New Holding Tanks Installation

[Chris]

Hi Peggy,We (my wife and I) have a Beneteau Idylle 15.50 that is undergoing total renovation (interior). The plan is to have two heads but what about holding tanks? We get so many advice what is the best solution. We were thinking of having one big holding tank for both heads and one idea was to convert one of the hullshaped former freshwater tanks (below floorlevel) to a holding tank. The volume approx. 300 liters. Would it be better to place holding tanks under each head and in that case what volume of the tanks? We are going for worldwide cruising and living onboard. Please help us out. Regards, Chris. P.S. Check out our site to get the interior drawings by clicking related link below.

 

[Peggie Hall/Head Mistress]

Unless both heads will be within 6-8' of a tank,

don't try to connect them to the same tank. Waste will always be left standing in the hose from the more distant toilet. I don't recommend converting your 300 liter water tank to waste holding for two reasons: it's too big, and the location (below the cabin sole) will almost guarantee odors out the vent. For your intended use on a boat that size, I'd recommend two separate systems: a holding tank that can either be pumped out or dumped at sea on the least-used toilet (if it will VERY rarely be used, don't bother with a y-valve that will let you flush directly overboard...it's just one more thing to maintain)...and a Type I treatment device that treats and discharges the waste. That arrangement will make your boat "legal" in any waters worldwide, while offering the maximum convenience. I suggest you read all the articles in the HM forum reference library before doing anything...I think they'll give you a better understanding of how sanitation systems work and how to minimize problems.

 

[Chris]

Thanks Peggie

Thanks for the advice, yes I think we are going for two separate tanks.1: What min/max size would you recommend on holding tanks for our boat?2: I have been looking at a few "zero discharge" systems and understand that you need a holding tank anyway after the treatment tank, is that correct?3: Any system you can recommend to us? (simple but good working)Thanks for your time, Chris.