Holding Tank Upgrade

Brian Davin · Post by **Brian Davin** » Thu Mar 02, 2006 11:38 am

I've decided to change my holding tank for two reasons: 1. Increased capacity - current one measures 28"L x 14"W x 11"H and is located under the steps in the water tank compartment. Using Ronco-Plastics conversions chart, that size holds approximately 17 - 18 gallons. 2. The 28" length makes my tank hang out into the step down area with the distribution "T" extending even further. I'd like to have more step down room and less risk of steping on the "T" fitting. Breaking that fitting would not be a pleasant thing for a weekend on the boat. Thanks to Al mentioning Ronco-Plastics in a previous thread, I did some searching on their website for different size holding tanks and found two that work. I'm going with one that is 23 1/2"L x 23"W x 12" high which should solve both of my objectives and increase my capacity over 50% at 26+ gallons. Before I pull the trigger, does anyone have any other suggestions or recommendations? Brian '90 Bertram 33' FBC Never Say Never Westbrook, CT (Homeport) Kinnelon, NJ (Home)

photo finish · Post by **photo finish** » Thu Mar 02, 2006 1:35 pm

get the thickest walls that you can

lobsta1 · Post by **lobsta1** » Thu Mar 02, 2006 2:07 pm

Brian, Ronco are 3/8" thick. Have them put the dip tube from the TOP. If a hose leaks or you get a clog, then gravity will not be in your face. Just remember you need 5" clear on top of the tank for the elbow. Also put an oversize vent in. Put the biggest hose that you can find a vent fitting for the thruhull. )Within reason of course) The larger vent will aerate the tank much better & keep the odors down. Ask Ronco for their advice. They are very helpful. Al 1978 33 FBC NITES OFF

lobsta1 · Post by **lobsta1** » Thu Mar 02, 2006 5:15 pm

Brian, Just copied this from the boatered site. It is from Vic Willman. He is head of CS at Raritan. "Posted - 01 Mar 2006 : 08:59:51 -------------------------------------------------------------------------------- In my opinion, 5/8" hose is NEVER big enough - 3/4" is absolute minimum. A good number of boat builders use 5/8" hose and fittings for obvious reasons - cost! That's why so many holding tanks stink! For most boat builders, a holding tank is an afterthought - something they've got to do, but would rather not...in order to get Coast Guard approval so that they can sell their boats. So they use the absolute minimum that they can get away with - and the results "speak" for themselves. Male jokes notwithstanding, holding tank vent lines is one specific area where "bigger is always better." My personal recommendation is to step things up to 1" I.D. if at all possible. The more air you can into the tank, the happier you (and your dockmates) will be." Al 1978 33 FBC NITES OFF