Installing Through-hulls & Repacking A Stuffing Box

[Lighthouse]

Really good photo essays:

"Replacing Through-Hulls"

http://www.pbase.com/mainecruising/replacing_thruhulls

"Repacking a traditional stuffing box"

http://www.pbase.com/mainecruising/stuffing_box

[haffiman37]

I really hope ie did not forget to coat the raw laminate with top-coat/epoxi before assembly!!

[MMNETSEA]

Originally Posted by haffiman37

I really hope ie did not forget to coat the raw laminate with top-coat/epoxi before assembly!!

Please explain what you are suggesting in this comment ? not sure whether this is a question or a statement.

Better still if you return to the website , there is provision for you to make a suggestion at the appropriate stage of assembly of the through-hull and seacock - page 2 deals specifically with this stage and invites comments. By doing that others may find your input useful when they perform similar operations.

[haffiman37]

I have too often come across loose through hulls on older boats, and cases where laminates have been dammaged by water in the area due to no coating of the holes after drilling. People spend thousands on osmosis repairs and epoxi coating of the bottoms, but too often forgets the small details when doing things like this. There is a mentioning of 'gelcoat' in the last sentence, but not quite sure what he means.

Looking at the atachment of the backing plate on the inside, he seems to have used Plastic-Padding with fiber or similar, but I see no traces of removing the top coat before doing it. If so it will create a perfect situation for 'capilar leakage' after some time as Plastic Padding does not bond to top coat.

There is no mentioning of type of sealant to be used, which is another thing. Personally I preferr the Sikaflex products for this kind of jubs, but it is important to use the right type and PRIME all metal parts with acid primer before applying sealant to be sure the Sikaflex/sealant bonds to the material.

Another tip when ataching metal components on fiberglass (port holes, through hulls, stachions.....) using sealant like silicone/Sicaflex is never to fully tighten at install. Leave a 'gap' of 2-3 mm, let dry out 24-48 hours and then tighten. That way one avoids that the metal part cuts through the sealant and gets in direct contact with the fiberglass/gelcoat .

It is the small details that does it in the long run.

[MMNETSEA]

Originally Posted by haffiman37

There is no mentioning of type of sealant to be used, which is another thing. Personally I preferr the Sikaflex products for this kind of jubs, but it is important to use the right type and PRIME all metal parts with acid primer before applying sealant to be sure the Sikaflex/sealant bonds to the material.

As previously suggested reference to the original website's excellent description found in :-

http://www.pbase.com/mainecruising/replacing_thruhulls

The mention of the sealants is clearly provided :-

1. See the chapter on page 2 , 7th June "Flange Adapter with Bronze Ball Valve ready to Install" carries all the details of the sealants used in this procedure.

2. See also the final chapter on page 2 "External View of installed Through-Hull"

A careful read should reveal that most of your useful comments have already been covered.

[haffiman37]

I still se no coating of the laminates PRIOR to installation, which was what my original comment was about, in fact his last pic after one year of use still shows no coating.

I admit I missed his 291, I got a bit hooked up in his condemning of the 3M and its bonding. Personally I would preferr any thing going through my hull to bond at the maximum. I do not concidder through hulls being 'fast moving parts' and if some extra work is needed to get them changed after 20+ (?) years, I do not mind.

But we all have our ways of doing things.

[JeanneP]

I still se no coating of the laminates PRIOR to installation, which was what my original comment was about, in fact his last pic after one year of use still shows no coating.

I assume that what you mean by "laminates" is the Balsa or foam core of a cored hull. I don't think there are any modern GRP boats with a core below the waterline, so I'm not sure that there is any need to paint the hole with resin, particularly since it will be caulked well before the through-hull is installed. A good caulking compound is going to keep the water out. If it doesn't, it's not a good caulking compound.

His picture of the finished through-hull is after one season's use, which is about the same as the sailing season in Norway - May through September. If you mean a coating of the "laminate" to mean the bilge area, why? It's a rare boat that has its bilge gel-coated - certainly our Jeanneau didn't.

[mainesail]

Hi All,

I'm the author of the article in question. On the hulls exterior I did use a epoxy barrier coat to seal the substrates surface before installing the through hulls and I do mention this in the article. Unfortunately these articles are sometimes low on my prority list while I'm physically working and sometimes I foget to bring the camera hence no photos of the exterior being barrier coated.

As for the interior can you please expound on why I would need to "expoxy seal" an area of the bilge that see's no sitting water on the interior of the boat? I think I'm as curious as many are with this comment.

As you can see from the last photo on page two I ground away the gel coated surface, which was purely for show from the factory because I can see where it ends on the other side of the bulkhead, to get good adhesion between the fiberglass backing plates and the hull. The dust was then cleaned up and the surface cleaned with acetone before using a polyester resin filler with fiberglass strands to glass the backing plates to the hull.

Most manufacturers do not coat the entire interiors of hulls with gelcoat or epoxy and only do the insides of cabinets, lockers and the bilge. The bilge, where sitting water would be is obviously the most critical and does need to be coated. My boat is no differerent in this regard and many areas of the bilge that are non visible are not coated with gelcoat. She's a 1979 so if osmotic blistering was going to occur, on the inside of the hull, I probably would have been seen by now.

Perhaps I did not under stand the question but from how I read it I tried to explain it the best I could. The material holding the backing plate in place is fiberglass not "Plastic Padding" I don't know what "plastic padding" is? Before the fiberglass was applied the original gelcoat was removed to create solid adhesion to the actual fiberglass of the hull.

During this process I glassed one of the backing plates in place and then realized it was off by 1/4 of an inch from where I needed it. USER ERROR DUH! I could NOT break this plate free from the hull even using a hammer and crow bar. I know this is not a preffered method for removal but I only tried a hammer and crow bar because this was within less than two hours of glassing it in and I though it might just "pop free" thinking it was not yet fully cured but it did not! I wound up spending the next two hours grinding the backing plate out of the boat only to begin again. If you're worried about strength don't...!

PS. I do plan on re-gelcoating the interior of the locker where the seacock on page two is located. I'll do this strictly for the aesthetic appeal but I did not have time to do it last year before launch..

[MMNETSEA]

Hi Mainesail,

Good to have you on board !!!

A prize to have the originator of an excellent article - well written which made it easily understood - good illustrations and above all, really relevant to our cruising maintenance jobs.

Questions :-

Does Marelon have an advantage over bronze for a through-hull ?

From your 'nom de plume' do you ever get to Brooklin ?

Looking forward to more!

Richard

[mainesail]

Richard,

Marelon most certainly does have benefits! Marelon will never corrode! I wanted to use Marelon on this project but was personally scared away over the broken handles I've had in the past with my own previous use of Marelon. They claim to have made the handles stronger but once you get a bad taste it's tough to go back sometimes. To make matters worse the company did not stand behind the product for me. I was lubing them and maintaining them as directed but they still jerked me around and refuseed to even give me new valves. Here are a coule of pictures of one of my broken valves. Install what ever allows you to sleep at night!

[haffiman37]

JanneP:

I have yet to find an area in my Jeanneau SO37/2002 not top-coated. The inside of the hulls are not gel-coated but top-coated. Basically the same 'stuff' except for the wax solution. Gelcoat which is sprayed/rolled on the moulds does not harden out completely until it is covered by the laminates, where as top-coat haardens out in open air.

Laminates are the build up of epoxy/polyester and fibergalss layers and has nothing to do with balsa cores. In that case You are entering into a sandwitch design.

Top-coating the inside of a hull might be somewhat of a double edged sword as it blocks moisture/water (partly) from getting into the laminates from the inside (condensation mainly), but it even prevents the laminates from ventilating out humidity. This is perhaps the main reason that such an effort is put into preparation of the outside hull by aplying barrier coatings and epoxi. To prevent water from entering into the laminates from the outside. The highest risk of intrution is when cutting through the hull as one at the same time cuts the fibers. Depending on how well air was rolled/'vacumed' out at production, that is a high risk area for water intrution into the laminates. Quite often when removing old through hulls I have seen 'black holes' which is mainly a sign of rotten laminates and in those cases the cut out has not been coated before installation of the through hull. It may not have been a direct leakage through old sealant used, but over 20+ years of time condensation between the through hull fitting and the raw fibers might have caused it.

My recomendation would still be that all areas without top-coat/gel-coat should be coated prior to installation.

Mainsail:

Nice page with good photos. I just made a comment, never intended to start a 'war' .

[Lighthouse]

Welcome aboard "mainesail" - good to have you here.

Your photo essays are fantastic - a great resource for cruisers. Thank you for making the effort to show us all how to do things.

[svReboot]

I note a brief comment about marelon vs marine bronze. I too am having broken handle and sticking marelon valves. Assuming that one side of the brass valve is a marelon or nylon thru hull and the other side a plastic pipe are there any issues with swapping a marelon value to brass in salt water?

[redbopeep]

It would likely be bronze not brass that you'd use. Brass doesn't fare too well in saltwater whereas bronze does. The concerns tend to be between different metals but I wouldn't expect a corrosion concern with a plastic and bronze. Having said that, you might be concerned if the metal part could crack or damage a plastic part just by being used. I wouldn't put a metal seacock on a plastic thru hull for this reason. I note on the picture previously posted here it appears the marelon was stripped out by the metal thread and it appears a poorly engineered design (IMHO).

We've stuck with bronze thru hulls and bronze seacocks. Wherever there's a hull penetration or a "moving part" (like a valve) we've stuck with bronze. The only places we've used marelon are hose-to-hose Y or T connections that don't involve a valve.

Best of luck to you,

Brenda

[osirissailing]

Marelon is far superior to bronze seacocks as they eliminate the electrolysis problems; the lightning strike problems; and the permanently frozen valve problems that bronze seacocks are famous for. . .

The handle of the Marelon seacock is a weak point. But it you know the secret, you can avoid broken handles very easily. Each Marelon seacock is made of three parts; the base, the ball valve, and the top casing. You will notice that there are two large "hex nut" shapes molded into the seacock - one on the base and one on the top body. Any valve will stick if it is not exercised reasonably frequently. When that happens - before you exert excessive pressure on the handle and snap it off - - you put a wrench or spanner on the bottom hex nut portion and another on the upper body hex nut portion and turn counterclockwise a little bit (not too much). This takes the pressure off the internal ball and then the handle will rotate the ball easily enough to "relubricate" the ball. After you have exercised the valve a bit you can tighten the base and upper body back to where they were.

[chopwood]

I really appreciate the essay on repacking the stuffing box. I did mine last weekend in the water. It came with the boat so I had no idea of how old it was and it was getting too warm for my liking.

With the help of the article I was fully prepared, and once I'd cracked it the leak was nowhere as bad as I expected so i could take my time.

Four rings of flax later, and after an hour of run in and adjustment it's cool to touch and no leaks. So Thanks!

[Calliste]

Currently my Bronze Apollo Conbreaco ball valve seacocks are starting to seep sea water from around that 1/8" plug in the side of the seacock body.

These seacocks were installed in San Francisco, circa 1996, and were never bonded.

They have always worked well, no problems turning on or off, and these were the older version that didn't have the valve stem handle problem.

Finally, I removed one of the little plugs, and wire brushed it clean. The threaded portion had turned pink .

Most of us know that the pink color comes from de-zincification, and replacement is needed.

Since I am suspect of any bronze plugs that I might purchase here in Singapore, I have an idea to use the unthreaded shoulder area on long silicon bronze bolts, threading that, grinding the 4 square flats for the wrench, then installing that as a replacement plug.

Would this be a suitable and reliable repair ?

Douglas

[chiroeurope]

Douglas,

If you have the die to cut the bronze and a lubricant so as not to cause the threads to shear off as they are being cut (a problem both brass and bronze share) and can grind the corners down evenly; than yes it would work. Though it might be easier to have them shipped to you from the UK or Canada or Japan. Also if you are going to make the bolt for the hole I would use a matched blind tap (meant to allow bottoming out in a hole) to make sure the inner threads of the plug are in good condition and will mate well with the replacement.

This information does not come from my experience in boat maintenance so please let someone with more knowledge comment. It does come from experience working as an industrial pipefitter and having had to deal with low and high pressure system and making one off parts for machines. As well as good bit of other life and work experience along the way.

Michael

[Calliste]

Thank You for your reply Michael .

My usual problem when cutting threads with a die on a shaft, is that the threads don't cut evenly square to that shaft.

I think it is because I am not able to hold the "Tee" handle square to start the threads, with ?

I did run a 1/8" X 27 tapered pipe tap down into the hole in the side of the seacock, but it didn't bottom out on anything,,,, must be , because it went into the thru hole in the ball , this is the shut off position.

I am wondering if there will be any pink showing on the threaded seacock body, which is not readily vissable ?

Douglas

[chiroeurope]

You are not going to like this answer,

If in doubt check, when you check if in doubt that it will hold and stay functional (not fail) replace it. These are costly words but the other option is much more costly. A failed through hull is not something I even want think about. If the boat is on the hard and you can afford the time for a full check, that would be my best advice. Not what a lot of people want to hear but safest and wisest over the long run.

Michael