Tapping the A/C raw water line for a washdown pump & spigot

[mobocracy]

I boat on a fresh water lake and would like a supply of pressurized water for hosing down the swim deck, the anchor or anything else that needs rinsing. I could use the existing fresh water spigot on the stern, but this just uses a bunch of fresh water I'd rather save for the head and galley and refilling is a nuisance.

The lake water is clean enough that it works well for this purpose. On my last boat I had a 12v portable pump, but its less convenient on a 310 DA.

Is there any reason I couldn't add a T fitting from the through-hull for the A/C water supply and plumb it to a washdown pump? I'm thinking I would either plumb it directly to the existing fresh water spigot and cap off the fresh water line at the manifold that leads to it or add a diverter valve so that I could gain fresh water from it if I wanted.

I'm assuming I'd want anti-siphon check valves to prevent backflow in any direction, preventing water from drawing or going in the wrong direction.

 

[insfnds]

Does your boat have a macerator and an overboard discharge for the head? If so, I'd use that through-hull (after disconnecting and capping off the macerator line,) as you can't discharge in a fresh water lake anyway.

AC water pumps lose prime very easily, so if you allow any air to back into the pump, your going to have to re-prime it. It is quite possible that the washdown pump will allow this to happen.

 

[JimFromMD]

I boat on a fresh water lake and would like a supply of pressurized water for hosing down the swim deck, the anchor or anything else that needs rinsing. I could use the existing fresh water spigot on the stern, but this just uses a bunch of fresh water I'd rather save for the head and galley and refilling is a nuisance.

The lake water is clean enough that it works well for this purpose. On my last boat I had a 12v portable pump, but its less convenient on a 310 DA.

Is there any reason I couldn't add a T fitting from the through-hull for the A/C water supply and plumb it to a washdown pump? I'm thinking I would either plumb it directly to the existing fresh water spigot and cap off the fresh water line at the manifold that leads to it or add a diverter valve so that I could gain fresh water from it if I wanted.

I'm assuming I'd want anti-siphon check valves to prevent backflow in any direction, preventing water from drawing or going in the wrong direction.

So I've been wanting to accomplish the same thing, but am in brackish water. My goal is to clean the anchor line/chain as it comes back on board. Originally I thought about tapping into the air conditioner cooling water line under the front bunk and then running it through the bulkhead into the anchor locker. Never got past the thinking stage. So you are looking to add /reuse your connection in the stern, then run a hose forward when you want to wash down?

 

[mobocracy]

Does your boat have a macerator and an overboard discharge for the head? If so, I'd use that through-hull (after disconnecting and capping off the macerator line,) as you can't discharge in a fresh water lake anyway.

AC water pumps lose prime very easily, so if you allow any air to back into the pump, your going to have to re-prime it. It is quite possible that the washdown pump will allow this to happen.

No macerator discharge on this boat, so no through-hull to tap into. My rough draft assumes adding check valves on both sides of the Y valve so that the washdown wouldn't suck water out of the A/C cooling line and vice versa.

So I've been wanting to accomplish the same thing, but am in brackish water. My goal is to clean the anchor line/chain as it comes back on board. Originally I thought about tapping into the air conditioner cooling water line under the front bunk and then running it through the bulkhead into the anchor locker. Never got past the thinking stage. So you are looking to add /reuse your connection in the stern, then run a hose forward when you want to wash down?

Yes. The water here is really clean and clear, so with a fine mesh strainer it works well for basic cleaning and doesn't leave any residue. I used a free-standing 12V setup on my last boat in this water without any problems.

While it would be nice to have a bow mounted washdown, that's a lot of complicated plumbing to get water up there. I'm willing to just run one of those self-expanding hoses from the transom spigot the few times I'd need it. So far, only one anchorage we use rarely has been a problem, too, and it was like 2 dunks to clear it. I might feel differently about a dedicated anchor washdown if it was bad every time.

If I can sort out the right fittings, this looks like a reasonable project. The most difficult items in my mind are finding the right fittings, the best place to mount the pump and if I can figure out how to wire it to one of the unused "accessory" switches on the dash (which I assume means finding the right EIM output).

 

[Stee6043]

I'd be willing to bet the "head" between your AC pump outlet (forward drain) and the "T" you would add will be lower than the head between the pump and the thru-hull in the water. As such you're simply going to suck air with your newly added pump after the initial blast of water (prime) you'd get from the water sitting in the system while at rest.

Unless of course you manually shut off the AC line preventing back-flow and forcing flow from the thru-hull? Though at that point you've lost all of the convenience factor I'd assume.

 

[cwiert]

I'd be willing to bet the "head" between your AC pump outlet (forward drain) and the "T" you would add will be lower than the head between the pump and the thru-hull in the water. As such you're simply going to suck air with your newly added pump after the initial blast of water (prime) you'd get from the water sitting in the system while at rest.

Unless of course you manually shut off the AC line preventing back-flow and forcing flow from the thru-hull? Though at that point you've lost all of the convenience factor I'd assume.

He said that he's going to add check valves at the new "Y" connector so that wouldn't happen.
However, I wouldn't want to accidentally turn the new hose on while the AC was running. If the new hose pump is stronger than the AC pump, you're going to "steal" the AC's water supply and possibly do damage to the unit.
If it were my boat, I'd simply use the water in the tank and replenish when needed. But your idea seems feasible, in theory.

 

[b_arrington]

Although drilling a hole in the bottom of my boat was one of the most nerve-wracking experiences, could you simply add an additional thru-hull for the washdown water intake. That would ease any issue with stealing water from the AC, or loosing price, or any of the other issues. I don't know if there is room for this, or if you can get the boat out of the water to do it.

 

[DougLas]

There are rules about macerates and dumping in the great lakes true. My thoughts here: What does the fishing boat charters do to get rid of their waste. Most charter boats I know of don't have a head. i can remember fishing with my father in law he used a bucket and just dumped it over board. Also where his cottage was there were alot of fishing boats and no pump outs.

 

[skibum]

I remember fishing with my uncle as a kid. Whenever I needed to go he would say, "Well... Get in the water and do your business and then get back in the boat...".

 

[mobocracy]

Although drilling a hole in the bottom of my boat was one of the most nerve-wracking experiences, could you simply add an additional thru-hull for the washdown water intake. That would ease any issue with stealing water from the AC, or loosing price, or any of the other issues. I don't know if there is room for this, or if you can get the boat out of the water to do it.

Yeah, an addition through hull makes sense. But it costs real money to get the boat hauled out and pay someone to put in the through hull and shutoff. Tapping the existing line and some basic plumbing is within my skill set and a lot cheaper.

As far as using both the wash down pump and the A/C at the same time, what's the max flow rate of the A/C through hull opening? A Shurflo washdown pump is 5 GPM, I don't know what the A/C pump is, but I'm curious -- with checkvalves to prevent reverse flow, does the through hull have enough volume to support A/C and washdown pump running simultaneously?

 

[Stee6043]

He said that he's going to add check valves at the new "Y" connector so that wouldn't happen.

Hmm...must have missed that part in the original post.

Either way I personally feel tossing an intake hose over the side of the boat is going to be a lot easier than the steps being discussed here. Shoot...mount a pump inside the transom locker and just have an intake hose you can pull out, throw in the water and carry on with washdown. Two seconds of effort each time you want to use it...

 

[JimFromMD]

As far as using both the wash down pump and the A/C at the same time, what's the max flow rate of the A/C through hull opening? A Shurflo washdown pump is 5 GPM, I don't know what the A/C pump is, but I'm curious.

Been Looking into this... My AC pump has a 3/4 inner diameter connections and max output of 500gph.

 

[JimFromMD]

I used a free-standing 12V setup on my last boat in this water without any problems.

A lot of the creeks around here are black mucky bottom made up of rotten leaves and stuff. Currently using a bucket on a string, but it'd be nice to be able to have a good flow of water to clean the anchor without killing the FW supply in my tank. What kind of free standing system did you use? I found one, but it looks like it puts out very little water in the demo video.

 

[mobocracy]

Been Looking into this... My AC pump has a 3/4 inner diameter connections and max output of 500gph.

At "average pressure" of 20-100 psi, most tables seem to indicate that a 3/4 ID pipe should be able to handle 23 gpm.

500 gph = 8.3 gpm, and the ShurFlo washdown pump is maximum 5 gpm, for a total of 13 gpm, about half the capacity of a 3/4 through-hull.

So it should be possible to draw from the same through-hull fitting for A/C and washdown simultaneously without compromising either too much.

A lot of the creeks around here are black mucky bottom made up of rotten leaves and stuff. Currently using a bucket on a string, but it'd be nice to be able to have a good flow of water to clean the anchor without killing the FW supply in my tank. What kind of free standing system did you use? I found one, but it looks like it puts out very little water in the demo video.

I used this TRAC washdown pump kit from Overton's.

http://www.overtons.com/modperl/product/details.cgi?pdesc=TRAC-Portable-Washdown-Pump-Kit&i=768382

I have to say, it worked pretty well. It's not power wash pressure, but I'd say it's 80% of the water pressure I get from my garden hose at home. Ideal for washing down bird crap and general lake flotsom that builds up on the swim deck.

I'd still be using it if it wasn't kind of annoying to use on my 310DA. The cigarette adapter power cord is only 6' and I can't find a great location to put the pump setup and still reach the helm 12V socket while simultaneously getting the feed hose in the water without the risk that I'm going dump the entire setup into the lake or the cockpit when I put tension on the hose.

That's what got me thinking it would be nice to have one permanently plumbed to the transom spigot.

 

[importmonkey]

What if you plumb the pump to the city water inlet of your boat? Drop the intake hose overboard, flip the switch, and use water wherever. Just have to "flush" all your lines when you get back to slip.

Sent from my SM-G930V using Tapatalk

 

[JimFromMD]

I used this TRAC washdown pump kit from Overton's.

http://www.overtons.com/modperl/product/details.cgi?pdesc=TRAC-Portable-Washdown-Pump-Kit&i=768382

I have to say, it worked pretty well. It's not power wash pressure, but I'd say it's 80% of the water pressure I get from my garden hose at home. Ideal for washing down bird crap and general lake flotsom that builds up on the swim deck.

I'd still be using it if it wasn't kind of annoying to use on my 310DA. The cigarette adapter power cord is only 6' and I can't find a great location to put the pump setup and still reach the helm 12V socket while simultaneously getting the feed hose in the water without the risk that I'm going dump the entire setup into the lake or the cockpit when I put tension on the hose.

That's what got me thinking it would be nice to have one permanently plumbed to the transom spigot.

That looks interesting. It shows the pump draws 14 Amps. Did you have any trouble running it off your cigarette lighter? Seems like a lot of current? Wonder what gauge wire SR used in the helm 12v socket.

One thought... I have a 12v "extension cord" to run some of my caframo fans in the cockpit. Maybe that's a solution to help using your current pump? I saw several lengths 5-25' extension through google search, but heres an example from amazon.
https://www.amazon.com/Victor-22-5-05103-8-12V-Extension-Cord/dp/B000BKJDKM

 

[mobocracy]

That looks interesting. It shows the pump draws 14 Amps. Did you have any trouble running it off your cigarette lighter? Seems like a lot of current? Wonder what gauge wire SR used in the helm 12v socket.

One thought... I have a 12v "extension cord" to run some of my caframo fans in the cockpit. Maybe that's a solution to help using your current pump? I saw several lengths 5-25' extension through google search, but heres an example from amazon.
https://www.amazon.com/Victor-22-5-05103-8-12V-Extension-Cord/dp/B000BKJDKM

On my old runabout, my #2 battery I kept in a trolling motor box with integrated cigarette lighter plugs and I plugged the pump directly into that. 14A seems high, if I remember right the cigarette plug for this pump has an integrated fuse holder with a 10A fuse. I'd guess you'd only hit 10A in a worst case scenario -- intake screen semi-plugged and long continuous run time when the motor got hot. The pump has a pressure switch just like a fresh water pump, so it only runs when you spray, then it cuts out.

Of course I immediately thought "extension cord" but 12V DC has so much voltage drop and increased resistance that it seems like it might be a problem for a pump.

And of course an integrated source of lake water with its own pump and spigot built-in seems so much more convenient.