unusual skin fittings?

[simonebb]

Hi All,

 

I am trying to install a sink and have two existing skin fittings on my boat that could serve as waste water outlets, however the internal fitting appears to be just a 2" length of standard piece of pipe (no thread) approx size 19mm/ 3/4".

 

Is this normal?

 

Could i use a hose connector

http://www.asap-supplies.com/fittings-valves-strainers/fittings/brass-straight-hose-tail-connector-418053

 

and flexible hose pipe to provide an outlet from the sink? if so is brass or plastic better.

 

Or is there a better way to do this?

 

Thanks in advance

Simone

 

 

[bizzard]

Hi All,

 

I am trying to install a sink and have two existing skin fittings on my boat that could serve as waste water outlets, however the internal fitting appears to be just a 2" length of standard piece of pipe (no thread) approx size 19mm/ 3/4".

 

Is this normal?

 

Could i use a hose connector

http://www.asap-supplies.com/fittings-valves-strainers/fittings/brass-straight-hose-tail-connector-418053

 

and flexible hose pipe to provide an outlet from the sink? if so is brass or plastic better.

 

Or is there a better way to do this?

 

Thanks in advance

Simone

 

 

If you are fitting a hose over onto the 2'' long bit of pipe with no thread on it make sure the end of it is internally chamfered or muck will keep building up on a the flow facing ridge and you'll be forever using the plunger. If there's no chamfer I'd file one.

[Alan de Enfield]

What height above the waterline is the skin fitting ?

Is the 2" length of pipe plastic, brass, copper ???????

 

Is the 2" length of pipe standard 'waste pipe' ? If so maybe you could solvent weld more of the same and connect to your sink.

 

The problem with connecting to a smooth pipe is that when hot water goes down the sink it can soften some plastics, &/or rubber hoses. If you are relying on (say) jubilee clips then it is possible that these can allow the 'softened' pipe to come off the fitting.

If this happens and your fitting is close to the water line then you could have water getting into the boat - potentially enough to sink it.

 

Ideally your hull fitting should be 10" Or more above the water line - some are less but you then have to think of ways of ensuring no water ingress - eg

Is there enough space / height to install a 'swan-neck' into the pipe ?

[simonebb]

If you are fitting a hose over onto the 2'' long bit of pipe with no thread on it make sure the end of it is internally chamfered or muck will keep building up on a the flow facing ridge and you'll be forever using the plunger. If there's no chamfer I'd file one.

Thanks Bizzard will do.

presumably i could safely attach the hose with a jubilee clip?

[Alan de Enfield]

Thanks Bizzard will do.

presumably i could safely attach the hose with a jubilee clip?

 

If there is no other way then use 'double' clips (ie two x jubilee clips) to minimise the chance of the hose coming off - I think because of the risk there is something I the BSS about 'double clipping'

 

Edit : I cannot see anything in the latest BSS about 'double clipping' but I'm sure it was mentioned to me during a BSS inspection.

Edited March 26, 2016 by Alan de Enfield

[simonebb]

What height above the waterline is the skin fitting ?

Is the 2" length of pipe plastic, brass, copper ???????

 

Is the 2" length of pipe standard 'waste pipe' ? If so maybe you could solvent weld more of the same and connect to your sink.

 

The problem with connecting to a smooth pipe is that when hot water goes down the sink it can soften some plastics, &/or rubber hoses. If you are relying on (say) jubilee clips then it is possible that these can allow the 'softened' pipe to come off the fitting.

If this happens and your fitting is close to the water line then you could have water getting into the boat - potentially enough to sink it.

 

Ideally your hull fitting should be 10" Or more above the water line - some are less but you then have to think of ways of ensuring no water ingress - eg

Is there enough space / height to install a 'swan-neck' into the pipe ?

The pipe is copper, the skin fitting is 10" above the waterline BUT the boat is currently moored on a tidal river and at high tide on a rough day the waves breach the pipe (both outlets currently have rubber bungs in them)

I am not sure about the swan neck will have to double check height of sink outlet but presumably this would prevent water ingress - assuming hoses havent fallen off!

[simonebb]

 

If there is no other way then use 'double' clips (ie two x jubilee clips) to minimise the chance of the hose coming off - I think because of the risk there is something I the BSS about 'double clipping'

 

Edit : I cannot see anything in the latest BSS about 'double clipping' but I'm sure it was mentioned to me during a BSS inspection.

Hi Alan do you know of any alternatives to jubilee clips, I will certaily go for double clipping but even that doesn't fill me with confidence

[Alan de Enfield]

The pipe is copper, the skin fitting is 10" above the waterline BUT the boat is currently moored on a tidal river and at high tide on a rough day the waves breach the pipe (both outlets currently have rubber bungs in them)

I am not sure about the swan neck will have to double check height of sink outlet but presumably this would prevent water ingress - assuming hoses havent fallen off!

 

Can you not get a copper fitting (plumbers) and solder / compression fitting attached to the end of the pipe length which can then act as an adapter for connection to your sink ?

 

If you cannot get enough height for a swan-neck then consider a one-way valve in the pipe. As with any obstruction it will lead to the increased chance of a blockage but, everything has upsides and downsides, and you will just have to make sure that you flush plenty of water down with the odd bits of potato peelings etc.

[Alan de Enfield]

If the pipe length is 19mm (3/4") OD then you can get a 3/4" to 22mm copper adapter (a 3/4" compression cone in a 22mm compression fitting). This can then be fitted onto your existing 2" pipe length and you then have modern., standard 22mm pipe fittings so you can start to do a 'solid' plumbing job.

 

I would just suggest that 3/4" is very small for a waste pipe and that most modern waste pipes would be 1 1/2" or 38mm. It may be prudent to avoid a 'bodge' and do the job correctly (right sized piping) and start with a new hull fitting. It probably won't cost a great deal more and you will be confident of a safe and secure (blockage fee) water tight job.

[simonebb]

 

Can you not get a copper fitting (plumbers) and solder / compression fitting attached to the end of the pipe length which can then act as an adapter for connection to your sink ?

 

If you cannot get enough height for a swan-neck then consider a one-way valve in the pipe. As with any obstruction it will lead to the increased chance of a blockage but, everything has upsides and downsides, and you will just have to make sure that you flush plenty of water down with the odd bits of potato peelings etc.

I bought a 22mm brass pushfit fitting but its too big and as far as I am aware they are not available in 3/4"? because the pipe has to be accessed through a hole in the cladding and has spray foam insulation there is very little room even if i could find the right size copper or compression fitting, my plumber is a bit baffled and has left it to me to find a solution...

If the pipe length is 19mm (3/4") OD then you can get a 3/4" to 22mm copper adapter (a 3/4" compression cone in a 22mm compression fitting). This can then be fitted onto your existing 2" pipe length and you then have modern., standard 22mm pipe fittings so you can start to do a 'solid' plumbing job.

 

I would just suggest that 3/4" is very small for a waste pipe and that most modern waste pipes would be 1 1/2" or 38mm. It may be prudent to avoid a 'bodge' and do the job correctly (right sized piping) and start with a new hull fitting. It probably won't cost a great deal more and you will be confident of a safe and secure (blockage fee) water tight job.

Yes I am beginning to think this is probably the way to go, new hull fitting, fit for purpose

thanks Alan

[ditchcrawler]

This talk of swan necks and check valves, If this is a motor boat, not a yacht that heals over what are the chances of the water coming in the hole, up the pipe, filling the sink and over topping?

If the pipe falls off the fitting all the swan necks and check valves in the world wont help.

[bizzard]

A simple flexible rubber flap valve (a slice of rubber hot water bottle for example) could be fixed over the outlet on the outside to stop seas rushing in.

[dor]

M y surveyor suggested that double stainless steel jubilee clips over reinforced hose (the sort with helical 'string' in it) would satisfy the RCD. Even if the outlet was less than 10 inches aobve the water line, by doing this the top of the sink effectively became the height above the waterline. Don't fit traps and don't use solvent welding. The latter can cause the joint to crack if the pipe is knocked, whereas pushfits will withstand a little bit of movement.

[adrianh]

The alternative to a jubilee clip is a bolted band clip - search for Mikalor sc37-44ss for example.

If your pipe is 3/4" od copper then you can still get brass compression fittings suitable for air systems - try commercial vehicle spares suppliers, although when I had a small bore system it blocked very easily.

[bizzard]

I would smear something like super glue or Araldite over the fitting and inside the hose entry before slipping it on and clipping it up.

[Bee]

A jubilee clip (or two) is probably absolutely fine but if you really are a bit concerned then you can just buy a proper skin fitting with all the necessary bits and pieces and start from scratch.

[ditchcrawler]

A jubilee clip (or two) is probably absolutely fine but if you really are a bit concerned then you can just buy a proper skin fitting with all the necessary bits and pieces and start from scratch.

It shouldn't be under more than a few inches water gauge pressure so I can't see it blowing off provided its not under strain when you install it.

[BruceinSanity]

I would smear something like super glue or Araldite over the fitting and inside the hose entry before slipping it on and clipping it up.

Or Sikaflex...