Underwater Boat Fittings check

[Coddy]

Hi all

 

A friend of mine recently replaced a seacock fitting to his boat but before doing so he did a bit of investigating as to which he should buy and found this very interesting article.

 

This is a report and findings of a flooding on a charter boat, Random Harvest out of Brighton in July 1999 but has some very good recommendations for all small boat owners.

 

Those of you who have their boat out now or about to do so, I would suggest you give this article a good read and check your craft for possible failure and other suggestions for improvements.

 

Link to article is here http://www.maib.gov.uk/cms_resources.cfm?f...m%20harvest.pdf

 

Poole harbour and I suspect many other harbours where there are a few marinas with electricity supply available may well have similar issues with electrolytic corrosion.

 

Dave

[duncan]

this happened a long time ago, but might help to summarise the relevant bits for this audience -

 

1. battery isolation should be the +ve terminal

2. brass throu hull fittings should be tested annually (arguably avoided on small craft in favour of nylon - my comment not the MAIB)

3. brass fittings should never be subjected to excessive tightening - stresses created can speed up de-zincification/corrosion.

 

general advice on battery positioning, watertight bulkheads and bilge pumps.

 

[shytalk]

nylon skinfittings below the waterline ! a total no no in my opinion the mca dont even allow them below deck level . i tend where possible to use marelon seacocks to solve the possibility of electrolosis problems , the toilet seacocks on most boats are to far from the anode for them to be effectively protected so electricaly bonding them can be counter productive if there is a electrical fault . i recently changed a set of good quality toilet seacocks that had been in place for 12 yrs un bonded which apart from a tinge of pink were still good (judging by the effort needed to remove them )

 

[duncan]

nylon skinfittings below the waterline ! a total no no in my opinion the mca dont even allow them below deck level . i tend where possible to use marelon seacocks to solve the possibility of electrolosis problems , the toilet seacocks on most boats are to far from the anode for them to be effectively protected so electricaly bonding them can be counter productive if there is a electrical fault . i recently changed a set of good quality toilet seacocks that had been in place for 12 yrs un bonded which apart from a tinge of pink were still good (judging by the effort needed to remove them )

thanks for pointing out my lazy choice of words - I agree it was misleading

 

reinforced nylon, such as Marelon, would have been much better.

 

[Graham Nash]

Interesting ....

 

The boat I have in my yard at the moment has a couple of "through the hull" fittings. One looks like a normal 40mm plumbers water pipe, capped off outside (under water) and capped off inside the hull (still below the water line). I have checked both sides and it "seems" to be water tight and looks in good condition. I have not unscrewed the caps on either end (as I dont want to break any seal that may be there). I have no idea what it was for.

 

Would it be better to remove it and fibreglass over the hole ( I would prefer a competent person do that bit if required), leave it as it is or connect a hose on the inside to take it well above the water line just in case the outside cap gives way? (I suppose I could remove the outside cap and connect a pump to this and use it as an input for filling livebait tank or a deck wash system?? or is that as silly an idea as it sounds?)

 

I do not have watertight compartments in the hull, however I have 2 very large automatic bilge pumps and am still to fit a manual pump and my batteries are well above the water line.

[duncan]

Interesting ....

 

(I suppose I could remove the outside cap and connect a pump to this and use it as an input for filling livebait tank or a deck wash system?? or is that as silly an idea as it sounds?)

doesn't sound silly to me, however I would consider replacing whatever it is with a stopcock fitting first ie use the hole but substitute the fitting...

 

you can get them in Marelon

 

then add an appropriate softwood plug to your safety kit onboard and you have the bases covered

[Graham Nash]

Thank you Duncan ... after reading the above article I have looked into getting a bilge alarm (didnt even know they existed) and I will also sort out softwood bungs. I must confess I was struggling with what to do with this "water pipe" sticking through my hull so i now have a plan

[great white]

Graham the alarm is simple

 

If you are fitting an auto bilge pump operated by a float, put in additional wiring so that when the float lifts it also powers up an alarm or light [or both]

 

Easy way to do that is from the switch for the bilge pump, as it is closer to where you want the alarm.

 

Charlie