Aligning plumbing fitttings

[Wanderlust]

I am about to haul my boat and replace many of the skin fittings and valves and I want to ensure the new valves are nicely aligned.

So, if I install a skin fitting and separate ball valve, how do I get the valve handle in the correct position. For example if I tighten the valve onto the skin fitting, but the valve handle is in an awkward position how can I change it? If I unscrew it a bit so the alignment is correct, it will no longer be secure.

I can image fixing this rather inconveniently when doing skin fittings at the same time as valves, by rotating the skin fittings as needed before the sealant cures. But what about where the skin fitting is not being changed? I also have 90 degree elbows to be fitted to the inboard side of some valves, and if some point the wrong way it would be a real pain.

So for a BSP threaded fitting, what do I do if the position is wrong when the fittings are tightened?

[nigel1]

I would have thought that plenty of glop (sealant) on the threads, then back of the valve a touch until the handle is where you want it. The joint is not under a lot of pressure.

A test would be to install the fittings, fix hose to the valve, elevate the hose and fill with water and look for any leaks.

[goboatingnow]

Because the through hull is parallel threaded it never mates properly anyway with the valve. I use 'gas tape' to seal the threads and this allows you to position the handle as you like, you should not "bottom" out the fitting anyway as this adds nothing to the water tightness

Dave

[Wanderlust]

Thanks, but I'm still not comfortable with it.

Let's assume I bottom the thread, and then need to rotate back say 180-270 degrees to get it aligned correctly. I can imagine struggling to remove a tight hose or some other job months later, and find the valve moves, breaking the cured sealant joint. Isn't it likely that such movement will open the joint enough to leak?

Wouldn't the same apply with tape?

[sww914]

You assemble the parts before you install the through hulls.
Put the through hull in a vise with soft jaws so you don't damage it, tighten the valve onto it, and mark the handle location on the inside end of the through hull.
Now take it apart and dry install the through hull. Check it on the inside of the boat and rotate it until the handle will sit where you want it. Go back outside and mark the through hull with an arrow or line pointing up.
Now it's safe to goop it and install it and as long as you tighten it close to the same amount as you did in the vise it will line up.
I actually turn my alignment line a tiny bit clockwise (viewed from the outside) as I install it to compensate for thread deformation from the first tightening.

[nigel1]

I have found that after a few months, the threaded joint becomes pretty tight anyway.
If your uncertain, just ask the fitters at the boat yard how they do it.

[s/v Jedi]

Did you check out MainSail's pages about this? For best results, use a Groco thru-hull fitting into a flanged adapter plate. This secures the important part in an indestructable manner. Plus it gives you a standard NPT thread to work with. The Groco valves are a top choice to mount on that, or a bronze fleet elbow.

With NPT you don't bottom out, you just jam the threads. Dry fit to see how many turns you can fit, then decide on the position you want the fitting. If you need to turn it back a lot, you put more tape on it. The amount is a matter of trial and error. You are correct not to reverse it when using tape.

With other thread sealants, some set up hard to fix it in that position, but you might not be able to take it off anymore. Permatex #1 is one such hard setting sealants.

[HopCar]

Why don't you save yourself the problem and just do the project right to begin with. Screwing a ball valve onto a skin fitting is just a bad idea in several ways.
Use a proper flanged sea cock it's much stronger and you can align it any way you want.

Link: Groco Full-Flow Flanged Ball-Type Seacocks FBV750-2000

Jedi's suggestion to use a Groco Flanged Adapter is good as well.

Groco Flanged Adapter IBVF

[model 10]

I think it was just covered here, pro's use 4200. Try not to turn the valve to far past where you want the handle to be. Don't wory about 90deg of adjustment, the 4200 will take care of that in a NPT fitting

[goboatingnow]

Did you check out MainSail's pages about this? For best results, use a Groco thru-hull fitting into a flanged adapter plate. This secures the important part in an indestructable manner. Plus it gives you a standard NPT thread to work with. The Groco valves are a top choice to mount on that, or a bronze fleet elbow.

Why don't you save yourself the problem and just do the project right to begin with. Screwing a ball valve onto a skin fitting is just a bad idea in several ways.
Use a proper flanged sea cock it's much stronger and you can align it any way you want.

Not to reignite this debate, but Mainesails static pulls show that the 'seacock' fails at the thread junction, since the flanged though hull , in reality is the same as a well supported 'conventiuonal' through hull , I fail to see teh advantage.

Yes a proper seacock in a unibody arrangement is superior, but I doubt there is much difference between the Groco flanged 'through hull' and 'conventional 'through hulls'

Nor do I see "you can align it any way you want." is any different from the issue the OP is having.

Any since the flange adaptor has internal parallel threads ( cause it has too) , you still have the same issue of sealing a parallel to parallel thread.

dave

[donradcliffe]

Its interesting to see the various responses to the OP from BSP land and NPT land. He wouldn't have his problem and be asking the question if he was in NPT land, but I think OZ is not. Actually, the skin fitting is BSP, and most of us ignore the niceties and screw on an NPT ball valve. Even half of a tapered thread is enough to get the joint tight right where you want it. If you are in BSP land, good luck to you!

As a side note, I notice in some of the former British territories they use some sort of cotton string to seal the BSB joints.

[Cheechako]

Originally Posted by goboatingnow

Not to reignite this debate, but Mainesails static pulls show that the 'seacock' fails at the thread junction, since the flanged though hull , in reality is the same as a well supported 'conventiuonal' through hull , I fail to see teh advantage.

Yes a proper seacock in a unibody arrangement is superior, but I doubt there is much difference between the Groco flanged 'through hull' and 'conventional 'through hulls'

Nor do I see "you can align it any way you want." is any different from the issue the OP is having.

Any since the flange adaptor has internal parallel threads ( cause it has too) , you still have the same issue of sealing a parallel to parallel thread.

dave

I'm not sure what yo mean by "conventional thru hull", but any seacock with a flange, even if not bolted, has more resistance to bending pressure on the threads. The flange itself acts as a gusset to support the assembly. A ball valve simply screwed onto a thru hull fitting above the nut puts direct pressure on the threads with a side load.

[HopCar]

"but I doubt there is much difference between the Groco flanged 'through hull' and 'conventional 'through hulls' "
When you screw a ball valve onto a thru-hull you are forcing a tapered female thread onto a straight thread. Not enough threads engage to make a strong joint. The Groco flanged Adapter and Flanged Seacocks allow straight to straight and tapered to tapered thread joints. This is physically much stronger.

"Any since the flange adaptor has internal parallel threads ( cause it has too) , you still have the same issue of sealing a parallel to parallel thread."

With a Flanged Adapter or a Flanged Seacock you don't even need to seal the threads though most people do. The flange is sealed to the hull. You could remove the thru-hull and no water would enter the boat.

I know of at least one bronze thru-hull with a ball valve screwed onto it that broke. The owner of the boat got very excited and claims the boat almost sank. I'm sure everyone here would have a tapered wood plug tied to the thru-hull but this guy didn't.

[goboatingnow]

Originally Posted by Cheechako

I'm not sure what yo mean by "conventional thru hull", but any seacock with a flange, even if not bolted, has more resistance to bending pressure on the threads. The flange itself acts as a gusset to support the assembly. A ball valve simply screwed onto a thru hull fitting above the nut puts direct pressure on the threads with a side load.

A proper unibody seacock is of course better, but the Groco flange adaptor which solved the NPS to NPT issue with threads, in my view doesnt add any appreciable additional strength. You clearly still have a threaded tube exiting the flange to take the ball valve and Maine sails video show the interface that the failure occurs in, is that thread area ( which is self explanatory as thats where the weak point is).

A properly support thru hull, with significant bearing face height and where the valve is close to the flange nut ( ie reducing the lever moment) is likely to be more then sufficiently strong in comparison.

What the Groco adaptor does ( which is why its called an adaptor) is to handle the issue of parallel to taper threads issue , that is a problem ( well sort of ) with parallel through hulls and parallel threaded valves.

dave

[goboatingnow]

When you screw a ball valve onto a thru-hull you are forcing a tapered female thread onto a straight thread. Not enough threads engage to make a strong joint. The Groco flanged Adapter and Flanged Seacocks allow straight to straight and tapered to tapered thread joints. This is physically much stronger.

Over this side of the pond, the valve and the thru hull are both BSP, hence its a parallel to parallel fitting, hence the engaged threads issue dont arise, ( sealing it does). I would always hesitate to connect any male parallel thread to a female taper, bad practice.

Dave