Low pressure i wtc

[p webster]

Now that I've retired I hope to finish the Type Ix sub. I have read that some people use a tube into the wtc to give it positive pressure when testing for leaks initially.
Can someone give me a bit more detail as in 1) What type of tube- Brass, or flexible tube
2)how do they seal it
I know this sounds pretty simple but I don't want to drill holes in the wtc if it is not necessary or alternatively can anyone suggest another method.

[Ralph --- SSBN 598]

Here is a quick and easy way to do what you are asking about.
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I put a tire Schrader valve in the front end cap.
I take all the rubber off of the valve.
I drill small enough that it requires effort to push the valve in to the cap.
I cover it with silicone and then push it in and let it cure.
I do not use the internal valve piece.
I only use the cap.
I use the ones that have a rubber seal in them.
I do this mainly because I live at 3500 feet and where I go to operate is at less than 500feet elevation.
When I travel I keep the cap off the valve stem.
No pressure build up or vacuum build up.

To test the cylinder for leaks, you put the valve center piece in and then your can pressurize your cylinder.
Doesn't require much.
Just blow on the valve stem by mouth.
Put the cylinder in the water and hold it down for a while.

Here is a photo of my Skipjack front end cap.
Power switch and Schrader valve.
The hole the valve is in, is a hole I put a threaded rod through to spin the PVC to cut the cap.

[salmon]

I use the same solution that Ralph uses, that is with a Schrader valve mounted in the end cap.
another way, I heard about, but can not voucher for, is to put you WTC in a tub of hot water (make sure your end caps do not come off), and as the air inside begins to expand, you might be able to see where a leak was coming from.

[bigdave]

I just keep it simple. KISS
I glue in a short section of 1/8" brass tube into an end cap. Front or rear cap wherever you would like it.
It will only stick out about 3/8".
Now you are good to go.
Normally you will have a short section of silicone fuel tubing with a 1/8" solid brass rod cork in the tubing connected to the tube.
I use about 1/2" of fuel tubing with the brass cork about 3/16".
This plug assembly is pushed over the brass tube to seal it.
To test the cylinder just remove the plug assembly and connect a longer section of fuel line.
Like 1-2 feet. Then lightly blow into the tube to pressurize the cylinder and pinch off the hose. (Clamp or fingers)

I have done it with a schrader valve too and both ways work the same.
This is just a cheap and dirty way to do it and it works just as well. BD

[p webster]

Thanks Guys,
I forgot to mention that the wtc is built into the sub as this is a type IX Engel and as such also incorporates a pressure switch.
I was told today that the pressure switch switches of the dive system if it detects any drop in pressure inside the wtc. Problem solved