another holding tank question

[dohenyboy]

On a holding tank there are three barbs
1. One at the top of the tank for incoming
2. One midway down which has been connected via hose to the deck pumpout--so that pumpout only removes one half of the tank
3. one at the bottom which goes to the hand pump to the thru hull

Should I leave it plumbed that way or switch#2 and #3 ? I have the holding tank out and it would be just as easy as leaving it as it is.

[sailingdog]

I'd switch #2 & #3. If you're in a marina, the chances that you need to have the holding tanks fully emptied are far higher than if you're out at sea, since using the head on the boat requires that you use the holding tank while in coastal waters.

If you're out where you can pump out to the sea, then it really doesn't matter that it only pumps out half the tank, since you can do it over and over, as needed.

[Valiente]

Where's your vent?

[sailingdog]

Good point... if there isn't a vent currently, the topmost is probably what was
supposed to be the vent. The mid-level was probably the input, and the lowest the output hose. Then you could put a diverter in the output hose to handle the waste output to either the deck fitting or the manual pumpout.

[dohenyboy]

there is a vent. I think that the PO switched the hoses because he was not based in a marina with pump out facilities.

[dohenyboy]

to update, I finally finished installing new sanitation hoses. About 8 sections of hose and and 20 feet total hose.
Here is the process I used.
First I took the boat to the pump out station, filled the holding tank with water, pumped it out, repeated until I was tired of doing it and the water coming out was almost clear.
then I ran some toilet cleaner/conditioner through the system so that when I took off the hoses the fluid that spilled would not be too smelly.
I removed the holding tank, because it was impossible to remove or install two of the hoses while the tank was in situ.
Removing hoses, I cut off the hose at the fitting ,then roasted the remaining bit of hose with a heat gun. Came off easily.
I bought the new Sealand super duper sanitation hose. I am sure its going to last for centuries, but after three hours of trying to install the first section of hose I was pretty frustrated, especially in the 95 degree weather. No matter how long I had the end of the hose sit in boiling hot water, I could not get it on the holding tank flange. This hose is pretty stiff and in my opinion undersized.
So I finally hit on a method that worked. I bought a 1 1/2 inch diameter nylon coupler--that you would use to connect two hoses. It had a ridge in the center that you could butt the hoses up against.
I cut it in half, on one side of the ridge, then cut the piece with the ridge lengthwise. This I installed, with the ridge on the outside, in the end of hose that I had put in very hot water for 1 minute. Then I put in a tapered thru hull bung, 1 1/4 " at one end and 1 1/2" on the other end, and hammered it in the end of the hose, leaving about 3/4" of the bung exposed. This technique temporarily increased the circumference of the hose about 3/8" or so.(removal of the bung involved a pair of vise-grip pliers clamped on the bung.)I found that if I left it in for 20 minutes, the hose would hold the enlarged size long enough so that I could work the hose onto the fitting with ease. After a couple of minutes after being installed, the hose contracted tight again.
Since the thru hull valve for the head is frozen open, I could not replace that las section of hose yet . Have to do that at the next haulout. I will be leaving the boat closed up a couple of days and when I come back hopefully the smelll will be history.

[sailingdog]

sounds good.

[T37Chef]

Originally Posted by dohenyboy

but after three hours of trying to install the first section of hose I was pretty frustrated, especially in the 95 degree weather. No matter how long I had the end of the hose sit in boiling hot water, I could not get it on the holding tank flange. This hose is pretty stiff and in my opinion undersized.

I just went through the same process (what a shitty job, pun intended) I cant agree more about trying to get the hose on the tank flange, 1 1/2" my ass! I think the entire marina heard me cussing for about three hours! Undersized is being nice!

[justified]

You should switch #2and #3 and add in a lockout Y valve so you can change from your handpump overboard or to your deck pumpout. Some harbors will require you to put on a lock or pl;astic zip tie on that fitting. why would you want to carry around a half full tank?

[RAGTIMEDON]

A year ago I did the hose replacement and went a couple steps further-- New, larger tank, new head, the only thing reused was the deck pumpout fitting and the vent fitting on the stern. Even with absolutely no smell, it is a shitty job! Why do they sell 3 inch fittings marked 1-1/2????