Holding tanks

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Added 02/25/2004

I know this question goes around every couple of months. Does anyone remember the holding tank website that was being passed around? and
secondly has anyone ever refit a C26 MKII with a holding tank?

Mines a 1969 version with two water tanks. There is a spot on the port side
of the V-berth that looks like it might hold a small tank. Any suggestions?

Jim Danielson
"Kelly Ann"
Narragansett Bay, RI


Jim, the heads on our boats should be identical.  I am presently in the
process of replacing a porta-pottie (that replaced the original head) with a
Raritan PHII and a Raritan Compact rigid holding tank that wraps around the
aft side and front of the head fixture.  If my measurements are correct, it
is going to be an extremely tight fit fore/aft.  I may need to relieve the
aft side of the basin glasswork to fit the pump assembly.  I am planning to
use the custom fitted platform for the porta-pottie to support the

I plan to feed the head from a flexible 13 gallon tank in the port side
v-berth well.  The starboard well holds a 26 gallon flexible tank for the
water system to the sinks.  The original water tank under the dinette seat
has been converted to storage with a hinged lid.

Hope this helps.

Dan Johnson
1972 Coronado 27 #316
On the hard in North East, MD



I was looking at putting the holding tank under the dinette seat on the port
side next to the head bulkhead.  I was not sure how to run the deck mounted  service port.  Then, I was going to move the water tank to the bottom of the hanging locker on the starboard side.

Both tanks would be amidship, and there would be a little more balance. 
Currently, water and batteries are on the port, and I think I list a little to
that side.

Of course, plans are plans, and I have not done anything this winter. 
Sailing season starts next weekend.

Let me know how you end up installing your holding tank.

Fair winds,
Steve G
SV Kefee
Galveston Bay




Do you have any evidence that Kelly Ann ever had a holding tank?  My 26 had a pump out hose and deck plate as well as a few large holes that might  have been more holding tank plumbing.  She now has a port-a-potty sitting on a small platform in the head.  Oddly, the port-a-potty was strapped down
upside down when I got her. 

George Istok  -  Le'a
St. Joseph, Michigan




I have both batteries on the port side under the aft dinette seat.  Plan is
to move one battery to the starboard side just forward of the "galley".  I
also have day dreams of moving the stove to the port side next to the sink
and giving up the aft dinette seat.  I don't use it.  I envision a quarter
berth where the stove was and a small nav station above it.  I also want to
put the water system and holding tank back in place with the water tank on
one side and the holding tank on the other.  I'd still have to balance the
galley, and it seems that the icebox is where all the weight is there.
Maybe I can keep the icebox for food and a cooler on the port side for beer.

George Istok - Le'a
St. Josheph, Michigan



Hi Jim,

Yes, I have a suggestion. Forget about a holding tank and a pump out. In
China Doll, my C26 MKII, I installed a Thetford Aquamate 875 or 885
Portable Marine Toilet.  I built a platform in the head and mounted the
unit on the platform.

Jim Haring
China Doll



Can you take a picture and send it to me?  I was looking at self contained
heads as well, but did not think they worked as well.  Enlighten me.

Steve G




Sorry, but you will have to wait till Spring. China Doll is currently on
the hard under a tarp.  The portable head is in my basement. The two will
not be together till mid April. I don't know what you mean by works
better. The self contained portable unit has worked very well for us for
two seasons.  It is simple. It does the job. It is easy to service. At
most twice a season, I refill the top unit with fresh water and walk the
holding tank bottom unit to the toilet in the club to dump it.  If I had
a holding tank, I would have to go to the next harbor for a pump out or
pay a service fee to the "Honey Bucket" tender. For me it is a no
brainer. The self contained portable unit is the cheapest and easiest way
to go.

China Doll




Why do you need to feed the head with water from a tank? Is having an
intake also an issue, is that a local ordinance? I was hoping to keep my
intake as it is and just install the tank. I am going to check out the
compact holding tank.

Jim Danielson




A lot of the bad smell in the head and the bilge comes from biological decay of organisms - algae, bacteria, plankton, etc. -  in the seawater that comes into the boat.

If you use fresh water to flush the toilet and can keep seawater out of the
bilge, the boat will smell a lot better.

Steven Gaber
Sanderling, 1967 C-31 #77
Oldsmar, Florida



Jim, Steve said it more eloquently than I.  The water at the northern end of
the Chesapeake Bay is brackish fresh water.  As such it contains all those
living things that Steve noted, which when they die eventually create a
smelliness that is nasty to deal with even before bodily-digested matter is
added to the contents of a holding tank.  The other secret to minimizing
odors is to use the most impermeable hoses you can buy (at an outlay of $7
to $8 a foot).  This is one of the reasons why I'm using the Raritan Compact
Holding Tank--the hose runs are minimal.

Dan Johnson
1972 Coronado 27 #316
On the hard in North East, MD



Well I got into the frozen boat this weekend and took some measurements. I
came up with 2 separate options for a holding tank system.

One is to put a traditional 5 to 6 gallon tank, under the port side of the
v-berth. I could run the pumpout, through the bulkhead under the sink and
through the deck over the head. Vent about the same and install a diverter
valve near the seacock.

The other is a little more complicated but might offer a better system. I
could make a custom 3 gallon plywood epoxy tank and install it directly
over the head.( where that little shelf is over the sink.). I could then
run the head pump-out directly to the tank. The tank discharge is at the
bottom of the tank with a tee. One side of the tee goes to the pump out
directly over head, the other side to the discharge seacock. If I remove or
lock the handle the system is completely legal. I can drain the tank by
gravity when I am 12 miles offshore, or when I put the boat up for the
Winter and want the tank clean.

I figure the whole system will run less that $100. Mostly because the tank
will be above the waterline and I can get away with cheaper fittings there,
I have the plywood and epoxy already.

Jim Danielson


Jim, do I understand it that you will build a holding tank of plywood, seal
it with epoxy, place it about chest high, and hope that it neither leaks or
smells up the boat? 

I'd use a Todd tank that will fit that space rather than try to build one
and put the boat's interior at risk with a health hazard leak.  MHO.

Dan Johnson
1972 Coronado 27 #316
On the hard in North East, MD



Daniel Johnson writing to Jim Danielson is really confusing - could you guys use
different names?  ;-)

Mike Keers made a plywood/epoxy tank in his Defender and it worked out OK, but I'mnot sure how much he used it being in the Sea of Cortez.

My concern is tank size.  I put a 6 gallon tank in Binary, my Col 24, and it was barely enough for two people for a weekend.  I think the couple who bought the boatfrom me later agreed.  That installation used the tank well because it drained from the bottom rather than through a typical side outlet.  The side outlets start to suck air when there is still an inch or so in the bottom of the tank.  That's a big percentage of the volume of a six gallon tank.

Regarding using cheaper fittings because the system is above the waterline - sure, a leak won't sink the boat, but you might wish that it did.  ;-)

Whatever you do, test the system with fresh water before you put it in use.

Eric White



feel pretty confident that I can make a leak proof tank. It is also
possible that I could get a polypro tank welded up at a local shop. The
Todd tank does not have the fittings at the proper location and I would
have to relocate them anyway. I made my own dink out of plywood and epoxy
and it has been leak free for 6+ years. Many boats built of wood epoxy have
built in water and holding tanks, that have remained leak free for many

I don't believe having it chest high makes much difference. It fact, it
makes me take notice of any leaks that do happen that much sooner.

Jim Danielson



I am familiar with the plywood/epoxy building method.  Holding out seawater
and containing potable water without leaks is one thing.  Holding tank
permeability would be my concern.  Once it leaks and the odor gets into the
wood, a thorough cleaning won't be able cure it.  Maybe one of the flexible
tanks as a bladder inside?

Dan Johnson



As usual, I'm going to talk about something that I know nothing about.
Maybe I'll get some others talking that way.  (It's worked in the past!)
One of the guys here in town that installs engines and does a lot of other
work on boats told me that to make an integral tank that I should not use
epoxy or polyester, but vinylester (sp?). He says it makes a much less
impervious surface, is almost totally chemically inert, and flexible enough
to resist cracking in all but the most extreme cases.  He also suggested
that I make a plug and form the tank around that and not try to coat a
plywood box.  He told me that if I wanted to make the tank integral that I
should make up panels out of glass and vinylester and install them as I
would a normal plywood bulkhead and then line the entire tank with another
layer of glass and vinylester.  Comments?


Personally I would be worried more about the plumbing aspects of an
integral tank. My poly holding tank (under v-berth) has an inlet, an
outlet, a large diameter clean out, and two air vents. It's not quite as
easy as making a sealed box. (Not that that would be that easy)... If
the area you want to put the tank is accessable and there is a ready
made poly tank that would remotely fit, that is the way I would go. I
took my tank completely out (after it was pumped out of course) and
after removing the 5" or so clean out, was able to blast the interior
sparkling clean at a car wash. Pretty handy to be able to remove the
tank when things go bad.

BTW, when you carry a small holding tank (or porta potty for that
matter) down the dock to your truck you'd be amazed what a wide berth
people will give you. ;-)

Mark and Kathi Banks
1977 8.7 # 168
Stockton Sailing Club
Stockton, Ca.



Hi Bob,

I'll go along with the not coating a plywood box unless you form the tank inside the plywood.

Eric White



You guys are starting to make me uneasy. Perhaps I'll weld one out of
stainless or polypro.

Jim Danielson
Toray Plastics America
Phone  401-294-4511, x3348
Fax       401-294-1099
Beeper  401-325-7985



Hi All,
I was able to fabricate a holding tank in the triangular space under the vanity where the pan and the outer hull come together.  I just glassed in a third panel of plywood and added wood strips around the upper edges to have something to screw the top to.  I then lined the whole thing with a couple layer of mat and cloth. So far its worked pretty well.