Disadvantages of bladder tank?

[summercamp]

A new project of mine, a Frances 26, has bladder tanks for both the fresh water and waste holding. Both need replaced. I have never used bladder tanks and am debating the pro and cons of bladder versus rigid tanks. Access would allow a rigid tank installation.

What are the advantages and disadvantages of bladder and rigid tanks?

Thanks!

[swisscraft]

Hi, flexible Tanks have just one advantage: Access trough a small hatch or so, can expand in there and therefore more Volume in a dedicated, inaccessible space. Thats it - If you can fit rigid tanks and you would be happy withe the volume its a no brainer: safer (no chafe), longer life, mostly cheaper, possible to clean, better ventilation (a big thing with black water), better to secure agains movement and many more I guess.

[S/V Alchemy]

Couldn't express it better. I might have a bladder for potable water in a small cruiser to utilize a small space, like a galley or a head, but I would not have a bladder for black water. Movement cause chafe and cracks in connectors, and as I've experienced a failure of a HDPE holding tank of the solid, well-mounted variety, I would not wish to tempt fate a second time.

Yuck.