Need To Make 3" Under Water Pipe Connection

[JoeH]

I need some advice on how to couple two 3" PVC pipes together under 20ft of pond water.

I have an irrigation pond and need to install a new inlet filter after many years. The old filter is simply 200ft of 4" flex tubing as used in septic drain fields just laying on the floor of the pond. It is pretty well stopped up and I want to replace it with a floating filter. to do this, I need to have a diver go down to the point where the 3" PVC comes through the dam, cut off the old pipe and couple a 50ft length of 3" flexible schedule 40 type PVC pipe to the existing rigid schedule 40pvc pipe.

I have looked for recommendations on how to join these two 3" PVC pipes (one flexible and one rigid) but have found no fittings or process on the internet suggesting how to do this. I would appreciate suggestions please.

Thanks

Joe

[txpoolguy]

The swimming pool industry doesn't have much for making submerged glue joints. There are some pvc glues that can work in moist conditions, but not for submerged joints. Perhaps someone else will have a suggestion or perhaps some marine products might be available. BP might have some leftover glue, but I'm not sure you'd want to use it...lol

[Pool Clown]

Forgive me, but i can't figure out if this is a suction pipe or a return or pressure pipe.

[dscriterium]

I think Pool Clown is on the right track......that it is a suction fitting and, as such, will not require the same sturdiness if it were on the pressure side.

They make friction-fit "splicing" fittings that will screw down and seal two sections of rigid PVC.

Glue on a male threaded fitting on the end of the flex and then a female matching fixture on a 1' section of rigid. This will give you a rigid end of the flex which you can then take down and attach to the rigid end protruding from the dam.

Those two rigid ends can then be coupled with the "splicing" or "repair" fitting.

I have used that "repair" fitting on the pressure side of a pool but that may be far less psi (15-20) than your irrigation pump will produce