adding a holding tank

[Stevelandino]

I have a 1999 Gulfstream 232 with a head that pumps overboard. I'd like to add a holding tank. Any experience out there on how to retrofit my Grady with such a tank? Thanks for your suggestions.

 

[seasick]

I have a 1999 Gulfstream 232 with a head that pumps overboard. I'd like to add a holding tank. Any experience out there on how to retrofit my Grady with such a tank? Thanks for your suggestions.

There were three options for that year: Deck pump out, Portable with macerator and portable. I assume you have the macerator option which I suspect has no holding tank. I would give Grady a call to see what guidance thay can give as to the possibility of an upgrade to the deck pumpout option. I expect the job would be fairly complicated but doable.

 

[DennisG01]

Great idea! It's an excellent thought to help keep our waters cleaner.

The basics of the job are pretty straight forward...

-- Plumb the macerator to the new holding tank (as short as possible and try to eliminate dips in the hose), instead of the seacock (close and cap it).
-- Add a waste pump-out deck fitting in the location of your choice. You don't HAVE to put it where the factory would of - put it where it is convenient for you. The factory installed it while the two halves of the boat were apart - you don't have that luxury.
-- Plumb a 1-1/2" hose from the tank to the deck fitting (as short as possible and as vertical as possible). Double check me on this, I'm not sure if a metal fitting will need to be wired to your ground system.
-- Install a 5/8" deck vent fitting and plumb a hose to it (same idea - as short as possible and no dips), with a "no smell" filter plumbed inline.

You can get tanks (I'd go with at least a 10-gallon, more if you can't get to a pump-out station on a regular basis) from companies like Todd, Moeller, SeaLand -- probably others. SeaLand makes "kits" - as well as a company called Vetus. If you don't go with a kit, then you'd obviously need the various fittings for the tank side, but all of this can be easily sourced a good marine retailer. Of course, good sealant (not 5200) for the deck fittings, various SS hos clamps, zip ties, etc, etc.

Make sure you get odor-proof, reinforced hose for both the 1-1/2" and 5/8" hose. The hose isn't cheap, but don't skimp on it.

Now, although the "basics" are pretty straight forward, the actual installation can be challenging. Often time you're working in cramped areas - and many times by feel only. This is why planning the installation - looking at the materials you'll need and the available spaces you have to put it - is key. It really isn't "hard", but it will be time consuming. On the plus side, you already have the toilet and the macerator - which saves you both a bunch of money and time. But, if it's not something you're really up to, I would first take a good look at those kits as they do make it easier. OF course, having your local yard do the install is a good option, too.

 

[Stevelandino]

Thanks for the great information DennisG01. It does sound challenging. Not sure where the best place for the tank would be. I am leery conducting major surgery in my cabin, so will look into the kits and contact Grady for their 2 cents on the best location. I appreciate your comments very much.

 

[DennisG01]

Where is the current thru-hull/seacock for the macerator? I would "assume" it's not in the cabin and if that's the case, you likely wouldn't have to do anything in your cabin. Everything could be done in the cockpit/bilge. I don't know your model well enough to say, but do you have any under-floor storage somewhere under the cockpit floor? Maybe a spot where an aux fuel tank would be, but the tank was never originally ordered when new? I would, again, "assume" that it might be easiest to run your new hoses to the transom, as opposed to a port or starboard gunwale (which, in most boats, is the typical location for the pump-out deck plate).

Of course, if you have some room, the next challenge is if the you actually get a tank into there, depending on how large the access area is.

Another option could be to change over to a simple porta-potti with either a 2-1/2 or 5-gallon "storage" area built in. They're inexpensive and simple. Not the prettiest of things, but there's really nothing that ever goes wrong with them and they're easy to clean/empty. You could also plumb it as a pump-out. In that case, no macerator is needed - just the two hoses to deck fittings, which can pretty much be put anywhere.