or PEX through an old boat may teach you why sailors are known for their salty language.

[tkeithlu]

That fill pipe. I made a T junction for it between the exit to the tank and the pump, so water enters the tank at the bottom. Then I sized down the exit pipe before it reaches the pump. One sight gauge.

[AiniA]

The flow meter I am thinking about records the total amount of water used since being reset so it is sort of an inverse tank monitor. It is a gardening item so not marine price (~$30).