53 holding tanks

[ian w]

I own a 1981 53 motor yacht and have two questions about the holding tanks .Firstly are the tanks interconnected?It would seem they are not as there are 2 pump out ports.The forward holding tank appears to have inlet hoses from all 3 heads-I would have expected it to cater for the forward head and maybe the middle head but not all three! Secondly is it possible to fit a pump to discharge the forward holding tank through the forward head discharge by mounting a macerator pump on top of the tank.

ian w 1981 53 motor yacht

[Nonchalant1]

The tanks are not interconnected. The forward tank handles the forward and the aft heads. The starboard tank handles the mid head. The forward head raw water intake usually has additional raw water intakes connected to it like a washdown, etc. A macerator pumpout should have its own thru-hull. Also the galleymaid heads have a macerator on the discharge pump so all you need to pump out the forward tank is a bigger pump and a thru-hull, not a macerator pump. I added these to my 1978 53MY and ran T valves on the big PVC pumpout line running to the deck pumpout fittings. You close off the deck pipe, open the pump pipe, open the thru-hull and turn on the pump.

[MikeP]

What Nonchalant said!

If your forward tank actually has outlets from all three heads, someone modified the system...

[TopHattandTails]

On the fwd tank, you will also find a bypass that allows sewage to bypass the tank and flow directly overboard. That may be the 3rd hose your looking at. While within 3 nautical miles and on inbound lakes, close the bypass to flow to tank, remove t- handle, and then I electrical tie nearby the handle so I don't loose it.

[ian w]

Thanks for the help.What is the recommended pump and plumbing to empty the forward 53 holding tank at sea as there are no pumpouts in the majority of the bahamas ian w

[TopHattandTails]

2 steps. 1) wire up a pump to remove tank holdings (see above posts). 2) once tank is empty, discharge over board via y valve. While in marinas, I would y back over to the holding tank and then hit the magic button while out at sea. If it were me, I'd plumb the magic button somewhere inconspicuous (under crews vanity, in galley pump room) - somewhere it wouldn't jump right out at an inspector...

[Nonchalant1]

Thanks for the help.What is the recommended pump and plumbing to empty the forward 53 holding tank at sea as there are no pumpouts in the majority of the bahamas ian w

I used a SeaLand "TW Series" 24V Macerator Pump as did 2 other owners here. Costs about $335. It will run OK on 32V as well as 24V according to SeaLand. I built a shelf out of "starboard" (plastic boards) on the big fiberglass shelf just in front of the sb battery starting bank on the sb side of the generator. I installed a 2" bronze thru-hull with lockable handle there (costs $200 for the valve and bronze bolts) and mounted the pump next to the thru-hull. Then I put a large PVC "T" valve in the forward holding tank pumpout tube which runs right above the shelf there, added a shutoff valve after the "T" and plumbed the T to the pump with 2" PVC. Everything is solid PVC so no hose was used. I wired the pump to a switch with a key installed into the shelf I made and wired that to the sb side 32V starting bank. Since it will only be used when the engines are running offshore, I felt no issue with using the starting bank batteries.

To use it, you have to be running offshore, crawl down into the genny room under the galley floor and around the front side of the genny, open the "T", close the stop valve, open the thru-hull and turn on the pump. Then when the tank's empty, do the reverse of all that. These pumps are powerful and absolutely need a 2" thru-hull, so that was necessary, even though it is scary to add a thru-hull to your boat. The whole system cost about $590 and I did all the work myself.

Doug

[stilespb]

Be careful to check all this good advise with repect to your own vessel. I have inspected many Hat 15'10" hulls and I think the holding tanks and associated plumbing have been different on all of them.