Head Troubles

[Denis]

I am removing the Jabsco pump style head and installing a new Jabsco electric head. I took out the existing flexible waste line (that was fun) and installed a new 1.5" PVC pipe. I found out why the old head didn't work and why the new one probably will not be much better. The waste line must angle up about ten inches to get into the waste tank. I don't know who came up with that layout but I know for sure it wasn't someone who should understand that %&$# must run downhill. I looked everywhere to see if I could mount the waste tank in another location so that I could mount it below the head, but there is no room now that everything else is installed. The time for that decision should have been before the deck and all the other stuff was installed. This head and waste tank must have been an afterthought!

[RicM]

Granted it's easier to get #@%^ to flow downhill, but when using the head we want the @#$%y gases to stay in the tank rather than flow back up though the bowl, right? The pumps' job is to move the stuff uphill, no?

[Pitou]

There should be a vented loop that goes from the head to the holding tank that prevents the backflow from the tank from what I understand and ther is also a check valve in the head. You can see the vented loop up above the hot water tank.

I have the Jabsco electric head and everything is located as yours I believe / no back-up problems here. Working on the head is never fun / replaced the macerator pump last year .

[Mariner]

What exact model are you replacing the head with? Is it a vacu-flush or just an electric waste pump? Are you replacing just the head, or the tank as well?

[Denis]

It is a Jabsco quiet flush m#37045-0092. I am not changing the holding tank just the lines and head. I really wanted to put in a larger holding tank but there is just no room that I can see. Im almost excited, I can't wait to try it out! Life is full of very simple pleasures.

[DougSea]

It is a Jabsco quiet flush m#37045-0092. I am not changing the holding tank just the lines and head. I really wanted to put in a larger holding tank but there is just no room that I can see. Im almost excited, I can't wait to try it out! Life is full of very simple pleasures.

Did you look into a flexible tank at all? My brother has a Sabre 34 and the hard tank was replaced by the prior owner with a flexible waste tank. Seems like that might address the sizing issue.

I'll be interested to hear how it all "works out"...

[RicM]

I've heard there's only one downside of flex tanks, but it's a big one. When the tank springs a leak, ANY size leak, the whole thing just empties out into your bilge immediately. There are no warning signs, whiffs of unpleasantness, just Ka BOOM!

[Denis]

OMG, picture that!

[TonyAmalfitano]

If you were plumbing your house you would be using a gravity system with 1/4" pitch per foot. Scat does roll downhill. Plumbing a boat is a beast of a different smell. Scat rides in a plug of water pushed by air into the holding tank. That's why we pump a few strokes wet followed several dry pumps. The dry pumps are moving your doings to the tank. Most users of MSD's pump way too much water into the tank filling the tank. Thus they think the tank is only good for a few droppings. Less water, more air (dry) = more use out of the tank.
Over at HunterOwners.com you will find Peggy Hall the "Head Mistress." She has a real fine book on MSD's.

http://www.sailboatowners.com/forums/menunew.tpl?fno=11

A bladder will permeate just like the hose, I know, I had one.