Install holding tank in 79 MK1

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Capt Carl

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Joined
Sep 17, 2020
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Location
USA
I have seen conversions on the 79MK1 wherein
a holding tank was installed under the deck in the Galley just outside of the door to the head. I would like to update the head with a new toilet and connect it to a holding tank for additional capacity. I believe the conversion I have seen was on a 79MK1 from the Chesapeake Mainship Group, although not sure. I would appreciate any information concerning this conversion; plans, pictures, costs, degree of difficulty of installation, etc. Thank you for your help!
 
There really isn’t a lot of room unless you mean in the closet area forward of the head. We ended up going the Pursan route to eliminate the holding tank altogether. Can you post if pic of where you want to mount one?
 
I've seen the use of that space for a holding tank, adjacent to the head in the companionway. Maybe David Kimmel on here will chime in with pictures of his because he has a holding tank in that area. It's a good use of wasted space and way better than the pitiful 9 gallon tank we have intergraded into/underneath the Dometic head we have, though we make out ok with it.
There's so much underutilized space on those 34's. I hope to get the gumption this off-season to use that space & build a shelf for storage of non perishables like drinking water ,wine & whiskey. Basic essentials. ;)
 
The original head was in need of repair plus the holding tank under the head wasn't enough for our needs so we decided on a Raritan Elegance head replacement that required a holding tank. I chose to place 25 gallon tank between the galley and head after getting the dimensions from the Yahoo Mainship forum( i'll see if the info is still available).
The cut out dimensions opened the area between the aft bulkhead about 18" forward of the shower sump and the foward bulkhead before the V berth section. Our salon sole is teak/holly and the galley floor was covered with carpet. The same teak/holly pattern was not available so I used teak faced plywood for the floor, holding tank and shower sump hatch.
Installing the discharge hose from the head and the hose to the pump out deck fitting required opening the shower sump bulk head to allow them to pass thru.
I have since seen a tank installed by cutting a approx 6" notch out the two bulkheads mentioned and placing a longer smaller tank on top which doesn't require building a support shelf to hold the tank.
My dear wife would tell you this was the best upgrade we have made.I would agree for the most part BUT the installation of the autopilot by BOOERANG ranks high on the list. I love it!! Capt Carl BTW I nosed around and found the dimensions on Yahoo.
Good Luck.
 

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... way better than the pitiful 9 gallon tank we have intergraded into/underneath the Dometic head we have, though we make out ok with it...

If you're referring to this system SeaLand Traveler at Defender it's really just a glorified MSD portapotty, but SeaLand did such a great job of glorifying it that it's one of my favorite systems for several reasons: 1. It's self-contained, eliminating a bunch of plumbing and all the related problems that go with it, which makes it a great choice on boats that don't have a good location for a tank...2. It has a china bowl that's pedal operated like the VacuFlush--step on it to flush, stick your toe under it to lift it to bring in flush water ahead of solids. 3. Unlike the VacuFlush, it actually can use as little as 1 pint of flush water--just enough to rinse the bowl, allowing that "pitiful 9 gallon tank" to hold at least 75 flushes...you'd need about a 40 gal tank to hold that many from any other marine toilet. If you're filling it up much faster than that you're using waaay too much flush water. You shouldn't need to add any water to the bowl ahead of urine only, and only about a quart ahead of solids.



--Peggie
 
If you're referring to this system SeaLand Traveler at Defender it's really just a glorified MSD portapotty, but SeaLand did such a great job of glorifying it that it's one of my favorite systems for several reasons .... it actually can use as little as 1 pint of flush water--just enough to rinse the bowl, allowing that "pitiful 9 gallon tank" to hold at least 75 flushes...

I agree! I'd always had "boat systems" on sailboats (they worked fine but there is a fair bit to them), and when I got my first RV and realized how the toilet worked, I almost had to laugh. Basically a glorified outhouse (mine uses a 15-gallon tank underneath the RV, but it's the exact same "straight down the hole" as the one we are referring to here).

And I don't mean that in a bad way, as up north I've used some great outhouses. But it's just that I was expecting more "opacity" and complication to the system. Pleasantly surprised at how simple it was.

But what really endeared it to me is that - as you say - it makes the tank last SO MUCH longer. I was thinking the 15-gallon black tank was going to be really meager (was used to typical boat systems), but it's simply amazing how long it lasts when you don't have to clear numerous long or convoluted pipes or hoses when you flush.

Just let what you've just "put" into the bowl drop straight down the hole, and then use a little water to essentially clean the bowl (and then a small amount of additional water in the bowl makes the "trap" in the bowl to keep smells below).

Were I to find a boat that had the space right in the head to use this 9-gallon system, I would be pleased. Granted, if I could fit a huge black tank elsewhere that would be great; but boats with this system aren't usually of a size to do that.
 
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... way better than the pitiful 9 gallon tank we have intergraded into/underneath the Dometic head we have, though we make out ok with it...

If you're referring to this system SeaLand Traveler at Defender it's really just a glorified MSD portapotty, but SeaLand did such a great job of glorifying it that it's one of my favorite systems for several reasons: 1. It's self-contained, eliminating a bunch of plumbing and all the related problems that go with it, which makes it a great choice on boats that don't have a good location for a tank...2. It has a china bowl that's pedal operated like the VacuFlush--step on it to flush, stick your toe under it to lift it to bring in flush water ahead of solids. 3. Unlike the VacuFlush, it actually can use as little as 1 pint of flush water--just enough to rinse the bowl, allowing that "pitiful 9 gallon tank" to hold at least 75 flushes...you'd need about a 40 gal tank to hold that many from any other marine toilet. If you're filling it up much faster than that you're using waaay too much flush water. You shouldn't need to add any water to the bowl ahead of urine only, and only about a quart ahead of solids.



--Peggie

Peggie, you're right about it overcoming it's reduced capacity by using less water per flush. Honestly we've never actually had an issue of it being too full between pumpouts, come to think of it.
But, and it's a big but, each flush opens a 4" hole straight into the self-contained holding tank, allowing a big ol' whiff of stink to come out, which is doubly pungent in warm weather &/or when it's been a few days without a pumpout. It's not the most pleasant thing to have an invisible cloud of gas lingering in the head & galley area which is adjacent to the head in our boat. When it's just my wife and me onboard it's one thing but when we're entertaining ,it's downright embarrassing. Like I said in my previous post, it suits us fine & it's very doubtful I'll ever change it out to a regular head with a holding tank but the thing seems a bit rinky-dink to be used on a real yacht, for sure!
 
We bought a Carver that had a Traveler head in it. My wife flushed it once and said get rid of it due to the open holding tank.
 
But, and it's a big but, each flush opens a 4" hole straight into the self-contained holding tank, allowing a big ol' whiff of stink to come out, which is doubly pungent in warm weather &/or when it's been a few days without a pumpout.

An easy problem to solve: replace the vent thru-hull with an open bulkhead thru-hull that permits the air exchange needed to prevent odor in the tank and switch to a tank product that actually works. NoFlex Digestor is the one I recommend.


We bought a Carver that had a Traveler head in it. My wife flushed it once and said get rid of it due to the open holding tank.


A good thing she wasn't exposed to any of your shortcomings on the first date!


--Peggie
 
We bought a Carver that had a Traveler head in it. My wife flushed it once and said get rid of it due to the open holding tank.


A good thing she wasn't exposed to any of your shortcomings on the first date!


--Peggie[/QUOTE]

Peggie,

Actually she asked me out on our first date. We were in high school then and worked together on the yearbook. Last month we had our 49th anniversary. She has had a good deal for so long that I think she has forgotten my faults from back then, and BTW I keep reminding her that she has had a good deal...
 
I also (this is in an RV) make sure to not have any vents actively pulling air out (because that will suck air "in" from the toilet when you open the flap). That may not be quite as easy on a boat (in an RV there is often a roof vent with a fan in the bathroom; pity the person who flushes the toilet with that fan set to exhaust at the moment of flushing, which creates negative pressure in the toilet room).
 
But, and it's a big but, each flush opens a 4" hole straight into the self-contained holding tank, allowing a big ol' whiff of stink to come out, which is doubly pungent in warm weather &/or when it's been a few days without a pumpout. It's not the most pleasant thing to have an invisible cloud of gas lingering in the head & galley area which is adjacent to the head in our boat. When it's just my wife and me onboard it's one thing but when we're entertaining ,it's downright embarrassing.


But, and it's a big but, each flush opens a 4" hole straight into the self-contained holding tank, allowing a big ol' whiff of stink to come out, which is doubly pungent in warm weather &/or when it's been a few days without a pumpout.

An easy problem to solve: replace the vent thru-hull with an open bulkhead thru-hull that permits the air exchange needed to prevent odor in the tank and switch to a tank product that actually works. NoFlex Digestor is the one I recommend.


We always used Peggie's KO back when we had our Mainship with the Traveler head...

We had no particular odor to worry about. And that's without any messing about with the vent.

-Chris
 
K.O. which stands for "Kills Odor," is a live bacteria holding tank product that the company I owned introduced in 1987 and which became part of the product line I sold to Raritan in 1999. It was the first tank product that applied the laws of basic bio-physics to PREVENT odor from occurring instead of trying (mostly unsuccessfully) to suppress it after it's created using toxic chemicals.

--Peggie
 
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peggy noflex or k.o.

Peggy, Interesting history concerning K.O. I read" An easy problem to solve: replace the vent thru-hull with an open bulkhead thru-hull that permits the air exchange needed to prevent odor in the tank and switch to a tank product that actually works. NoFlex Digestor is the one I recommend."..
I got to ask this question. .What are the differences between K.O. and Noflex Digester?
I'm "overboard" sometime with the dosage and get no odor. I don't combine products, only observations of different years using either K.O. or Noflex.
 
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