Seacocks and Skin Fittings/Thru Hulls

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asteven221

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I have removed 9 seacocks and thru hulls from my Bav 44 and now need to order the replacements. The small ones have 3/4 marked on the seacocks which are for the sinks, shower, toilet inlets and all are identical. There are also 2 for the heads outlets. These are not marked with any sizes.

As I am buying online I am a bit confused as to how these things are measured. With the smaller seacocks the fact one is marked 3/4 is a clue of course! Where does the 3/4 inch come from? And as long as I order 3/4 inch thru hull, elbow and hose tail all will fit as expected? Non tapered?

With the toilet outlets, they look as if they will be 1.5 inch, but as there are no markings I am making a judgement based on the fittings available and what sizes are definitely not right! Not very scientific I know! Both toilets are Jabsco, one manual and one electric. Is 1.5 inch correct?

I am planning to buy from ASAP using Maestrini fittings, which they sell as "Corrosion Resistant (CR), Dezincification Resistant Brass (DZR)! Does anyone have any experience of these i.e any reason not to go for these fittings?

Thanks. [FONT=&quot] [/FONT]
 
asteven221 said:
I have removed 9 seacocks and thru hulls from my Bav 44 and now need to order the replacements. The small ones have 3/4 marked on the seacocks which are for the sinks, shower, toilet inlets and all are identical. There are also 2 for the heads outlets. These are not marked with any sizes.

As I am buying online I am a bit confused as to how these things are measured. With the smaller seacocks the fact one is marked 3/4 is a clue of course! Where does the 3/4 inch come from? And as long as I order 3/4 inch thru hull, elbow and hose tail all will fit as expected? Non tapered?

With the toilet outlets, they look as if they will be 1.5 inch, but as there are no markings I am making a judgement based on the fittings available and what sizes are definitely not right! Not very scientific I know! Both toilets are Jabsco, one manual and one electric. Is 1.5 inch correct?

I am planning to buy from ASAP using Maestrini fittings, which they sell as "Corrosion Resistant (CR), Dezincification Resistant Brass (DZR)! Does anyone have any experience of these i.e any reason not to go for these fittings?

Thanks. [FONT="] [/FONT]
Click to expand...

It comes originally from the nominal bore of iron pipe, It is also the BSP thread size of the thread that would nave been cut on the outside of the pipe. ( thats why a 3/4 " BSP thread is a lot larger than 3/4" outside diameter, just over 1" in fact)

For your purposes, as far as the valves ( ball valves presumably ) are concerned the sizes quoted are the BSP thread size.

For the hose tails you also have to consider the hose bore as well as the BSP thread size .... they may not necessarily be the same

(1½ " BSP thread is 1.88" OD)
 
Last edited:
asteven221 said:
I am planning to buy from ASAP using Maestrini fittings, which they sell as "Corrosion Resistant (CR), Dezincification Resistant Brass (DZR)! Does anyone have any experience of these i.e any reason not to go for these fittings?

[FONT="] [/FONT][/QUOTE]

I know of no reason NOT to use the ASAP-stocked Maestrini fittings - ASAP are a reliable and helpful organisation - and the pic shown in [URL="http://www.ybw.com/forums/showthread.php?530419-Dezinc-d-through-hulls"]Dezinc-d-through-hulls[/URL] is a good reminder of why one should be very wary of fittings that ain't 'DZR'..... or Marelon, which contain no brass to corrode.

As an aside, it was through publication on this very forum that the scale of the problem was realised and promulgated. Individual surveyors had encountered problems. Yard foremen and marine engineers had encountered the same, here and there. Individual insurance brokers were dimly aware..... but they didn't/don't communicate with each other. It took this place and its contributors to bring a realisation that the problem had become widespread.

This was 'flagged up' to US and Australian yottie magazines. Editors were sceptical at first, as they 'hadn't heard any reports' but after a bit of investigation they agreed and promulgated the concerns to their readers. Of course, after a while, they started telling us they'd discovered the problem..... as is their way. :rolleyes:
Click to expand...
 
asteven221 said:
I have removed 9 seacocks and thru hulls from my Bav 44 and now need to order the replacements. The small ones have 3/4 marked on the seacocks which are for the sinks, shower, toilet inlets and all are identical. There are also 2 for the heads outlets. These are not marked with any sizes.

As I am buying online I am a bit confused as to how these things are measured. With the smaller seacocks the fact one is marked 3/4 is a clue of course! Where does the 3/4 inch come from? And as long as I order 3/4 inch thru hull, elbow and hose tail all will fit as expected? Non tapered?

With the toilet outlets, they look as if they will be 1.5 inch, but as there are no markings I am making a judgement based on the fittings available and what sizes are definitely not right! Not very scientific I know! Both toilets are Jabsco, one manual and one electric. Is 1.5 inch correct?

I am planning to buy from ASAP using Maestrini fittings, which they sell as "Corrosion Resistant (CR), Dezincification Resistant Brass (DZR)! Does anyone have any experience of these i.e any reason not to go for these fittings?

Thanks. [FONT="] [/FONT]
Click to expand...

Nothing wrong with DZRbrass skin fittings, ball valves(make sure they have stainless handles) and hose-tails as long as they are marked as such and from a reliable supplier such as ASAP.

Www.solocoastalsailing.co.uk
 
asteven221 said:
all will fit as expected? Non tapered?
Thanks. [FONT="] [/FONT]
Click to expand...

Hose tails and elbows usually tapered but ballvalve to skin fitting will be both parallel so for the latter order a lock nut of the matching bsp size so after fitting the skin fitting you screw on the lock nut then your ball valve (with your chosen sealant) until the handle is in the best position for access then tighten the lock nut against the ball valve to stop it rotating.

Www.solocoastalsailing.co.uk
 
Thanks a lot for your assistance.

I was aware having read the magazine reports a while ago about thru hulls etc.... which has always been on the back of my mind. As I have only owned this boat for 18 months, with no knowledge of its history regarding seacocks, replacing them will provide peace of mind.

Although plastic offers many attractive features and i can see the benefits, I am still not 100% convinced of their longer term reliability. There are stories about them snapping, which just backs up my instinct about using plastic. Perhaps they really are much better than DZR, but I am happy to stick with the tried & tested this time around.

Incidentally in case it helps others I used the hole saw method of removing the thru hulls c/w all the internal fittings in one go. It was really easy and fast at about two minutes/thru hull.

In case anyone isn't familiar with this method, you hammer a bung into the thru hull hole. Then saw off the excess so you are left with a bung that's flush with the surface of the thru hull. Then very carefully and accurately mark the centre of the bung and drill a pilot hole. So now you have a pilot hole dead centre of the thru hull. For my 3/4inch thru hulls I used a 28mm hole saw. Carefully start drilling the hole checking you are not wandering of centre. Keep checking that you are drilling brass and not GRP! In a short time the outer flange will become loose or drop off, leaving the rest of the thru hull hanging on inside. A tap with a hammer will push the thru hull inside. All you then need to do is go inside, remove the hose, and that's it - job done. I used a 50mm hole saw for the toilet thru hulls.

There is a You Tube video on this method which is where I got my inspiration. Worked very well for me.
 
asteven221 said:
With the toilet outlets, they look as if they will be 1.5 inch, but as there are no markings I am making a judgement based on the fittings available and what sizes are definitely not right! Not very scientific I know! Both toilets are Jabsco, one manual and one electric. Is 1.5 inch correct?
Click to expand...

I would expect the OD of the toilet outlet thru-hulls taken off to be either circa 42mm or 48mm, corresponding to 1 1/4 or 1 1/2 respectively. Any of those sizes would be normal for toilet outlet ball valves. You would need to order 38mm hosetails for the chosen valve size, as the toilet hose will most likely be ID 38mm.
 
Plum said:
Hose tails and elbows usually tapered but ballvalve to skin fitting will be both parallel so for the latter order a lock nut of the matching bsp size so after fitting the skin fitting you screw on the lock nut then your ball valve (with your chosen sealant) until the handle is in the best position for access then tighten the lock nut against the ball valve to stop it rotating.

Www.solocoastalsailing.co.uk
Click to expand...
That's exactly what I did a few weeks ago, with new DZR ball valves from ASAP. I also used the Marstrini brand.
One tip: a problem I have met on my new engine installation is wire reinforced hoses. If they are not a perfect fit to slide onto a hose tail, the wire will hinder a normal hose clip from squeezing the hose to make a good seal. We got around that by carefully pulling the wire out of the last 1 1/4" of hose, with needle nose pliers, which worked very well.
 
Plum said:
Hose tails and elbows usually tapered but ballvalve to skin fitting will be both parallel so for the latter order a lock nut of the matching bsp size so after fitting the skin fitting you screw on the lock nut then your ball valve (with your chosen sealant) until the handle is in the best position for access then tighten the lock nut against the ball valve to stop it rotating.

Www.solocoastalsailing.co.uk
Click to expand...

Thanks Plum, but I am a little confused now! So in case I order the wrong fittings, I would really appreciate your expertise......

You say that the ball valve will be parallel, which is fine. You say that elbows are normally tapered. However on the fittings I removed from the boat the elbow attaches directly on to the ball valve (elbow male & female ball valve). The other end of the elbow is female with the male hose tail attaching direct. So would the elbow be tapered at one one and not the other? Or does it seem like all my fittings are parallel?

Thanks for assisting as all this piping and threads confuse the life out of me! Good tip about using a lock nut as I had not considered that given that none are on the current fittings. What I took out looks as if everything was screwed together using white plumber tape. The thru hulls were sealed with what to looked like hemp in the holes with a rubber gasket on the outside. Clearly worked ok as there were no leaks and they appear to have been there a long time.

Ta
 
Any tips on source of wooden bungs? Clearly for this purpose, and also for emergency purpose, we only need a couple of sizes; I am struggling to find them except in sets of 6-8 where only two are useful.
 
asteven221 said:
Although plastic offers many attractive features and i can see the benefits, I am still not 100% convinced of their longer term reliability. There are stories about them snapping, which just backs up my instinct about using plastic. Perhaps they really are much better than DZR, but I am happy to stick with the tried & tested this time around.
.
Click to expand...

TruDesign are a glass-reinforced nylon composite. I've just fitted a second and, frankly, will not now use anything else. Marelon ones had some previous problems of handles snapping.
 
RJJ said:
Any tips on source of wooden bungs? Clearly for this purpose, and also for emergency purpose, we only need a couple of sizes; I am struggling to find them except in sets of 6-8 where only two are useful.
Click to expand...

As a practical boat owner, I am speechless. Sorry.
 
Pipe threads come in tapered or parallel.

Internal pipe threads in pipe fittings are generally all parallel but external threads can be either parallel or tapered.

A tapered external in a parallel internal thread can be tightened a but more to get the orientation of the fitting correct.

With parallel threads in to parallel threads unless you one to the end (bottom) of the thread it will not lock in that position.

One way is to ue a lock nut the other is to adjust the bottom position by filing/grinding the bottom (locking) position to get the correct( required) orientation. This is the way I prefer but does need a little work/skill.
 
RJJ said:
Any tips on source of wooden bungs? Clearly for this purpose, and also for emergency purpose, we only need a couple of sizes; I am struggling to find them except in sets of 6-8 where only two are useful.
Click to expand...

I had a bag of mixed bungs and only 2 fitted, so I went into the chandlers for some more bags. At £7 a bag I thought sod that, so I got my sanding machine out and sanded them down as required. I found the softwood bungs can be a bit soft and you can easily drift of centre when drilling. I had a brush handle so cut that up for bungs. That was much better as the wood was harder, thus drilling was easier to control. When banging the bungs into the thru hulls it doesn't matter if the bung isn't a perfect circle as long it's in the hole sufficiently so that when you saw the excess off it is close to being a circle. All you need to do is make sure your pilot hole is dead centre of the thru hull hole.
 
Poey50 said:
TruDesign are a glass-reinforced nylon composite. I've just fitted a second and, frankly, will not now use anything else. Marelon ones had some previous problems of handles snapping.
Click to expand...

I had similar comments "why would you trust a plastic through-hull?" when I went for Trudesign. My reply was "well it's a plastic boat". As said, they are glass reinforced so the same as the hull. The only downside I can see is that they are physically larger for the same diameter so you do need a little more space around them.
 
bobgarrett said:
I had similar comments "why would you trust a plastic through-hull?" when I went for Trudesign. My reply was "well it's a plastic boat". As said, they are glass reinforced so the same as the hull. The only downside I can see is that they are physically larger for the same diameter so you do need a little more space around them.
Click to expand...

An upside is that they still move with one finger even after months of being in one position, whereas dzr or bronze can get quite stiff if not regularly used.
 
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