Advice on cutting a hole here?

[SFS]

So I will be buying my fitting and my hose from West Marine in Biloxi. Is there a recommended marine sealing material that I can get while I'm there?

I would use butyl tape, which you can buy from MaineSail, a poster here. Look at the picture in Bob's post above. That gray material forming a "cone" around the top threads of the fitting is butyl tape. It will remain flexible and working for years, if not decades, and you can always remove the fitting anytime without a hassle. Don't use a silicone caulk, it leaves a residue that is hard/very hard to remove. Here is a link to a MaineSail thread on how to bed things with butyl:

http://forums.sailboatowners.com/in...-deck-hardware-with-bed-it-butyl-tape.117172/

And a link to how to buy butyl from MaineSail:
http://www.pbase.com/mainecruising/butyl_tape

The tape he sells is high quality, and is used by a LOT of folks on this site.

One more thing. Do a little more research so that you buy the right kind of hose. Search here, or send Peggie Hall a private message. You want a hose that will not be permeable to odor, even for a vent line. That used to mean only one very specific hose that Peggie recommended, but in the past few months she has posted that a new hose is also as good, by a different manufacturer. I can't remember the details, and don't have time to do the search right now.

 

[JosefR]

I probably would, but I need it for Friday and I'm leaving for Gulfport Thursday evening. If there's no good alternative, I have to put this project off until next month.

 

[SFS]

Found it, at least partially. Here is a quote that will get you close:
"And I'd spend the money for Trident 101 or Raritan Saniflex...."

Still looking for a slightly longer discussion.

 

[SFS]

Hold on, here is more:

"It's not necessarily true that all flexible hoses eventually permeate.... That used to be true, and most still do, but not all. Trident 101/102 have been on the market for more than 15 years without a single reported odor permeation failure...and Shields has just introduced a new hose--their Poly X--that they put a lifetime warranty on--and for their price/ft, it better last that long!"

Better send her a private message, but at least you don't have to search the forums. And it may be that she feels you don't need this level of hose for a vent, but she will tell you.

 

[Bob S]

To clarify Bob, you drilled from the outside in, so that fraying at the end of your hole is inside the boat. Right?

No, I drilled from the inside. I taped both inside and out. Hole saws have a pilot. I measured carefully and drilled the pilot hole first to see where I was. If you look at image 878 that is the outer hull. The center of the through hull is about 2" below the rub rail. I measured 3" below the deck to hull screws in the first picture. I'm happy with the results. We are lucky to have Peggie and so many others on this site. I think it's the best site on the internet

 

[Bob S]

I also drilled into the holding tank as close as possible to it's deepest point. Don't want to clog the vent when the tank is half full.

 

[JosefR]

I don't understand what you are referring to here. Why did you drill into the holding tank? And what does its deepest point mean? It's a rectangle. It should be the same depth at all points. And what would it matter anyway?

 

[Bob S]

You are probably right but it is angled on the bottom and the furthest point forward has the widest beam. I think when we are in motion it will be the deepest by volume point. I;m not sure if my thinking is correct but it is my reasoning in cutting into the holding tank there. I used a 1" Uniseal per Peggie's recommendation. The existing vent fitting is too small. I used a pipe plug to seal the old vent. I thought of leaving it as a second vent but the material Catalina used permeates odors.

 

[JosefR]

I wasn't aware I needed to make a new fitting on the tank. That changes everything, now I need to research how to make a 1" fitting attach to the tank.

 

[Bob S]

Peggie gave you the link in your previous thread
http://www.aussieglobe.com/

I don't remember sizes but the hose ID has to fit your bulkhead fitting and the PVC pipe used in the holding tank. The Uniseal was very easy to install. You will need a little Dawn to help slide the hose over the piece of PVC. I had to angle it as you can see to not interfere with the settee cover. Take your time and think it out. It really is worth it and not difficult at all.

 

[JosefR]

Yeah, I saw that link and I have no idea which product in that catalog you are referring to. If I actually order whichever product it is that you are saying that I need, I will have to wait until the middle of October to do this project instead of tomorrow.

I just realized that you guys are saying this seal is supposed to go on the tank, since the picture of the tank just appeared yesterday for the first time...I thought you were putting it on the thru Hull fitting.

I can't imagine how this thing holds a fitting in place without threading a hole in the tank. I just watched a video of it and I see how it works but it doesn't seem very secure. Plus it requires a PVC pipe to go into the tank quite a ways so it doesn't pull out, so I see what you meant by the deep end. This will be a problem as the tank fills, however, as the pipe will becomes submerged and will no longer vent.

 

[JosefR]

Well, it's official. Nobody on the entire Gulf Coast sells this product, so all I can do is order one and wait until my next weekend off in October to install it.

 

[Bob S]

Believe me it's secure. You'll need something to help you slide the hose over the PVC like Dawn or KY. It was the hardest part.I saw your posts in Plumbing. I bought two different sizes of Uniseals because I wasn't sure what one I needed.It was still cheaper than the shipping costs. Take your time! Make sure you dry fit everything before you cut.I used a 45° elbow and cemented two pieces of PVC pipe to it. It gave me just enough bend to not interfere with the cover. I think Peggie frowns on 90° bends.It also helped pushing the pipe into the Uniseal.Gives you something to hold onto.

 

[JosefR]

The part that I find questionable insecurity is the actual PVC going through the uniseal. We're trusting 20 gallons of sewage to a plastic pipe shoved through a rubber hole.

Anyway, I ordered myself a 1 inch uniseal and paid for overnight shipping so I should have it tomorrow. We will find out.

 

[Peggie Hall HeadMistress]

Josef, I don't think you understand how all this works well enough for it be wise for you try to do this product by yourself. Example: "We're trusting 20 gallons of sewage to a plastic pipe shoved through a rubber hose." Not what we're doing at all...you're installing a VENT line...nothing but AIR should go through it. And it's not a rubber hose, it's a rubber grommet. SeaLand Technology uses Uniseals in their diptube replacement discharge fitting kit. It's used a many applications. It's absolutely essential that the hole in the tank be exactly the righ size and perfectly round..."close enough for gov't work" isn't good enough. It's also absolutely essential that the hose put NO side-side stress/pull on the piece of pipe in the Uniseal...that's the only thing that can cause it to leak. The pipe doesn't have to go very far into the tank...in fact, if it's too long waste will rise into it as the tank fills and block it...new flushes will shoot waste out the vent! It should only extend an inch, maybe 2" into the tank, with enough above the tank to put a hose onto it and double clamp it.

Done right, it's great...but messing it up could be a disaster! So please get some help from someone who understands it a bit better than you do...if it weren't an 8 hour drive each way , I'd come down there and help you myself!

 

[JosefR]

I understand it fine. My phone wrote hose, I intended it to say rubber hole not rubber hose.

 

[The Garbone]

I put in a stainless flush mount vent at nearly the same location accessed thru the head cabinet.

 

[Justin_NSA]

What's a rubber hole?? A hole in rubber?

 

[JosefR]

Take a piece of rubber and cut a hole in it. I bet you know what I meant though.

 

[Justin_NSA]

I've never heard of UniSeal before. Clever item in the right places.