Holding tanks only empty from deck fitting--solutions?

[pillowfort]

Hi there! I'm looking at a 1981 Gulfstar 44. It has one glassed-in holding tank and one (presumably retrofitted) plastic tank. Reading the past marine survey, I noticed that both only empty from deck fittings.

Is there any way to retrofit something so that we can discharge at sea on longer passages? A macerator, maybe? I suspect that at least one of the tanks is below the waterline.

One possibility would be to replace replace one of them with composting or the like. I'm wondering if there are options beyond that, though? Is adding a new thru-hull for pump out possible if the tank is below the waterline?

Thanks so much!

[Bellinghamster]

Yes, it's definitely possible. You can add a mascerator or diaphragm pump to push "uphill" from a below-the-waterline tank. It's a bummer when they fail, tho. I'm in the process of finding/making space for above-the-waterline holding tanks in my GS50, hopefully able to gravity drain when offshore... it had Lectrosan treatment systems, which are no longer legal in Puget Sound (plus they no longer worked).

[pillowfort]

Ohh really, Lectrosan isn't legal here anymore? That's good to know, thank you! I'd seen some positive reviews of them in the past.

Liking the look of the Raritan pump at the moment. It's already on the hard, so that'll make adding a thru hull easier at least XD