Jump to content

Through hull fittings


Featured Posts

Hi All,

 

Advise me please, My bathroom sink and shower connections - can they be on a common outflow? I don't want to run the gulper when I am using the sink. I don't want the sink or the shower backing up into the corresponding...I was thinking of joining the sink waste to the waste of the shower - after the gulper, via a Y fitting, but my concern now is that the gulper could potentially pump up to the sink? 

 

Any thoughts  - or, do I fit separate through hull fittings? 

 

Cheers

 

Alistair

Link to comment
Share on other sites

Although you could T the gulper into the sink waste be aware that if by some chance you plugged the hull outlet with say bank mud the gulper will fill the sink and possibly overflow. We occasionally had this on the hire fleet so used two skin fittings.

Link to comment
Share on other sites

+1 for its own dedicated skin fitting. 

 

I admit it's terrifying to go at the hull this close to water with a hole saw, but I didn't sink, honest! 

Link to comment
Share on other sites

1 minute ago, Rumsky said:

+1 for its own dedicated skin fitting. 

 

I admit it's terrifying to go at the hull this close to water with a hole saw, but I didn't sink, honest! 

Triple-check that the hole will be more than 10" above the water line.

Link to comment
Share on other sites

5 minutes ago, WotEver said:

Triple-check that the hole will be more than 10" above the water line.

Probably mandatory for RCD compliance but not mandatory for the BSS. Actually its not mandatory for the RCD as I understand things but ifits lower than 10" above the water line as long as the pipe work inside the boat rises to above the 10 inches. If lower than 10" best practice but probably not vital on an inland boat is to fit a valve on the inside of the skin fitting.

Link to comment
Share on other sites

5 minutes ago, Rumsky said:

+1 for its own dedicated skin fitting. 

 

I admit it's terrifying to go at the hull this close to water with a hole saw, but I didn't sink, honest! 

You think that's close ?

 

The water line is the (what was) the white band between the light blue and the dark blue.

 

 

Inked15-10-19c-Crop.jpg

 

 

 

 

 

Link to comment
Share on other sites

12 minutes ago, WotEver said:

Triple-check that the hole will be more than 10" above the water line.

I couldn't stick to this unfortunately, even using a 90 degree drain straight from the sink the most I could manage above the waterline was about 6" otherwise the water would never have made it out of the boat. 

7 minutes ago, Alan de Enfield said:

You think that's close ?

 

The water line is the (what was) the white band between the light blue and the dark blue.

 

 

Inked15-10-19c-Crop.jpg

 

 

 

 

 

I wouldn't fancy fitting those while it was in the water. 

Link to comment
Share on other sites

12 minutes ago, Tony Brooks said:

Probably mandatory for RCD compliance but not mandatory for the BSS. Actually its not mandatory for the RCD as I understand things but ifits lower than 10" above the water line as long as the pipe work inside the boat rises to above the 10 inches. If lower than 10" best practice but probably not vital on an inland boat is to fit a valve on the inside of the skin fitting.

Yes, but he'll get fed up with an advisory every time he has a BSS ;)

 

I got fed up with being told my weed hatch needed to be 1.5" higher even though that would have made it impossible to access.

 

If it's lower than 10" then I'd suggest double-clips onto the fitting in addition to the rise up.

9 minutes ago, Rumsky said:

I couldn't stick to this unfortunately, even using a 90 degree drain straight from the sink the most I could manage above the waterline was about 6" otherwise the water would never have made it out of the boat. 

Double-clip the hose and ensure it has a rise to above 10" between the sink and the fitting then :)

Link to comment
Share on other sites

21 minutes ago, Rumsky said:

I couldn't stick to this unfortunately, even using a 90 degree drain straight from the sink the most I could manage above the waterline was about 6" otherwise the water would never have made it out of the boat. 

 

 

That is why most 'private' narrowboats can not easily achieve the commercial BSS requirements of 10" without complicated 'swan-neck' piping systems that take the pipe back to above the 10" height and then back down to the skin-fitting.

 

From the BSS :

 

To reduce the risk of your boat sinking if it keels over or is excessively weighed down, it's a good idea for privately owned boats to only have openings which are at a height of at least 250mm (10ins) above the waterline. Where openings are necessary below this level this risk can be reduced by ensuring that these openings are permanently and securely connected to ducts or pipes, which are watertight up to that level.

Self-draining cockpits may not be able to meet the 250mm (10ins) recommendation but, for privately owned boats, it's a good idea to stop water getting into other parts of the hull by incorporating non-return valves in the drains and/or having bulkheads or cills up to a height of 150mm (6ins).

A weed hatch, if not properly secured, can allow water into the bilges of a boat, which could ultimately cause it to sink. It's advisable for privately owned boats to have a secure and watertight weed hatch which reaches to at least 150mm (6ins) above the waterline, when the boat is loaded up as normal. [10.3]

 

From an accident report where a NB sunk on the Thames :

 

On the 24th August 2012 a Narrowboat was delivered by road to South Dock Marina in London for a new owner.  The vessel was lifted into the dock and the new owner requested to lock out of the marina as they had an overnight berth in Limehouse Marina; a short distance up the River Thames.  The vessel departed the lock at 17:00 with 5 adults and 1 dog aboard.  As they departed the lock the lock keeper commented to that they should have lifejackets on board as they appeared to be missing.  The crew decided to continue on and left the lock with 3 adults in the aft cockpit and 2 adults in the cabin.  The vessel transited directly across the river to the starboard side of the channel and then turned upriver towards Limehouse Marina. 
 
Shortly into their transit the crew noted a change in the engine note and opened the engine room hatch to find the engine half submerged.  All persons quickly moved to the stern to try and bail out the engine room, but were unable to cope with the ingress of water into the vessel.  The engine room continued to fill with water and flooded into the main cabin, submerging the aft coaming below the water, resulting in severe flooding of the vessel which sank within 10 seconds.  All of the crew and the dog entered the water without lifejackets, but were rescued by a nearby RIB and Police Launch.

 

Safety Lessons The hull of the vessel had been completely double plated and the increased weight of this plating had resulted in a reduced safety clearance; with the bottom of the engine room vent being positioned approximately 65mm above the waterline.  With 3 persons positioned on the aft deck the bottom of the engine room air vent became submerged beneath the waterline by 50mm, the resulting downflooding and sinking of the vessel was inevitable.  

 

(Three people on the stern made it 'drop' by 115mm) 
 

 

Even if you 'do' the swan neck I'd suggest fitting a sea-cock so that if the pipe comes off or splits then at least you have an instant way of stopping any in-rush.

 

Again from the BSS  (compulsory for commercial boats and recommended for Private' boats.

 

An effective valve or cock fitted in water intake pipes can reduce the risk of the boat sinking if the pipe is damaged in some way. It's a good idea to fit these to all skin hull fittings that are below the water line when the boat is normally loaded, since they allow you to quickly isolate any water intakes. [10.4]

 

Any openings in the hull must be at least 250mm above the normal laden water line. However, if this cannot be achieved for, say, a sink outlet, you should ensure that the outlet pipe within the vessel is watertight to that height inside the vessel. This will achieve the same objective of preventing water seeping into the boat. The pipe joints need to be clipped to remain watertight - push-fit plumbing is not recommended in case it comes apart under pressure. [10.4]
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Edited by Alan de Enfield
Link to comment
Share on other sites

9 minutes ago, Alan de Enfield said:

That is why most 'private' narrowboats can not easily achieve the commercial BSS requirements of 10" without complicated 'swan-neck' piping systems that take the pipe back to above the 10" height and then back down to the skin-fitting.

It ain't really complicated, is it?  From the skin fitting rise it up a bit, then drop back down to the sink outlet.  You've effectively made a trap to boot.

Link to comment
Share on other sites

3 minutes ago, WotEver said:

It ain't really complicated, is it?  From the skin fitting rise it up a bit, then drop back down to the sink outlet.  You've effectively made a trap to boot.

 

Not for normal folks, buy we are not talking about 'normal folks' are we ?

 

My boat has ended up with a Grey water tank and then pumped out every few days. As the sinks are actually virtually on the water line, the water would not run uphill from the sink by 10".

Link to comment
Share on other sites

24 minutes ago, Tracy D'arth said:

As I read the reg, if the waste pipe is continuous and cannot come apart, it is the height of the top of the basin that must be 10" above the water line.

TD'

Just a question - how could a 'continuous pipe' go out of a hull without joints and yet be attached to the hull fitting ?

 

 

If the sink is already more than 10" above the water line it should not be impossible to get the drain pipe to exit at 'about' 10" (it doesn't need much slope to drain water)

Link to comment
Share on other sites

3 minutes ago, Alan de Enfield said:

If the sink is already more than 10" above the water line it should not be impossible to get the drain pipe to exit at 'about' 10" (it doesn't need much slope to drain water)

You missed the top of the basin.

4 minutes ago, Alan de Enfield said:

Just a question - how could a 'continuous pipe' go out of a hull without joints and yet be attached to the hull fitting ?

By being one continuous pipe with no joints that might fall apart?

Link to comment
Share on other sites

18 minutes ago, Alan de Enfield said:

Just a question - how could a 'continuous pipe' go out of a hull without joints and yet be attached to the hull fitting ?

 

 

If the sink is already more than 10" above the water line it should not be impossible to get the drain pipe to exit at 'about' 10" (it doesn't need much slope to drain water)

Of course there are joints, but not push fit. Solvent welded plastic or screwed fittings will comply.

As the whole purpose of the reg is to prevent water entering the boat if heeled, its the top height of the sink or basin that is important as long as the plumbing cannot come apart.

Edited by Tracy D'arth
Link to comment
Share on other sites

2 hours ago, alistair1537 said:

Hi All,

 

Advise me please, My bathroom sink and shower connections - can they be on a common outflow? I don't want to run the gulper when I am using the sink. I don't want the sink or the shower backing up into the corresponding...I was thinking of joining the sink waste to the waste of the shower - after the gulper, via a Y fitting, but my concern now is that the gulper could potentially pump up to the sink? 

 

Any thoughts  - or, do I fit separate through hull fittings? 

 

Cheers

 

Alistair

Mine go through just one, when the pump filter is clean, then I just see the bubbles in the sink waste, I have never had water actually come up. Someone asked the same question on FB and this is the sketch I did of my connections 

Untitled.jpg

Link to comment
Share on other sites

14 minutes ago, ditchcrawler said:

The only mention I can find of waterline in the BSS is for deck drains and gas lockers

Did you look in the hire boat BSS? I think the minimum height used to be in the ordinary BSS but was dropped some years ago. I am sure its in the hire boat BSS.

Link to comment
Share on other sites

13 minutes ago, Tony Brooks said:

Did you look in the hire boat BSS? I think the minimum height used to be in the ordinary BSS but was dropped some years ago. I am sure its in the hire boat BSS.

 

It is in the 2002 BSS that I pasted above.

And the new 2017 (Commercial Boats) BSS states :

 

 

Screenshot (186).png

Screenshot (187).png

Screenshot (188).png

Edited by Alan de Enfield
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.