Originally Posted by 44'cruisingcat
The plastic tanks I have have clean out ports
. If they were large enough to need them, baffles could have been built in too. I don't know where passagemaker magazine got their info from.
If you are talking about roto-molded tanks, it is not possible to include real baffles, due to the way they are built. Some have relatively small ridges built in, which the manufacturers call baffles, but I think they are useless.
I suppose a roto-molded tank could be cut open at the top and a plastic baffle could be inserted, but I would be concerned that this would reduce overall strength, add expense, etc. etc. If baffles are necessary, I'd go with fabrication by either stainless or plywood/GRP.
I'm probably going to use either high quality stainless or possibly smaller roto-molded tanks installed next to one another.
(on edit: I see the Vetus tanks do have more substantial baffles built in. They appear to be adequate as baffles, and cleverly done. But the Vetus size and shape selection is very limited. I will contact them to see if they plan to offer a larger selection. There is a roto-molded tank manufacturer in California
that has a much larger selection... I'll also be contacting them to see if they can modify their baffle design to the Vetus type.)