Septic Bladder

Jun 27, 2011
111
Macgreggor/Balboa 26 25/26 Baraga
I currently have a 30 ft. Allied Sea wind Ketch that has a sewer bladder under the V birth. It is really small like one weekend with two adults and its full. Any recommendations of A. What size Bladder would allow two (2) adults not have to pump out out for a week or two B. Where to get such a bladder, C would it be better to put a solid tank in and do they make tanks triangle shaped. I would love to do the compost toilet but the space in the head is to small unless you know of a composting toilet that is out there for sailboats specifically
 
Feb 21, 2013
4,638
Hunter 46 Point Richmond, CA
A - The articles below should be helpful to answer these.


B - Do an internet search on "bladder holding tanks". One source for them is Defender:


C - I would install a solid tank because it is easier to flush out.
 
Oct 1, 2007
1,856
Boston Whaler Super Sport Pt. Judith
I have experience with bladder tanks on an earlier boat. I used them only for fresh water. They were continually finding new ways to leak. However, it was fresh water. I cringe to think about leaking sewerage in my bilge. I used the best, most expensive ones I could find, but they still leaked.
For what it's worth, I would definitely go solid tank.
 
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Jan 1, 2006
7,040
Slickcraft 26 Sailfish
There is a dizzying array of solid tank shapes available in stock sizes the even custom tanks are available.
As for size you need enough for several days of use between pump outs. I would rather pump out more often than carry a larger tank with more contents in it. But for most of my cruising in Southern New England pump outs were readily available.
 
Jun 27, 2011
111
Macgreggor/Balboa 26 25/26 Baraga
A - The articles below should be helpful to answer these.


B - Do an internet search on "bladder holding tanks". One source for them is Defender:


C - I would install a solid tank because it is easier to flush out.
Do they make solid tanks in triangle shape.
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Ronco is a great source for tanks and they have a lot of different shapes/sizes.

If you can get or make an accurate drawing of the tank you want with locations for fittings, etc there is a custom poly tank fabrication places in Maine and also in North Carolina. There may be some closer to you but i don't see your location?

Triple M in Maine Triple 'M' Plastics
Blue Grey in North Carolina Blue Grey Plastic Fabrication - Home
 
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Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
Ronco is a great source for tanks and they have a lot of different shapes/sizes.

If you can get or make an accurate drawing of the tank you want with locations for fittings, etc there is a custom poly tank fabrication places in Maine and also in North Carolina. There may be some closer to you but i don't see your location?

Triple M in Maine Triple 'M' Plastics
Blue Grey in North Carolina Blue Grey Plastic Fabrication - Home
Ronco has a dizzying array of plastic tank sizes. It may be easier to build a cardboard or door skin mock up of what you want and what will fit and as @smokey73 suggests find a nearby plastic fabricator that does custom work. They can cut and weld the polyethylene to your specs. It will be a superior solution to a bladder.
 
Dec 2, 1997
8,709
- - LIttle Rock
Bladders can be a good choice for water, but not for sewage for several reasons: they're highly prone to blow out a fitting at the first sign of a clog or a blocked vent (USCG regs require ALL waste tanks, rigid or flexible, to be vented to the outside of the boat)...it's almost impossible to secure a bladder to totally eliminate chafing /leaking...and even the best ones only have about a 15 year lifespan. A good quality rigid plastic tank will last as long as the boat provided it's not abused.

Ronco Plastics Ronco Plastics marine Tanks is your best source for a tank. They make TOP quality thick-walled water and waste tanks for a very reasonable price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower price...and they're great to work with.

When looking at drawings it's important to know that there is no top or bottom until the fittings go in, and YOU decide where they go. So rotate, flip in any orientation to find the tank that fit your space. Yes, they do have at least a couple of bow-shaped tanks and a whole bunch of "wedge" (triangular) shaped tanks to lie along the hull. Fwiw, Ronco has been the OEM supplier to most of the high-end boat builders for decades.

I'll be glad to help you with the details of selecting the best location for the tank, locating the fittings on the tank and plumbing runs.

--Peggie
 

Mr Fox

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Aug 31, 2017
204
Marshall 22 Portland, ME
If you’re going to do one thing in updating your septic on a boat- it’s listen to Peggie, say it with me, listen to Peggie :)