1mm dia. seems a bit small to me - you'd likely get a pool of water inside the fitting as surface tension will almost certainly hold the water back against the small force of gravity - there being no water pressure behind it. I think the recommendation used to be for a drainage hole in conduits systems of at least 3mm - and I'm pretty sure MK recommend 5mm for their masterseal range.


  - Andy.

Make it too small and you will get capillary action or pumping.


Andy B.

Reminds me of the Suez Canal Authority requirements. All ships passing through the Suez Canal require an approved 'Suez Canal Searchlight'. Any ship not having one, or whose searchlight was deemed on inspection not to comply, had to hire a searchlight from the Authority. Among the requirements were two interesting ones:  "The enclosure must be gas-tight" and "The enclosure must be provided with a drain hole at the bottom".

Alasdair

Which makes sense when you consider that much Suez traffic is carrying either oil or more dangerously distillates  or natural gas. Although if the rules are well drafted then I;d expect to see that drain hole /vent in the form of a hose nipple, so that expanding and contracting air can be exchanged to a place outside the hazardous zones for any accumulations of explosive vapours.

Mike,

No need to worry about hazardous vapours as the mounting of the searchlight is right at the prow, forward of any hazardous areas, though to further solve the problem very few tankers (possibly none) are allowed passage through Suez. These two conflicting requirements were seen by us on the ships as a way of guaranteeing that they would be able to hire out the searchlights they had in store as there would always be at least one regulation that was not met.

I thought QuatarGas was shipping via Suez to West Wales ?


Regards


OMS

You are probably right. I have been thinking back, and in my day, which was ... well let's just say it wasn't yesterday, I have sort of dredged up a memory and I think it was that tankers were not allowed through the canal as part of the main convoy. Though in reality gas ships have a very good safety record, much better than oil tankers. The only near miss with a gas ship was one that lost power off the American east coast and drifted for several days, because the crew couldn't get the generators going again. Apparently they tried everything, including by-passing the HV Safety Interlocks......

[Further edit]

I should also have added that the majority of large oil tankers could not go through the canal while full of oil due to their draft. They could only go through when in ballast. Unless they have dredged the canal by a significant amount then this will likely still be the case.

AJJewsbury:

1mm dia. seems a bit small to me - you'd likely get a pool of water inside the fitting as surface tension will almost certainly hold the water back against the small force of gravity - there being no water pressure behind it. I think the recommendation used to be for a drainage hole in conduits systems of at least 3mm - and I'm pretty sure MK recommend 5mm for their masterseal range.


  - Andy.

 

One from this afternoon.

Andy B. 

No fixing screws through the back of the box?


Regards


BOD