Holding tank access

Jan 28, 2017
23
O'Day 34 Suttons Bay
I’m ready to replace the head and hoses in my OD34. Spoke with Peggie Hall who recommended replacing the stock 15 gal holding tank with a 20-25 gal for extended gunkholing.
My question: is the fiberglass pan of the vee berth removable to access/replace the tank or would I have to cut out a larger access port? I know there are smaller access ports but never noticed if the pan was removable.
Appreciate any advice.
 
Dec 2, 1997
8,132
- - LIttle Rock
Is the tank buried under a pan? I thought from our conversation this morning that there's just a panel--or panels--over it that support the v-berth mattresses.

-Peggie
 

dmax

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Jul 29, 2018
503
O'Day 35 Buzzards Bay
Here's a link from someone who replaced theirs, if you want to go larger, you need to cut some fiberglass:
 
Jan 28, 2017
23
O'Day 34 Suttons Bay
Is the tank buried under a pan? I thought from our conversation this morning that there's just a panel--or panels--over it that support the v-berth mattresses.

-Peggie
Sadly, there is a pan with rectangular ports. I don’t know if it is glasses to the hull or fastened (will inspect on my next visit to the yard). Was hoping someone here might know.
 
Jan 28, 2017
23
O'Day 34 Suttons Bay
Here's a link from someone who replaced theirs, if you want to go larger, you need to cut some fiberglass:
Thanks for this link. Great photos and I’m guessing no easy access given the similar dimension replacement tank selected.
 
Aug 17, 2010
269
Oday 35 Barrington
Background: The head and holding tank on my 35 had been replaced by the previous owner with a Vacuflush head and holding tank system. When I bought the boat it was not working. I removed the "professional" installlation, and rewired, replumbed and re-installed the entire thing. After sailing with it for 9 years, I LOVE it!

Your question: The fiberglass pan under the V-berth was not meant to be removable. It IS possible to cut additional access panels into the pan. If you do, realize that there are also fiberglass stringers (stiffeners) that you will be cutting. My boat has an additional access panel cut to allow better access under the "point" of the V-berth. The stringers are relatively simple; multiple pieces of fiberglass cloth wetted out with epoxy, and left to set over a broom stick, or piece of pipe, so that they form an inverted U shape. The stringers are then epoxied and tabbed into the underside of the pan.

Other points:
  • While I agree with Peggie Hall, I have found that my 10 galon holding tank, when used with the Vacuflush head, is good for more than 8 person /days before requiring a pumpout.
  • Also the hose routing on the O'day 34/35 is TERRIBLE. There are many spots where dips will hold the effluent, and the hoses will start to smell. I cut new holes to run the hose for the pumpout fitting, and used schedule 80 PVC pipe (with flexible hose spliced to the ends) to complete a run from the head to the V-berth.
 
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Dec 2, 1997
8,132
- - LIttle Rock
: The fiberglass pan under the V-berth was not meant to be removable. It IS possible to cut additional access panels into the pan. If you do, realize that there are also fiberglass stringers (stiffeners) that you will be cutting.
So I read this correctly, it's impossible to replace the holding tank--even with same size in the event it splits or cracks...only possible to replace hoses?

If so that's a real shame because there's enough space above the top of the tank to put all the fittings ON the top of the tank with a pickup tube inside it on the discharge. Inlet and vent fittings on the end or side of a tank reduces the useable capacity by at least 2 gallons 'cuz the contents rising above the bottom of those fittings spill into the hoses.

--Peggie
 
Aug 17, 2010
269
Oday 35 Barrington
I feel honored to have Peggie quote my post in hers! But, yes, you read that correctly. I believe that the engine and ALL of the tanks were installed into the hull before the floor pan went in, because it cut production time, and therefore cost.

Realize that O'day went out of production in 1990, so these boats are 30+ years old. Yet, there are still quite a few of them around, so they must have been on to something. I suspect that the PO of my boat cut the holding tank into pieces before removing it.

I have given consideration to cutting the pan under the V-berth to leave only a 2" flange and the stringers, and then to cover the whole thing with two pieces of 3/16" plywood cut to conform to the shape of the current V-berth cushions. I would then screw the plywood into the flange and the stringers to hold it in place.

Below is a drawing and two pictures, courtesy of the PO of my boat, showing the dimensions of the standard pan and tank in an O'day 34/35;
H & HT 1.JPG
H & HT 2.JPG
H & HT 3.JPG
 
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Aug 17, 2010
269
Oday 35 Barrington
Adding that my current installation has both a holding tank (I'm not really sure of the size TBH) and the Vacuflush vacuum generator (separate units) on the platform that the old holding tank was strapped to. My current holding tank has all the connections on the top of the tank, and uses dip tubes for the pump out and macerator connections. I mentioned in a prior post that I had to cut new holes in the pan to run the hoses so that there would be no dips, and so that any effluent in the lines drains back into the tank.

Also (and I am surprised at how many people don't know to do this) I ALWAYS rinse the hoses and the tank by pouring a gallon or four of fresh water into the deck pump out fitting after I have pumped out the contents of the tank. I then pump the tank out again so that the tank is nearly empty.
 
Aug 11, 2011
662
O'day 30 313 Georgetown MD
On my 30, I actually took the whole tank out through the openings. In order to do it you need to take all elbows off. This was not a pleasant job. I pumped out multiple times before starting the task, but you don't get all the liquid out and I still needed to do a major clean up job. Once the tank was out I soaked it for days with Limeaway and got rid of a lot of the buildups. It looks like the pan was installed as eherlihy describes as when I removed the pan or base there was no interior gelcoat or paint. The fiberglass tabbing was sub par, so when you do yours I recommend going a little overboard (no pun intended) with the reconstruction of your base and surrounding areas.
 
Jun 11, 2004
1,221
Oday 31 Redondo Beach
On my 30, I actually took the whole tank out through the openings. ... It looks like the pan was installed as eherlihy describes as when I removed the pan or base there was no interior gelcoat or paint. The fiberglass tabbing was sub par, so when you do yours I recommend going a little overboard (no pun intended) with the reconstruction of your base and surrounding areas.
Sorry, I'm confused. Did you get the old tank out through the existing openings or did you have to cut the pan to enlarge the openings? Maybe i'm misinterpreting the term "pan". I am assuming that pan means the fiberglass structure the rectangular openings are in and the bunk cushions sit on.

Thanks
 
Aug 11, 2011
662
O'day 30 313 Georgetown MD
Tank came out through the original openings, but first the plumbing elbows has to be removed. The pan is the base the tank sits on. That is shaped to the v of the bow, a style of box, which is tabbed to the inside of the hull walls. I'll send pictures once I figure out how to get them off my google drive.
 
Jun 11, 2004
1,221
Oday 31 Redondo Beach
Tank came out through the original openings, but first the plumbing elbows has to be removed. The pan is the base the tank sits on. That is shaped to the v of the bow, a style of box, which is tabbed to the inside of the hull walls. I'll send pictures once I figure out how to get them off my google drive.
Thanks. That's clear I get it. No need for the pictures. I appreciate the response.
 
Aug 11, 2011
662
O'day 30 313 Georgetown MD
Copy of IMG_2681.jpeg


The dark area is where I removed the old pan area. It was made from plywood and was totally rotten. Once I cleaned up the area, I built a new pan to replace the old using PVC board. No rotting, no smells and easy to clean

Copy of IMG_2690.jpeg


With the clean tank installed with retaining straps
IMG_2691.jpeg
 
Sep 23, 2009
1,455
O'Day 34-At Last Rock Hall, Md
I replaced my old tank thru the opening but had to cut about an inch off of two sides to get the new larger Ronco tank in. So far I just skew the plywood cover to support the mattress.
The tank tips down at the forward side so I need to make a new angled support floor to get the low spot aft where the pump out stand tube is.
The hose routing is not optimum. I still have a low spot going to the deck pump out but figure the pump out suction may keep that low spot clear once the tank is pumped empty?
I did this about three years ago and still order free thanks to the Raritan hose and Peggys advice.
 
Sep 23, 2009
1,455
O'Day 34-At Last Rock Hall, Md
Thanks for the measured photo. I am considering putting an a.c. unit where the v berth step is by cutting the step side sides away and putting the air return across the opening.
 
Jan 28, 2017
23
O'Day 34 Suttons Bay
Do you recall which Ronco tank you installed? I couldn’t find one I was confident would fit so I replumbed the original tank and rerouted the new hoses to avoid the low spots. Here is the pump out and old vent hoses.
4D4D6F2E-C048-4FDF-A455-6607C4BABE81.jpegD4297833-D791-4506-A7E2-54AC54F1BCC0.jpegDF9BCCB9-9786-479A-B966-61B70A4BB0C9.jpeg5B2669F3-CDD6-4317-9C17-90BA16E0A577.jpeg
 
Aug 17, 2010
269
Oday 35 Barrington
Best bet is to have the hoses enter the tank through the top, and use dip tubes for the pump out and macerator (if equipped).

Hoses that enter through the bottom will eventually start to smell.

I like the PVC tubing pictured above, but would want to support them to prevent any possibility of their breaking.
 
Jan 28, 2017
23
O'Day 34 Suttons Bay
I like the PVC tubing pictured above, but would want to support them to prevent any possibility of their breaking.
I agree, it wasn’t my first choice but was easy to fabricate on short notice. It is sturdy with the hoses zip tied together but I think I’ll add a 1x3 protective shield around the PVC in case something starts rolling around in there.
BTW, I upsized the vents to 1 in and moved them to the top of the tank using Uniseals and elbow fittings. When’s it’s warm enough for 4200 I’ll install the forward bow vent through hull. Wasn’t confident enough to do that with the head discharge line (Uniseals are press fit - not threaded) but may consider it if I don’t replace the tank.

524FFB0C-7EDF-4073-84F0-0D02BE1F5EC2.jpeg6DFFBC56-9649-4260-AEB0-5EFDBA481502.jpeg0A6F53CE-8B94-4575-BB26-324E3DD1A5FA.jpeg727143E8-57E8-4BCD-BDE0-F92CA46E620F.jpeg
 
Sep 23, 2009
1,455
O'Day 34-At Last Rock Hall, Md
The tank was boat27w, 19 gal, 32x12x12.
Also if I remember correctly there was a big problem using the grey 1 1/2 inch connectors as they were just too big for the 1 1/2 inch Raritan hose. I believe Peggy suggested changing to white pvc elbow and problem solved.
I highly recommend using top mounted stand pipes for outflow vs bottom outflows that allow standing sewage to flow into the f discharge hose or worse leak..
 
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