Sealing hoses as they pass into anchor locker

[patjam]

I've got the standard sailboat holding tank under the vberth installation and am getting ready to replace the holding tank and improve the waste pumpout and vent installation. I am looking for advice on how best to route them through the aft bulkhead of the anchor locker. This will be the second time I've done a major refit of the holding tank since owning the boat and I don't want to have to do it again.

Presently the vent and waste discharge lines lead aft and up through a hanging locker. There are low points in both of them, the vent line is undersized and overly long, and the distaff members of the family complain on hot summer days about the odor near this hanging locker. I've assumed this is due to the poorly implemented and undersized vent in combination with the low points that never drain. And waste lines in the same space as clothes storage just doesn't seem that ideal.

My plan is to make a short 1 inch vent line straight out the bow end of a new holding tank, through the aft bulkhead of the anchor locker, and terminate it with a 1" through hull positioned 8 inches or so below the deck on the topsides. No clamshell, just a wide open Marelon through hull. Less than five feet, less than 45 degree slope, I've read my Peggie Hall posts.

For the discharge line I am also thinking of running it through the anchor locker and up through a new deck pumpout fitting. It will be shorter with no low points and the new holding tank has a dip tube for more complete tank evacuation. So far so good.

Now I am at the nerve wracking part of the project where I am ready to start drilling holes in my boat. I am concerned about the holes in the anchor locker bulkhead and how to properly seal them.

Are there bulkhead fittings made for this purpose? I've searched but am not coming up with much that seems designed for the purpose. Yet I know many here and other places discuss routing vent lines through the anchor locker. How are they sealed? I know the wrong answer is to just caulk them up with silicone. I've read of at least one boat owner wrapping the hoses with butyl tape (I've already got this on hand for sealing the through hull fittings) and friction jamming it into the hole. Seems expedient but I'm not sure it is built for the ages.

I've considered just using a standard deck fill fitting for the waste discharge hose as it passes through the anchor locker bulkhead. This would have a hose barb on the side with the tank, and female threading on the anchor locker side that I could thread a 90 degree elbow onto and then a short section of hose up to the deck pumpout fitting. While this seems to be the best engineered method I've come up with, the space is very tight and the standard deck fitting has a pretty wide diameter. If there is another solution or bulkhead fitting for hose I am interested in checking it out.

What say ye experts? How have you handled routing hoses through your anchor locker in a skookum fashion?

-Pat

 

[Rick I]

If you vent the tank as described your holding tank will fill with sea water every time you encounter a bit of weather. I had a similar vent (actually it was screened) on one of my boats and had to plug it with silicone every time it piped up. Every time the bow digs in water will enter the tank. A clamshell might help a bit.

 

[Ron20324]

IT SEEMS ALL BOATS HAVE THEIR ANCHOR LOCKER DRAIN AT THE BOTTOM. ON MINE, I FOUND OUT QUICKLY THAT IT CAN GATHER DEBRIS AND STOP UP. First haluout, I added a second drain higher than the first one. Properly positioned this way, water can not back up so much and flood into the interior. I suggest you do this no matter how you seal the new hose holes. Rick's concern about taking in water in the vent, put an on-off valve on the vent if you think that would be a problem. Just be sure to open it when using the head! But, yeah, a clamshell would help. My vent is just a thru-hull, but it is high up on the 1/4 and not a concern.

 

[patjam]

Thanks for the responses. I have considered the risk of water coming in when the bow gets buried and am prepared to put a cork in it or install a valve to shut it off when needed. Or alter it later to use a clamshell. I can't think of any other place to install the vent and keep to the short straight vent line that is recommended, and I've read over and over Peggie recommending a plain open mushroom through hull fitting.

 

[Herrick18911]

I would be very reluctant to put 1-1/2" holes in the anchor locker bulkhead. Bury the bow in a wave and you stand a good chance at getting seawater in the cabin or in the bilge. The drain in the locker, if not clogged with debris, is only 1/2" or 5/8" or so and would be inadequate to protect you from such an event.

One consideration for installing a vent line up in the bow: it's upwind if you catch my drift.

We have our vent for the head routed through the stern. There is a charcoal filter installed before the thru-hull fitting so we never smell anything. We just have to be careful to not overfill the tank.

Tod

 

[Peggie Hall HeadMistress]

A Uniseal is the best solution

Now I am at the nerve wracking part of the project where I am ready to start drilling holes in my boat. I am concerned about the holes in the anchor locker bulkhead and how to properly seal them.

Check this out, Pat UNISEAL Uniseal Instructions These gadgets seal so completely, we've used 'em to relocate or add fitting to a waste tank.

As for taking on water via the tank vent, unless you're gonna spend hours with the bow buried, you won't take on enough to notice...simply because there's outbound pressure from the tank "pushing back" against any water that's only splashed or a momentarily submerged bow. Just make sure the thru-hull is high enough to be well above the waterline and far enough forward to stay out of the water even if/when your rails are buried. And as for odor worries...the whole point of venting out the bow is provide a constant source of air into the tank to keep it aerobic, which is the key to odor elimination.

If you'd like to discuss your plan in more detail than is practical in open forum, you're welcome to email me (EMAIL pls, not a PM!).