Odd size tubing

[marchem]

New (to us) 1982 Catalina 27. Waste tank appears to be original Ronco B117. Tank outlet is 1-1/2" metal pipe (with nice green sheen to it), to a metal 1-1/2" tee; one side goes to a pipe elbow reducer, and then to 1.5" ID Shield Exhaust tubing to a manual diaphram pump and finally to a thru hull.

The other leg of the tee connects to 1-7/8" ID Shield Exhaust tubing to a 1-7/8" barbed deck pump out fitting. I have measured several times, and the fitting and tubing are definitely 1-7/8", not 1-1/2".

The vent fitting is a 3/4" MPT to 3/4" barb, with 3/4" ID braided Tygon (PVC) tubing connected to a 1/2" barbed deck vent fitting.

Attached pictures may help visualize.

I'd really like to replace the metal fittings with plastic and all the tubing with Trident 101 and 148. I was thinking of using 5/8" #148 for the vent, replacing the fitting at the tank and using the existing deck vent. I know it's small, but it's a short straight run.

The waste side will be trickier. The screw plate in the deck fitting is frozen (of course), as is the thru hull valve. So there's no way to empty the tank right now. I'm thinking of drilling out the plate, since I've got to replace the deck fitting with a 1-1/2" one anyway. That should let me pump, flush, clean, and empty the tank.

Now coming out of the tank I'll use a 1-1/2" pipe to barb elbow, Trident #101 to a Y valve, Trident #101 to a new 1-1/2" deck pump out, and Trident #101 to the manual pump and thru hull (fixing that at next haul out).

Does that seem reasonable? Any thoughts on brand of Y valve?

Thanks for all the great info and ideas I've seem here so far.

 

[Stu Jackson]

Rob, if anything, I'd INCREASE the size of the vent and put a simple mushroom thru hull fitting on the side of the hull just below the rub rail.

Good luck.

 

[wetass]

Seems reasonable. For the Y-Valve, I like the Forespar Marelon Y-Valves only because I have had 2 of the Jabsco y-valves break off in my hand (Thats a messy job to change out).

The 1-7/8 hose makes sense as that is the standard outer diameter of a 1.5" pipe/nipple. You see it often in exhaust hoses where someone puts the hose directly over the threads of a 1.5" thru-hull.

 

[marchem]

Rob, if anything, I'd INCREASE the size of the vent and put a simple mushroom thru hull fitting on the side of the hull just below the rub rail.

Good luck.

I thought about that, but hate drilling holes, especially in the hull (I'm just now learning about seawater getting into the icebox on the 27!). The hole in the tank is only 3/4" FPT, so I wonder if going to much larger tubing will make much difference?

 

[marchem]

Seems reasonable. For the Y-Valve, I like the Forespar Marelon Y-Valves only because I have had 2 of the Jabsco y-valves break off in my hand (Thats a messy job to change out).

The 1-7/8 hose makes sense as that is the standard outer diameter of a 1.5" pipe/nipple. You see it often in exhaust hoses where someone puts the hose directly over the threads of a 1.5" thru-hull.

That make a lot of sense. So the deck fitting is for 1-1/2" pipe, rather than hose? I sure couldn't find any deck waste fittings for 1-7/8" hose.

 

[caguy]

The only thing I noticed is that I am of the belief that the waste hoses shoule be double clamped.

 

[marchem]

The only thing I noticed is that I am of the belief that the waste hoses shoule be double clamped.

I agree. Not sure which is worse, an open thru hull or dumping the holding tank contents into the bilge.

Although as hard as it is to get the tubing on the fittings hose clamps almost seem redundant.

 

[wetass]

That make a lot of sense. So the deck fitting is for 1-1/2" pipe, rather than hose? I sure couldn't find any deck waste fittings for 1-7/8" hose.

That would be my guess, but from your picture it doesn't actually look like a pipe nipple on the end of that deck plate, but hard to tell. I too have never seen a deck waste fitting MADE for 1-7/8" hose - Heck, not sure that I have ever seen any fitting actually made for 1-7/8" hose....

 

[Fred Villiard]

It might be metric 48mm

Fred Villiard

 

[marchem]

It might be metric 48mm

Fred Villiard

That sure fits but why would Catalina or a PO put in a 48 mm barbed fitting? Does any company make that? I haven't seen it in the catalogs I've looked at.

Unless it's actually for 2" tubing, but I can't imagine that the barb would be less than 2". Still a mystery.

 

[shannon28]

Marchem,

It sounds like an excellent plan. Here are a few ideas for your consideration,

I’d stick with the ¾ “ line, the 5/8” line will be more prone to clogging. The Trident 101 hoses are an excellent choice. However, it looks like the vent hose clamp at the tank fitting is not clamped to the fitting. On the right-hand side of the clamp the hose clearly crimped, and it looks like the same is true on the left-hand side. My guess is that a barbed fitting alone is just too short to easily connect the hose clamp.

Side vented tanks have a basic problem, especially on sailboats. If the tank is near full, any motion or heeling will most likely dump waste into the vent hose, potentially clogging it. You want to have the vent line moving upward as quickly and as continuously as possible so that if this happens the waste will quickly drain out. It appears that your current vent line heads downward for some length. You could use a nipple fitting with a female/female 90 or 45 elbow and add a male barbed fitting to get the vent hose moving upward quickly. The nipple extender will provide better access than a barbed fitting alone.

2. I’m a little confused by your statements and the pictures. Picture one seems the output side of the tank having a PVC barbed fitting with a 1½” hose attached, but you state that tank outlet fitting is a metal pipe. You state that you want to use a 1 ½” barbed elbow coming out of the outlet side of the tank, I’m assuming the hand pump above the tank. While this approach would be excellent, I see a potential problem using a male threaded/barbed elbow. The picture suggests that the wood paneled bulkhead and the floor are too close to the outlet to allow a barbed fitting to spin into the tank. If that’s the case, use the same configuration as the vent hose (nipple to female/female 90 or 45 elbow to a male thread/barbed fitting). The elbow is considerably more compact than the barbed elbow.

3. Mount the Y-valve higher than the top of the tank, especially if it’s a Forespar Y-valve. The Marlon is simply glass filled nylon 6/6 and the 6/6 absorbs tremendous amount of water and can smell pretty bad. Plus any y-valve is an opportunity for a leak, so keep the waste out of it as much as possible.

Good luck and fair winds,

 

[marchem]

Marchem,

It sounds like an excellent plan. Here are a few ideas for your consideration,

I’d stick with the ¾ “ line, the 5/8” line will be more prone to clogging. The Trident 101 hoses are an excellent choice. However, it looks like the vent hose clamp at the tank fitting is not clamped to the fitting. On the right-hand side of the clamp the hose clearly crimped, and it looks like the same is true on the left-hand side. My guess is that a barbed fitting alone is just too short to easily connect the hose clamp.

Side vented tanks have a basic problem, especially on sailboats. If the tank is near full, any motion or heeling will most likely dump waste into the vent hose, potentially clogging it. You want to have the vent line moving upward as quickly and as continuously as possible so that if this happens the waste will quickly drain out. It appears that your current vent line heads downward for some length. You could use a nipple fitting with a female/female 90 or 45 elbow and add a male barbed fitting to get the vent hose moving upward quickly. The nipple extender will provide better access than a barbed fitting alone.

Sorry for the confusion. I should have labelled and oriented the pictures. The first picture is actually the pump out fitting under the deck, showing the 1 7/8" ID waste hose (I removed the clamp). The second picture is the vent fitting at the deck, showing the 3/4" ID Tygon clamped on the 1/2" fitting. Third is the vent fitting at the top of the tank. Fourth is looking down at the side of the tank, showing the outlet and hand pump.

2. I’m a little confused by your statements and the pictures. Picture one seems the output side of the tank having a PVC barbed fitting with a 1½” hose attached, but you state that tank outlet fitting is a metal pipe. You state that you want to use a 1 ½” barbed elbow coming out of the outlet side of the tank, I’m assuming the hand pump above the tank. While this approach would be excellent, I see a potential problem using a male threaded/barbed elbow. The picture suggests that the wood paneled bulkhead and the floor are too close to the outlet to allow a barbed fitting to spin into the tank. If that’s the case, use the same configuration as the vent hose (nipple to female/female 90 or 45 elbow to a male thread/barbed fitting). The elbow is considerably more compact than the barbed elbow.

3. Mount the Y-valve higher than the top of the tank, especially if it’s a Forespar Y-valve. The Marlon is simply glass filled nylon 6/6 and the 6/6 absorbs tremendous amount of water and can smell pretty bad. Plus any y-valve is an opportunity for a leak, so keep the waste out of it as much as possible.

I don't think I can easily put the Y-valve higher than the tank. It's all under the v-berth and there's no place on the hull to mount it. I'm actually thinking of eliminating the Y and just going direct to the deck pump out, since I don't anticipate being away from a pump out station for any length of time. I know that eliminates options, but it sure makes the plumbing simpler. Besides, it would be possible to add later, if I really wanted one.

Thanks for the comments.

 

[marchem]

I found some old plumbing schematics from Catalina for the 27 that showed 1 7/8" ID waste tubing going to the deck fitting, so I'm thinking the fitting was originally installed by Catalina in 1982. That may explain why it won't open!

 

[marchem]

Someone on the Yahoo Catalina 30 forum posted this idea for an adapter to use between the 1-7/8" deck fitting and new 1-1/2" waste tubing:

An easy way to go from the 1-7/8" deck tailpiece to a new 1-1/2" sanitation
hose, is to use a Fernco adapter and pipe fittings - all commonly available and cheap.

(From top to bottom.....)

(OEM) 1-7/8" tailpiece

1-1/2 x 1-1/4" Fernco adapter **

1-1/2 x 1-1/2 insert coupler ***

(new) 1-1/2" hose


** Fernco part # 1056-150/125. (The IDs fit the 1-7/8" tailpiece and an 1-1/2" fitting.)

*** 1-1/2 x 1-1/2 coupler - either the typical gray PVC barbed coupler for
1-1/2" black poly pipe (grind down the barbs so the hose slips on easier), or a Marine East coupler (similar to what Chet posted.) Or easier yet, an 1-1/4" copper sweat coupling will slip inside the 1-1/2" hose and the Fernco, and has a thin wall so flow is not affected.

It might be helpful to put a clamp around the new hose where it exits the hole in the liner in the pushpit/pulpit/lazarette/sail locker -- so that the new
hose is supported and doesn't pull on the deck fitting and couplers.