Selectable Washdown Setup (Fresh/Raw water)

[ErBrown]

Howdy Folks,

We've now been cruising the east coast (US) for the past 6 months Texas to Long Island Sound and back to FL. We're now prepping to hop over to the Bahamas in the next couple moths. As you can imaging, we've learned a ton in the last 6 months and part of that is that we don't do many marinas, preferring to anchor out almost exclusively. It works for us, but one of the challenges we've faced as a result is difficulty with keeping the boat clean outside.

Many times after a hop, we have a very salty boat and no easy way to rinse with fresh water. We do have a washdown setup at the bow, but it's currently raw water only. Until recently this was our only reasonable option since we've been relying primarily on totting jerry cans, to replenish our fresh water.

We've recently added a water maker and while we still intent to be relatively miserly with our fresh water, we'd like to add a fresh water option to this setup. I'm curious what others have done here. Is it feasible to add a Y-valve to the intake side of the pump? Allowing us to select raw water from the dedicated thru-hull or diverting the intake to the fresh water tanks? Or is the only realistic option dual pumps?

Also, when tapping into the fresh water pick-up, do we need to do anything special to prevent water from draining back through the pump into the tank?

Apologies in advance if this is super basic, but want to be sure I'm thinking this through...before buying parts.

Thanks,
Erin

[boatman12]

The most important consideration is preventing contamination of the fresh water supply with salt water. In theory, a check valve would do this but I would be looking for something a little more reliable.

[sailorchic34]

Originally Posted by ErBrown

Is it feasible to add a Y-valve to the intake side of the pump? Allowing us to select raw water from the dedicated thru-hull or diverting the intake to the fresh water tanks? Or is the only realistic option dual pumps?

Also, when tapping into the fresh water pick-up, do we need to do anything special to prevent water from draining back through the pump into the tank?

This is a bit complicated. You are correct that you do not want to mix salt water and the the critters in it with your fresh water tank.

There are reduced pressure backflow preventers that are designed to prevent backflow into potable water systems. They are designed for situations just like this. A watts U009 for example would work. BUT they have a 13 psig pressure drop across them and that may be too much pressure drop on the suction side of the pump. It might work or it might not.

Really the safest and least expensive thing perhaps would be to add a second fresh water hose bibb with an installed vacuum breaker on deck. That prevents a cross connection between salt water and the fresh water tank. The vacuum breaker gives enough protection to prevent baackflow into the fresh water system.

[ErBrown]

Originally Posted by sailorchic34

Really the safest and least expensive thing perhaps would be to add a second fresh water hose bibb with an installed vacuum breaker on deck. That prevents a cross connection between salt water and the fresh water tank. The vacuum breaker gives enough protection to prevent backflow into the fresh water system.

This makes sense, and was my largest concern. Obviously we don't want to compromise drinking water for a convenience feature. That being said, I'm really not to excited about the idea of cutting another hole in the deck for a fresh water wash down.

Will have to see what else we can come up with.

[Pelagic]

Do you already have a fresh water pump for showering and galley duty?

If YES.....The easiest solution is to run an extra fresh water spur to the stern with a quick connect for a hose or cold water shower.

Odds are you have a small Jabsco Par pump for your FW needs....If you find it is a bit weak for hose pressure, then buy the next size up and keep original as spare.

Also now that you are making water, consider a FW line for flushing toilet.....makes a huge difference in smell and contaminated line issues.

Will never go back to salt water flush, except in emergency

[DeepCut]

Interested in your solution as I am adding a water maker as well as fresh water for deck wash down. I am anticipating it being in aft area. Also suggested by a (fisherman)friend is a raw water wash down. I would think you would not need raw(salt) water wash down if you have a water maker with sufficient capacity(what model did you add?) and thus nearly unlimited fresh water .

[wrwakefield]

Hi Erin,

Assuming you have pressure fresh water in addition to your pressure raw water [i.e., 2 independent pumps and systems...] you may want to consider a 3-way ['Y'] valve on your washdown feed line. Use that valve to select fresh or raw water to feed your washdown. Simple, and it keeps your water systems separate. [i.e., Reduced chances of cross-contamination...]

This is how we set up our boat. It allows us to wash a dirty anchor chain with raw water as it is raised, and rinse with fresh once in the locker to help prolong chain life.

Be sure to use a 3-way valve that is compatible with raw [salt] water... i.e., plastic, stainless steel, or bronze. [no brass...]

In case this is helpful.

Cheers! Bill

[kenbo]

Originally Posted by wrwakefield

Hi Erin,

Assuming you have pressure fresh water in addition to your pressure raw water [i.e., 2 independent pumps and systems...] you may want to consider a 3-way ['Y'] valve on your washdown feed line. Use that valve to select fresh or raw water to feed your washdown. Simple, and it keeps your water systems separate. [i.e., Reduced chances of cross-contamination...]

This is how we set up our boat. It allows us to wash a dirty anchor chain with raw water as it is raised, and rinse with fresh once in the locker to help prolong chain life.

Be sure to use a 3-way valve that is compatible with raw [salt] water... i.e., plastic, stainless steel, or bronze. [no brass...]

In case this is helpful.

Cheers! Bill

If you follow this path try to keep the outlet hose from the 3 way valve as short as possible and install a quality bronze check valve immediately after the 3 way valve outlet. Still not fool proof but better.

[Cheechako]

I considered this also. In the end I figured it was much better to have a dedicated outlet or pump for fresh water. That extra pump could be your FW pump spare also!
BTW, a stern shower handle is very nice further south, this could be setup as your washdown also!

[NahanniV]

Originally Posted by wrwakefield

Hi Erin,

Assuming you have pressure fresh water in addition to your pressure raw water [i.e., 2 independent pumps and systems...] you may want to consider a 3-way ['Y'] valve on your washdown feed line. Use that valve to select fresh or raw water to feed your washdown. Simple, and it keeps your water systems separate. [i.e., Reduced chances of cross-contamination...]

This is how we set up our boat. It allows us to wash a dirty anchor chain with raw water as it is raised, and rinse with fresh once in the locker to help prolong chain life.

Be sure to use a 3-way valve that is compatible with raw [salt] water... i.e., plastic, stainless steel, or bronze. [no brass...]

In case this is helpful.

Cheers! Bill

Even with the suggested check valve, this will allow a bit of raw water to mix with the fresh water each time it is switched.
If you drink the water from your tanks, I don't think it's a good idea.

[Cheechako]

Even simpler than my other suggestion, it's easy to just T in to your fresh water hose at any location and add a washdown spigot where you want it. The anchor locker is a great place as you can wash heavy mud and goo off your anchor and chain as it comes up.

[stormalong]

I do not think you realize how quickly you will deplete your water maker water by rinsing your deck with it. The energy and time needed to produce RO water makes it very expensive. Are you sure you really want to do this?

[Oceanride007]

I invested in some irrigation fittings, can now use the deck hose via the fresh water system, easy with quick connect fittings (We call them Gardena in Aus).

[sailor1924]

We've got both: a dedicated salt water pump and washdown midships and a fresh water spigot in the stern plumbed into the fresh water system. We also have a small 110 volt pressure washer that we use as a fresh rinser. We don 't have a water maker.
The pressure washer allows a very low quantity effective rinse down after using the salt walt pump for various kinds of cleanup. We can flush wash with the salt water, and then can rinse off the salt residue using only a few gallons of fresh water. We carry 185 gallons of water which usually lasts 10 days to two weeks. If I'm really concerned about rationing water I can use a 5 gallon bucket as feed water for the pressure washer and be sure exactly how much water I use for the rinse.

[Cheechako]

In the anchor locker: