Sewage pipe

[essexboy]

With decent flexible sewage pipe now costing a Kidney per metre, why not use rigid plastic ? Is ever used ?

 

[salar]

The reason rigid things tend to be avoided in boats is that boats flex, and if you put a rigid pipe in a bendy boat it may crack. If that pipe is connected to the sea it could sink the boat. If the pipe is full of liquid poo you might wish your boat had sunk. Large bore sewage tubing is expensive but if it keeps the sea out it is worth every penny.

 

[David2452]

With decent flexible sewage pipe now costing a Kidney per metre, why not use rigid plastic ? Is ever used ?

It already is and has been for years, but on larger vessels, I have found a very good method of joining the 38mm bore flexi stuff to 40mmm OD soil pipe. The soil pipe is only used for longer dead straigh runs where it can be easily supported in lined Munson rings.

 

[andy59]

I didn`t think it was that expensive from these guys , no connection . http://www.hyphose.co.uk/112--white-255-p.asp

 

[aquapower]

I didn`t think it was that expensive from these guys , no connection . http://www.hyphose.co.uk/112--white-255-p.asp

That pipe is not good, it will leave nasty smell in the bilges. Use a rubber sanitation hose, usually about £20 a metre but worth every penny.

 

[Deleted User YDKXO]

With decent flexible sewage pipe now costing a Kidney per metre, why not use rigid plastic ? Is ever used ?

Its expensive because it does bend and its also resistant to the toxins in sewage and the chemicals in toilet cleaner which means that it doesn't become porous, like other types of pipe, causing odours to waft permanently through your boat. Its a false economy to use anything else

 

[andy59]

That pipe is not good, it will leave nasty smell in the bilges. Use a rubber sanitation hose, usually about £20 a metre but worth every penny.

Understood , but had it in the boat ( now sold ) for 3 years without any smells . The old blue stuff it replaced was 12 years old and that did whiff a bit .

 

[jfm]

I'm with David 2452. Rigid grey PVC as used in houses is fine in my book. Obviously 1.5 inch not 4 inch, because the waste has been macerated. It is smell free, as proven in houses. You can fit long straight lengths where sutable, then have some flexi sections as needed. I haven't seen a great system for connecting the rigid to the flexi but I'm pleased to see David 2452 has solved that. Can you post some quick details david? Heat gun and 3 jubilee clips? I prefer to use butyl rubber for the flexi sections not the white plastic, and the heat gun isn't as effective on the butyl rubber, maybe.

 

[essexboy]

Thanks for the replies, I have 2 fairly long straight runs so. I think I will look into rigid pipe for those. I shall be interested on David 2452 reply on his joining method.

 

[petem]

There's still some flex in rigid pipe isn't there - surely enough to allow for the flexing of a hull?

 

[David2452]

OK, Here's what I do, quite simple really. You need a decent heat gun to do it , warm up the 40mm OD plastic pipe just enough to allow it to expand as you force in a 1 ½" to 1 ½" nylon hose joiner (I use ones with barbs from Aquafax) Then put a decent hose clamp over it and join the flexi as you would normally to the other end of the joining piece. You can substitute 38mm joiner if using 38mm hose. I have used this method on multi heads installs with up to around 40' runs to the holding tank and it has always worked well with no leakage.

 

[David2452]

There's still some flex in rigid pipe isn't there - surely enough to allow for the flexing of a hull?

Indeed there is.

 

[davids0865]

I once looked at a 58ft motorboat where the seller had fitted 2 domestic toilets complete with 4" pipe to a holding tank with a macerator, he claimed it worked fine...........................:disgust:

 

[jfm]

OK, Here's what I do, quite simple really. You need a decent heat gun to do it , warm up the 40mm OD plastic pipe just enough to allow it to expand as you force in a 1 ½" to 1 ½" nylon hose joiner (I use ones with barbs from Aquafax) Then put a decent hose clamp over it and join the flexi as you would normally to the other end of the joining piece. You can substitute 38mm joiner if using 38mm hose. I have used this method on multi heads installs with up to around 40' runs to the holding tank and it has always worked well with no leakage.

Thanks, sounds good. Call me a worrier but I think I might use some sika292/3M 5200 where the barbed thing is pushed into the rigid plastic pipe

 

[David2452]

Thanks, sounds good. Call me a worrier but I think I might use some sika292/3M 5200 where the barbed thing is pushed into the rigid plastic pipe

I think it's way too tight a fit for that, it would just shove it out of the way, I did at one time consider using solvent weld cement but as I have never had even a weep I don't bother.

 

[PCUK]

I'm using it for the filler to the water tank as in long sections it is far neater and then flexible tube for connection to the tank and deck filler.

 

[Montemar]

It seems there is a difference between white waste hose which is cheaper than sanitation hose which is the aforementioned kidney. I note that Hyphose appear to call their hose "sanitation" hose which Aquafax and ASAP supplies would call waste hose. The extra cost must be for the obviously much higher spec. - not to be sniffed at however....

 

[PCUK]

The proper sanitation hose can be formed into amazingly tight bends which often makes installation a great deal easier.