black water tank size

[mcgann454]

Morning all,
I am refitting for a probable start to the loop in Sept of 2018.
I am assessing/rebuilding each system so I know the boat inside and out and the waste system is currently on my to do list while on the hard.
I have a 42' Heritage East Nova Sundeck with two bathrooms. The master has a new freshwater Raritan Marine Elegance and the forward head will have the Raritan Atlantes that came out of the master. It uses water from a through-hull.
It will be the admiral and I for the majority of the time with open invitations to our marina and other friends to come and roll with us for a week or so when available.
Currently I have a 40 Gal. black tank and 150 gal. fresh tank.
I have two 150 gal Diesel tanks and twin Perkins that hopefully will sip diesel so time between refueling and pump outs will be longer.
I now have the opportunity to add or replace the 40 gal. black tank.
Is 40 gallons enough or should I upgrade or add while I can?
Thanks in advance.

[meridian28]

Go bigger if possible. Two of us get a week on our 40 gal tank.

[ranger58sb]

Originally Posted by mcgann454

Currently I have a 40 Gal. black tank and 150 gal. fresh tank.
I now have the opportunity to add or replace the 40 gal. black tank.
Is 40 gallons enough or should I upgrade or add while I can?

A real 40 isn't horrible. Our "40" is really about a 26, due to wall thickness, fitting locations, etc. Might be useful to assess whether your 40 is really a 40.

If the tank is in good shape, instead of replacing it or adding another, you could consider adding a Purasan treatment system and plumbing it to use you existing tank as part of a "Hold 'N' Treat" system... so you're covered in NDZs.

I suspect if it were easy to replace the existing tank with something larger in the same place, or adding another somewhere so each head has its own dedicated tank and ideally positive gravity feed from bowl to tank... and if I had a healthy budget ... maybe I'd consider bigger/more tanks AND the Purasan.

Happy to help you spend your money.

I haven't paid much attention to it, but haven't heard Loopers complain about finding pump-outs, though. You might check AGLCA if you haven't already.

-Chris

[donradcliffe]

Two holding tanks would be twice the bother. In the GB42 we had 60 gallons of black water, 250 gal of fresh, and 600 of fuel. The forward head used water from a through hull, and we let it discharge overboard and only used it to pee in. The back head was a freshwater Atlantis.

The black water tank would easily hold the output of 4 people for a week. Using freshwater flushes put an additional load on the freshwater system, but we never came close to running out of freshwater.

The 600 gallon fuel tanks gave us a range of over 1200 miles at 7.5 knots, even with genset use 4 hours/day. This provided us the opportunity to bypass fuel docks and stock up with cheaper fuel.

Pumpouts in Canada are available, but are more expensive than the subsidized ones in the US.

[mcgann454]

Originally Posted by ranger42c

A real 40 isn't horrible. Our "40" is really about a 26, due to wall thickness, fitting locations, etc. Might be useful to assess whether your 40 is really a 40.

If the tank is in good shape, instead of replacing it or adding another, you could consider adding a Purasan treatment system and plumbing it to use you existing tank as part of a "Hold 'N' Treat" system... so you're covered in NDZs.

I suspect if it were easy to replace the existing tank with something larger in the same place, or adding another somewhere so each head has its own dedicated tank and ideally positive gravity feed from bowl to tank... and if I had a healthy budget ... maybe I'd consider bigger/more tanks AND the Purasan.

Happy to help you spend your money.

I haven't paid much attention to it, but haven't heard Loopers complain about finding pump-outs, though. You might check AGLCA if you haven't already.

-Chris

Chris,
I have to add or replace the tanks in the current location. It is not ideal as it is too far away form the master head using Peggy Hall's recommendations, but there isn't a location closer to the master head and I really would rather just pump one tank when fueling.

I am a member of AGLCA and was searching there for thoughts on the blackwater tank.

My inlet is on the side although it is as high on the side as possible, it does cut the total storage a bit. I looked at the Purasan and a quick check on amazon shows about a $1600 investement. Ouch, but I will do some more research.

Thanks for the thoughts.

[mcgann454]

Originally Posted by donradcliffe

Two holding tanks would be twice the bother. In the GB42 we had 60 gallons of black water, 250 gal of fresh, and 600 of fuel. The forward head used water from a through hull, and we let it discharge overboard and only used it to pee in. The back head was a freshwater Atlantis.

The black water tank would easily hold the output of 4 people for a week. Using freshwater flushes put an additional load on the freshwater system, but we never came close to running out of freshwater.

The 600 gallon fuel tanks gave us a range of over 1200 miles at 7.5 knots, even with genset use 4 hours/day. This provided us the opportunity to bypass fuel docks and stock up with cheaper fuel.

Pumpouts in Canada are available, but are more expensive than the subsidized ones in the US.

Don,
With the longer range, did you find you had to stop and pump out without getting fuel? I know we will spend some time at marinas and most have pump outs there, but when fueling, they usually pump it for you.
Thanks
Mike

[ranger58sb]

Originally Posted by mcgann454

... and I really would rather just pump one tank when fueling.

I looked at the Purasan and a quick check on amazon shows about a $1600 investement. Ouch, but I will do some more research.

Good point, about pumping one tank. I'd like to think I'd have eventually twigged on to that issue.

Yeah, not inexpensive, although not quite as bad if you can do the installation yourself. At least you wouldn't have to buy a new tank to make it a "Hold 'N' Treat" version; your existing could work like a champ for that. And if that's all you do, then you won't have spent anything on new tanks.

Originally Posted by mcgann454

Don,
With the longer range, did you find you had to stop and pump out without getting fuel?

We've often had to do that; don't use much fuel in the grand scheme of things, compared to the overall time we spend on the boat. Not considered a big deal, at least in our neck of the woods.

-Chris

[Dave22q]

I believe 15 gal per person per week is a reasonable estimate for average users. Of course overly enthusiastic flushers can up that number considerably.