Watermaker install questions

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rtjohnso
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Watermaker install questions

Postby rtjohnso » Mon Mar 21, 2016 12:08 pm

I'm looking to install a Schenker watermaker on my 2000 PDQ 36. The pump for the watermaker needs to be below the waterline. Everything else can be above.

I will also be installing a freshwater head, so the head intake thruhull will be available and is of the right size, so I'd like to use that as the watermaker intake, if possible.

The main concern I have is finding a way to mount the pump so that it will be reliably below the waterline.

Can anyone comment on the following installation ideas:

Option 1. Put the pump as low as possible in the lazarette abaft the shower. Run the intake hose from the seacock through the bulkead. This is my preferred solution, if it will work. I can put the watermaker in the starboard aft lazarette under the bench. Hose runs are short (except from the watermaker to the tank). Freshwater is already available in the pump lazarette for the watermaker's rinse cycle. Plenty of room for installing and accessing filters. Electrical wire conduits are available. Salt discharge just goes through a scupper. A leaky high-pressure hose won't sink the boat.

Option 2. Put the pump in one of the forward closets (where instrument transducers usually go). Probably in the port hull. Maybe re-use an instrument thruhull. In this case, the watermaker would go under one of the settees in the saloon. The main challenge here is running hoses and wires to/from the pump. Can I run them through the bilge? Is there access for them to go from the bilge up to the space underneath the settee? Is there another route that makes more sense?

Option 3. Put the pump underneath the floor in one of the hull hallways. This would probably require a new thruhull, also under the floor. The main problem I see is that, underneath the wood floor in the hallways is a solid sheet of fiberglass, which does not afford access to the actuall hull. Is it safe to cut an opening in this sheet of fiberglass in order to gain access to the hull? Is it structural, or are there stringers underneath to hold the hull in shape?

Or if anyone has a better idea, I'd love to hear it!

Thanks for any help you can offer.

Best,
Rob

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chicagocat
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Re: Watermaker install questions

Postby chicagocat » Mon Mar 21, 2016 3:25 pm

Those are all interesting ideas.

I have a Spectra 150 under the starboard setee in the saloon of Cat Tales. The raw water intake is aft of the shower in the starboard lazarette. I don't know the Schenker units, but the Smart series on the web site looks very much like a Spectra. However, the Spectra does not require the pump to be under the waterline, so mine is under the setee.

Given that you need the pump under the waterline, I guess that option 1 seems best. I think that option 2 (pump under forward clothing closet) will mean that the pump is more often above the waterline, with boat wakes, etc.

Also, my Spectra isn't exactly silent. It would be kind of nice if it were outside in the cockpit. Of course, you have to take into account the exposure to the elements. Even just hosing down the cockpit can get water in that starboard aft compartment if the drain isn't perfectly clear. So you want the pump in a place where it hopefully won't be exposed to a lot of water.

Finally, regarding option 2: yes, you can get hoses etc. from the starboard cabin bilge to the main cabin setee. Just take out the "shoe rack" that is on the side of the bed and you'll see how you can run them. That's how the air conditioning on Anne Z is run.
PDQ 36052 - 1996 LRC - "Anne Z" - Chicago
and 2001 PDQ 36 Classic (Tall Rig)- "Cat Tales" - Punta Gorda, FL

duetto
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Re: Watermaker install questions

Postby duetto » Tue Mar 22, 2016 10:00 am

hi,

we use an a/c pump for rw on our 34 powercat. it's mounted in the bilge forward. whe we first installed it periodically would not pump. turned out that with waves the bow was coming out of the water and air would get trapped in the hose and prevent pump priming. installing a check valve solved the problem.
john & diane cummings
duetto mv34 #23

krakato
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Re: Watermaker install questions

Postby krakato » Wed Mar 23, 2016 10:39 am

Rob,

I'm getting ready to install a Spectra 150 on my 1998 36. I also looked at all the options you have outlined and chose your option #1. Plenty of room in there to work on things as well.

I know several have put it under the starboard settee, but that is where our air conditioner sits so that is out for us.

Cheers,
Mike
--------------------------------------------
Krakato: 1998 PDQ 36 Capella Classic
Hull #67
http://krakato.net

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chicagocat
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Re: Watermaker install questions

Postby chicagocat » Wed Mar 23, 2016 11:03 am

Hi Mike,
I'm a little confused about your plan. You said you can't put the Spectra under the starboard setee, but you said you were following Robs option 1, which is to put the pump near the holding tank but the watermaker under the starboard setee. Maybe you meant you're putting the whole thing in the aft outside locker?

Just curious...
Also, if you have questions about the Spectra 150, I've been through mine pretty thoroughly over the last fews years, so give me a shout.

Brendan
PDQ 36052 - 1996 LRC - "Anne Z" - Chicago
and 2001 PDQ 36 Classic (Tall Rig)- "Cat Tales" - Punta Gorda, FL

rtjohnso
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Re: Watermaker install questions

Postby rtjohnso » Wed Mar 23, 2016 10:42 pm

First, thanks to everyone for the helpful replies!

It sounds more and more like option 1 is feasible. I'll go to the boat and measure whether the bottom of the lazarette behind the shower (where the propane instant hot-water heater is on my boat) is below the waterline. I'll report back.

To clarify, the watermaker itself (i.e. the membrane) would go in the long lazarette under the bench at the back of the boat, i.e. where the davits are.

Also, if anyone else is in the market for a watermaker, check out the Schenkers. They seem even more efficient than the Spectra's, have generally good comments online, and cost half as much. Of course, I don't own one yet, so maybe I'll have a very different opinion two months from now...

Best,
Rob

krakato
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Re: Watermaker install questions

Postby krakato » Mon Mar 28, 2016 3:55 pm

chicagocat wrote:Hi Mike,
I'm a little confused about your plan. You said you can't put the Spectra under the starboard setee, but you said you were following Robs option 1, which is to put the pump near the holding tank but the watermaker under the starboard setee. Maybe you meant you're putting the whole thing in the aft outside locker?

Just curious...
Also, if you have questions about the Spectra 150, I've been through mine pretty thoroughly over the last fews years, so give me a shout.

Brendan


Brendan,

You are correct. I'm putting the whole thing in the outside locker. (Guess I was the one confused! :lol: ). It will be a few months before I install ours (one of the last tasks before heading out for the islands). But if I run into problems, I'll be in touch!

Cheers,
Mike
--------------------------------------------
Krakato: 1998 PDQ 36 Capella Classic
Hull #67
http://krakato.net


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