We had a bladder on a previous boat. I was washing it one day and the bilge pump kicked on, which had never happened before. I smelled it before I saw it. The PO had patched a hole on the underside of the bladder, which failed. We replaced the bladder with another bladder and never had an issue, but I have to advise against ever patching a bladder.No one has mentioned bladder tanks yet. My Alerion came with one (I forget the brand) and I have no complaints. Bladders are widely used for fuel and other nasty stuff, so the technology is there. They probably don't make maximal use of the space available, but it is easy to see when you need a pumpout with just a glance. The fittings may not be best positioned for gravity drainage, but customization is possible.
I'm sure a bladder could work fine but I have a problem with having a big plastic bag of sewage on my boat.We had a bladder on a previous boat. I was washing it one day and the bilge pump kicked on, which had never happened before. I smelled it before I saw it. The PO had patched a hole on the underside of the bladder, which failed. We replaced the bladder with another bladder and never had an issue, but I have to advise against ever patching a bladder.
The problem with using a bladder tank for holding sewage is that you are creating an anaerobic environment, which is even nastier than what normally breeds in there. Nobody likes to think about venting a holding tank but it's actually very important for multiple reasons including microbiology and for pumping in or out.No one has mentioned bladder tanks yet. My Alerion came with one (I forget the brand) and I have no complaints. Bladders are widely used for fuel and other nasty stuff, so the technology is there. They probably don't make maximal use of the space available, but it is easy to see when you need a pumpout with just a glance. The fittings may not be best positioned for gravity drainage, but customization is possible.
If you buy the good ones, they are incredibly tough. The Army drops "big plastic bags" of diesel fuel to mech troops in the desert. Yes they drop them low and slow but I think your average tank would not do as well plummeting from a C130.I'm sure a bladder could work fine but I have a problem with having a big plastic bag of sewage on my boat.
I based my attitude on experiences with waterbeds in the 70's.The problem with using a bladder tank for holding sewage is that you are creating an anaerobic environment, which is even nastier than what normally breeds in there. Nobody likes to think about venting a holding tank but it's actually very important for multiple reasons including microbiology and for pumping in or out.
If you buy the good ones, they are incredibly tough. The Army drops "big plastic bags" of diesel fuel to mech troops in the desert. Yes they drop them low and slow but I think your average tank would not do as well plummeting from a C130.
Mixed reviews on that. I only had two. One sprung a leak after a couple of years (on a seam of course) and one was fine until long after I sold it. But they also were prone to microbiology problems if you recall... and I don't mean the sheets...I based my attitude on experiences with waterbeds in the 70's.![]()
Cardboard works, or thin doorskin ply hot glued together.
Yep. Always use cheap stuff for the prototype. Especially if you're like me and get to the Mk 3 (or later) version before you're happy with it.Ah, yes: C A D
Cardboard Aided Design