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[lukehallbland]

Does anyone else who uses these find a fair bit (about 2cm in the bottom of a glass) of water every time they open the sub up? I find I get about the same amount regardless of the time it's been in, from a quick 30 second dunk to 12 hours weighted down. There's no sign of any air leaking out so I'm rather confused as to what's going on.

Any of you guys find this or might I have a problem?

[snowwolflair]

If the rings are undamaged they should not leak.  Check whether your bonding of the rings to the hull or dive tube are sound, remember some adhesives are porus even when they look not to be.

If all else fails do the tissue stuffing trick.  Pack the hull with dry tissue and dunk it untill you start to see a leak point by wet tissue.

[sheerline]

The fact you get the same amount of water in regardless of how long your sub hasbeen in the water suggests it is actually sucking water through a seal or fitting somewhere. Each time you take the sub apart and dry it out, the dive unit goes back together and the whole thing is at ambient temperature. As soon as you plunge it into cold water, the air inside the wtc cools down, contracts and causes a partial vacuum. This drop in pressure causes water to be drawn in through your defective seal/ fitting and since the air contacts by a more or less fixed amount, the same mount of water will be drawn into the unit each time, regardless of duration of immersion.
Sounds like a good contender for a pressure nipple so you can apply a little positive pressure to the wtc, this will not only show up your leak but will prevent water ingress.
Chris

[snowwolflair]

Sounds like a good contender for a pressure nipple so you can apply a little positive pressure to the wtc, this will not only show up your leak but will prevent water ingress.

Yes very good idea, if you have a problem it will bubble.  I use ENGEL tanks inside my pressure hull so have positive pressure inside the hull at almost all times.

Make sure it is a full valve not a one way valve as if the external depth/pressure exceeds the hull it will just let water in.

[sheerline]

Always use the 'screw on' dust cap, this will prevent water ingress should the outside water pressure exceed that of the valve. A tyre valve requires a degree of  pressure before it will open in anycase so it gives you a sporting chance should you leave the dust cap off.

[lukehallbland]

Thanks for the help, I took it out of the bath left it to warm up. There were some small bubbles between the prop shaft and the hull, so this has now had about 2 inches of fast glass poured in there and doesn't leak any more!

Thanks for the help!

Out of interest, Sheerline are you the chap who makes the Akula etc?

[sheerline]

Yup, I am that bloke!

[lukehallbland]

Are you part of the Norwich club?

[sheerline]

To a degree Luke, they made me an honourary member and I like to contribute when time permits but it's a bit short supply just lately. I usually try to get there on sub days though.
Chris

[Turbulent]

To a degree Luke, they made me an honourary member and I like to contribute when time permits but it's a bit short supply just lately. I usually try to get there on sub days though.
Chris

Can you make the Bring & Buy  /  BBQ on sunday Chris?

[sheerline]

Hi Turb, it looks like it is on the cards..  I think it should be ok.

[Subculture]

I see you are in Watford.

A shame you missed the Summer Dive-in, which was just down the road from you in St Albans.

Maybe next year?

Also there are the Autumn Dive-ins scheduled for October and November at Brockwell Lido, perhaps we'll see you there?

[lukehallbland]

Afraid I'm off to Norwich for uni in Sept, but i plan to become a member of their club but if I'm around in Watford next summer I'll see if I can pop in

[sheerline]

Turb, do you know if we will be able to get the cars in the park on sunday, is the gate still useable ?