Flexible Fuel Tanks

[Sweetiepie]

We need to change the black tank in our Tayana 37. Is it crazy to think about a collapsible tank rather than the standard aluminum? Is there a problem with them? We are considering, but dont know the pros and cons. Thanks!

[Mike OReilly]

Hi again Sweetiepie. This is something we are considering for our Rafiki-37 (kissing cousin to the Tayana-37). We have two black iron tanks on our boat. We had them cleaned and pressure tested before purchasing. We found that the smaller fore tank leaked, but the larger aft one tested fine, so we're running with just the one tank now (90 gallons).

I've been investigating the idea of cutting the top off the smaller tank and inserting a diesel bladder. This would reduce the volume, but other than dealing with chafe issues, I haven't found any reasons not to try.

[Cheechako]

I assume by Black tank you mean sewage. Anything but aluminum! Welded plastic is good. Tube Depot etc...

[belizesailor]

Originally Posted by Mike OReilly

Hi again Sweetiepie. This is something we are considering for our Rafiki-37 (kissing cousin to the Tayana-37). We have two black iron tanks on our boat. We had them cleaned and pressure tested before purchasing. We found that the smaller fore tank leaked, but the larger aft one tested fine, so we're running with just the one tank now (90 gallons).

I've been investigating the idea of cutting the top off the smaller tank and inserting a diesel bladder. This would reduce the volume, but other than dealing with chafe issues, I haven't found any reasons not to try.

Installed one a in a previous boat to replace the old black-water tank. In my experience, they work quite well, but the critical part of installation is cutting the hole for the fittings very precisely correct -- even a slight bit off and they may leak around the fitting. Ideally get all the fittings you need professionally installed and then do the rest yourself. The fittings are easy to instlall, but if you are off on the hole by just a fraction then there maybe problems....and there is no way to fix them except to start over with another bladder.