H31 Built-In Holding Tank

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Laura Bertran

I am in the process of refitting a 1985 H31 that I recently bought. This weekend I inspected the head and holding tank set up. The head is plumbed to a vented loop and then directly to a through hull for overboard discharge. It appears that the built in fiberglass holding tank has never been used since the tank outlet nipple has no hose on it and there is a hose running from the pumpout deck plate to the tank nipple that should run to the toilet discharge. I'd like to know what kind of experience, good or stinky, others have had with the built in V-Berth fiberglass holding tanks. How do they hold up? Do they smell? Does the seal on the V-Berth cover plate need periodic redoing? It would be a relatively simple matter to connect new hoses properly from the head to the existing holding tank and replump the tank outlet to the pump out deck plate. But since the tank is clean, it is an opportunity to install a bladder or other tank inside it if folks have found the built in tanks to be unreliable. I'd appreciate any advice. Thanks. Laura Bertran 1985 H31, Rising Tide
 
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Ed Schenck

Glass tanks.

Just went through this with Peggy and others. They convinced me that fiberglas is permeable and would eventually hold the odor if not downright leak. So I replaced my v-berth bladder tank with a plastic tank from Ronco. That experience convinced me there really wasn't much wrong with the bladder. When I removed it I could detect no odor from the tank, it was all in the hoses. The main problem with a bladder tank is that the discharge connection is at the bottom. This causes the waste to seek the same level in the discharge hose. So you end up with two or three feet of hose that always has "stuff" in it and eventually it's going to stink. Even knowing that I would opt for putting a bladder inside your current tank. Then use the good Sealand hose($8./foot). While I am here the other problem with a bladder? Unless you can put it in an existing tank there is no good way to secure it. There are two corner grommets for bolting it down. Adequate for coastal cruising but nothing more. You won't have that issue.
 
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Peggie Hall/Head Mistress

In addition to Ed's comments...

Fiberglass is water-absorbent...even a hairline crack in the gelcoat will allow the fiberglass to soak up waste, water, or whatever is in the tank...leading to serious problems that won't be discovered until they are serious. When the tank is integral to the hull, that affects the structural integrety of the boat. Bladder tanks don't necessarily permeate any more than any others, but because the fittings are owner installed in 'em, they are highly prone to leaking. They're also highly prone to blow out a fitting at the least sign of a clog in the vent. And, because they're designed to "hug" the contents, it's almost impossible to prevent odor from belching out the vent each time the head is flushed...read the article "Holding Tank Odor--Odor Out the Vent" in the Head Mistress forum Reference Library (on the right side of the forum homepage) for a detailed explanation. In fact, I suggest you read all the articles there. Good quality, thick-walled (at least 3/8") polyethylene is the material of choice for waste (or water) holding...and I highly recommend Ronco Plastics. they make TOP quality, thick-walled roto-molded tanks, and have more than 400 shapes and sizes--over 100 of which are non-rectangular--to choose from..and for a VERY reasonable price. I'd bet they have one that will fit your space. And you can spec your own fittings sizes and locations, to be installed by them when the tank is made. Their catalog is on their website at: http://www.ronco-plastics.com As for hoses, the SeaLand OdorSafe brand is the only one I recommend any more. At $8 /ft, it is expensive...but I've yet to hear of a single case of odor permeation failure since it's been on the market. So which is really more expensive--$3 /ft hose that has to be replaced every few years...or $8/ft once? And btw...rubber o-rings or gaskets on ALL inspection ports have to be replaced every few years...the rubber dries out, becomes brittle and ceases to seal. It's not a big deal...just another maintenance item.
 
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Laura Bertran

Question for Ed Schenck

Ed- I'm not sure I fully understand your post. Was there originally a bladder tank inside the built in fiberglass tank? I was assuming that the tank did not have any kind of a liner. Did you install your Ronco tank inside the original V-Berth tank? If so, do you remember what model number you used? Thanks a lot for the info. Laura Bertran
 
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Ed Schenck

My unclear response.

Sorry Laura, but I have an H37C not an H31. I was oversimplifying to spare you the gory details. The H37Cs originally came with an aluminum tank glassed to the hull and then overlaid with the hull liner! The tank ended up under the shower seat. Most have been replaced in some fashion because they all leaked(or will). A previous owner had simply hung a bladder tank on the flat aft-facing bulkhead inside the center v-berth locker. I replaced that with a Ronco tank(34"x12"x12") in that same space. I had planned on constructing a fiberglass tank in the starboard locker of the v-berth but was talked out of it on this forum. The consensus was that a plastic tank will not aborb waste but fiberglass eventually will. I made several tank templates before finding one that would fit and still allow me access to the bottom of the locker. That is where my log and depth thru-hulls are located. Even at that I had to enlarge the top opening to get the tank in there. Big project.
 
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Laura Bertran

Big Thanks!

Peggy and Ed- Thanks so much for taking the time to help me think out this project. I'll definitely be using Sealand Hoses. But I haven't yet decided whether to use the existing fiberglass tank or install a poly tank. I've got some more thinking and measuring to do this weekend. Laura Bertran
 
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Ed Schenck

Helping you think.

This might be one of those times when doing it twice is not a bad idea. Especially if you would rather be sailing then tearing the boat apart. Go ahead and plumb the head to tank and tank to pumpout with Sealand hose. This will last you a few years at the very least. If the tank does eventually permeate then make that an offseason project. Ronco makes so many sizes and shapes that you can almost certainly find one to fit. But it will probably require making the v-berth hatch much larger. Go sailing!
 
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Peggie Hall/Head Mistress

I gotta disagree, Ed...

By the time you discover that inside of the tank is leaking, either through hairline cracks in the gelcoat or a fitting nipple that's lost its seal, the fiberglass can soak up so much moisture--and VERY smelly moisture!--that repairing it is likely to be a major job...and an expensive one too. 'Cuz the tank won't necessarily leak--as in, allow the contents to escape completely...only the inside may leak, saturating and rotting the f'glass.
 
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