Mast Fitting for Goose Neck

[delevi]

Has anyone had their mast fitting come loose. This is the v-shaped piece holding the goose neck attachment hardware, attached to the mast by rivets. My rivets got quite loose, and the whole deal looks like it can come off any time. I am considering drilling through it and the mast and bolt it down, but I imagine that there was probably a reason that to was riveted. I would hate to lug the boat to the dealer for this, but may have to if bolting it is a bad idea. Any suggestions?

Leon

[DLT]

I bet it was riveted simply because its hard to get to and the forces acting on it would make screws ineffective...

It it were me, I'd probably drill out the old rivets and install new ones.

To do this, you will want to use a drill bit just a bit bigger than the center hole in the rivet. You may have to drill it a second time with a slightly larger bit, if you are too conservative the first time. But, keep in mind, the goal here is to just remove the rivet, not enlarge the hole in the mast... So, drilling twice is better than using too large of a bit the first time.

Now, if the mast is sealed up at the bottom, you'll have the interior portion of the rivets captive within the mast. This shouldn't be a big deal, but just something to keep in mind for later down the road, if you should ever hear something loose inside the mast...

Replace the rivets with ones that fit snug in the holes. You want the body of the rivet to completely fill the hole and not move laterally. Textron Avex blind 'pop' rivets are actually used to build experimental aircraft, so they are probably a good choice for replacements in this application...

[Terry]

The mast is not sealed up at the bottom, I have had my base plate off three times, once to replace the one I twisted (don't ask) again to run antenna wire up the mast and a third time to replace those goofy teflon washers with the ball bearing unit from BWY. If you have a wrench with a long handle extension, a bolt & nut with lock washer might work. I suspect rivets are used to save production time and they work just fine.

[Scott]

It is in fact riveted because you cant get at the backs of bolts. Resist the temptation to drill form the other side as you will weaken the mast at a critical loading point.

Any home improvement store will have SS rivets. (They are stainless) do not use aluminum, it will fail. You can use a normal auto style rivet gun but it requires some serious effort to pop the rivets. If your not up to it take it to an auto shop that has a power riveter or rent one.

[delevi]

Thanks guys. The dealer told me that this is not a warranty issue, since "I sail the boat so hard" and would probably need to replace the rivets once a year. I guess I will go to Home Depot and buy a rivet gun. Anyone know what size is right for the M?

Leon

[They Theirs]

I believe SS will require some insulating bedding under the rivets, as there will be electrolysis with the dissimilar metals. (Aluminum/Stainless) May be better to stick with aluminum rivets in the salt?

Stainless Steel rivets in Aluminum

Galvanic corrosion
Galvanic corrosion occurs when a galvanic cell is formed between two dissimilar metals. The resulting electrochemical potential then leads to formation of an electric current that leads to electrolytic dissolving of the less noble material. This effect can be prevented by electrical insulation of the materials, eg. by using rubber or plastic sleeves or washers, keeping the parts dry so there is no electrolyte to form the cell, or keeping the size of the less-noble material significantly larger than the more noble ones (eg. stainless-steel bolts in an aluminum block won't cause corrosion, but aluminum rivets on stainless steel sheet would rapidly corrode.


When replacing this hardware, use only stainless fasteners (machine screws, tapping screws or rivets; depending on the loads that are to be imparted, aluminum rivets may be used in select applications) whose threads have been coated liberally with bedding compound, as is the case for every fastener used on the spar.

Paul I aboard One Slip
Niagara Falls, NY
05/09 at 08:00AM
I just finished reading an article in the April 2006 issue of Sail magazine. It was an article on Spring commissioning and included info on doing refit work on spars.

With respect to the corrosion issue, the article reinforces some of what I've been thinking right along, but also added a few pieces to the puzzle I did not know.

According to Sail, galvanic corrosion of spar components because of contact with stainless hardware is indeed a significant problem. However the corrosion cannot take place unless there is moisture present. Fastening SS to aluminum and keeping it dry will not result in corrosion. I did not know this.

All water is not the same when it comes to galvanic corrosion and saltwater is markedly worse. Hence the corosion problem is much more prevalent in salt as opposed to fresh water enviornments. I suspected this from what I read in forums like this one, and it explains why my own experience, all on the Great Lakes, show the corrosion problem to be a very minor one.

The article does go on to recommend using Lanocote, Tef-gel, and Duralac for coating fasteners, and Sikaflex 291 or 3M 4200 sealant for larger areas under fittings such as cheek blocks. Do not use silicone that smells of vinegar. It contains an acid that acts as a catalyst to the corrosion process. It is highly recommended to bed all attachments to the mast The use of these sealants is predominately to seal water out, not to isolate the metals. It also tends to stop the threads on screws from siezing.

Recommended fasteners are 1/4"-20 coarse thread screws, 304 grade stainless. According to the article, fine thread fasteners have less thread height and pull out easier.

Aluminum rivits are also recommended for low strength applications. Tap out the mandrels after application if they are made of steel (many are, according to the article). Fill the holes with sealant to prevent water entry.


Lanocote.Prevents Electrolysis CorrosionPrevents Thread Freeze-up


LanoCote works on five basic principals: Displaces water, absorbs corrosion, forms moisture barrier, penetrates and has high lubricity. LanoCote prevents dissimilar metal galvanization. LanoCote is extremely effective in preventing and stopping corrosion on all types of metals under all environental conditions. Formulated to withstand salt water marine conditions, LanoCote is particularly useful in preventing thread seisure due to all types of corrosion on boats and machinery. Applied during assembly, LanoCote will greatly assist in easy dismantling years later. An example would be anchore shackles which are regularly immersed is salt water. LanoCote also combats galvanization where dissimilar metals are fastened together, such as stainless steel fittings on alloy masts

IT PREVENTS THE SEIZING OF METALS & GALVANIC CORROSION BETWEEN DISSIMILAR METALS


This photo shows a section of an aluminium boom that was constructed (re-using old fittings which explains their well-worn look) in September 2003. All stainless steel fittings and fastenings were coated with Tef-Gel before attachment to the aluminium extrusion.


Duralac Corrosion Preventing/Curing


Inhibits electrolytic corrosion of metals
Compound prepared from an elastic varnish medium of low moisture permeability, a corrosion inhibiting materi-
al, Barium Chromate, and inert filler.
Duralac is indispensable for the sealing of joints between dissimilar metals of all types, also valuable for the
protection of metals in contact with wood, synthetic resin compositions, leather, rubber, fabrics etc.

[Chip Hindes]

Any home improvement store will have SS rivets. (They are stainless) do not use aluminum, it will fail. You can use a normal auto style rivet gun but it requires some serious effort to pop the rivets.

Not in my town. Neither Lowes, nor Home Depot, Ace, True Value nor any of the other hardware stores had the SS rivets. I finally ordered them through work from an industrial supply house. Also, don't count on a "normal auto style rivet gun" working. My lightly used $25 made in USA Craftsman gun (not the $10 made in China Harbor Freight version) refused to grip the shanks of the SS rivets.

The dealer told me that this is not a warranty issue, since "I sail the boat so hard" and would probably need to replace the rivets once a year.

That is a crock and I believe unacceptable. There is no caveat in the Mac warranty which says "except for boats sailed hard." This could be used as an excuse for not honoring the warranty for any failure.

I guess I will go to Home Depot and buy a rivet gun.

See above. Home Depot definitely has the rivet gun you need; I saw it there when I replaced my gooseneck fitting. I believe it's $79, hard to justify for six rivets, even if you do have to replace them every year. Cheaper rivets guns were all marked "not recommended for steel or SS rivets" and based on my experience with the Craftman gun, it could just have easily have said "won't work with steel or SS rivets."

I was eventually able to borrow a heavy duty gun. If I were you I'd look at that as my second line of attack, right after making the dealer honor the warranty.

I believe SS will require some insulating bedding under the rivets, as there will be electrolysis with the dissimilar metals. (Aluminum/Stainless) May be better to stick with aluminum rivets in the salt?

Every one of the fastened connectiions on the Mac and nearly every other boat with aluminum spars is SS rivets or screws or bolts in aluminum. The original riveted design from Mac had no bedding. In fact, you need metal to metal contact for the fasteners to hold properly, so bedding them in order to prevent SS to aluminum contact is pretty much an exercise in futility.

You've managed to generate high enough loads to loosen SS rivets; how long do you think aluminum would last?

[normo]

IMHO the recommendation of replacing rivets every year is downright irresponsible. Also, for rivets to work properly the holes must be the proper size. Oversized holes will surely lead to even shorter life.

Couple of suggestions
1. I have an X which uses 3/16 rivets. If your fitting also uses 3/16 rivets I suggest you drill out and go to 1/4 inch rivets as they are much stronger. I have used them on the spinnaker ring and I also plan to use them on the gooseneck fitting for the less bent mast I am transferring hardware to.

I also found that the small hand held rivet guns won't work on the 1/4 inch stainless rivets. A pneumatic rivet gun a friend had didn't work either. I finally purchased a larger rivet gun with long handles from Harbor Frieght for less than $20 and it worked great. It has been used by a couple of others for much larger projects with success. I love Harbor Frieght. Another thought. Our local sailmaker will loan his commercial rivet gun to customers for overnight useage.

2. Much more difficult but worth considering. A few years ago a riveted on spinnaker track pulled completely off of a Catalina mast - all at once. Now that is exciting. I ended up taking a long handle and tied a small wrench to the end. Then taped a nut to the wrench and managed to slide it up the inside of the mast and replace the rivets with screws. Since the gooseneck is much closer to the base of the mast this might work for you.

[Terry]

I ended up taking a long handle and tied a small wrench to the end. Then taped a nut to the wrench and managed to slide it up the inside of the mast and replace the rivets with screws. Since the gooseneck is much closer to the base of the mast this might work for you.

Considering how difficult it sounds to get the tools for SS rivets and how close the gooseneck is to the mast base, a SS nut & bolt sounds a whole lot more simple & easy. The idea above sounds workable and the gooseneck is less than 2 ft up the mast.

[Scott]

May be better to stick with aluminum rivets in the salt?

I repeat and back up Chips assertation, ALUMINUM RIVETS WILL FAIL HERE!!

As for being difficult, Perhaps I have a slightly better than homeowner quality rivet gun but renting a goog on will be far cheaper than buying and easier than landing a nut on a screw 2 feet up a tube.

[delevi]

That is a crock and I believe unacceptable. There is no caveat in the Mac warranty which says "except for boats sailed hard." This could be used as an excuse for not honoring the warranty for any failure.

IMHO the recommendation of replacing rivets every year is downright irresponsible.

Chip & Normo,

I couldn't agree more. This is something my dealer is notorious for. Very difficult to get them to do any warranty work i.e. my daggerboard damage. As for this, I think it would take less time and haslle to fix it myself then hassle with the dealer and lug the boat to him and wait weeks to get it back. The manual for the M spells out the terms of the warranty. At the end, there is an all-inclusive disclaimer that it is at the sole discretion of MacGregor Yachts as to what is or is not considered warranted. The dealer said that to make a warranty claim, they have to take pictures and send them into the factory, get approval, and then can do the work. A crock indeed
Well, I only have a few months left on the warranty. By the way, SS rivets is what the dealer recommended. Absolutely not aluminum. Thanks again for the info everyone.

[Frank C]

Chip,

Home Depot does have SS rivets, on the hardware aisle. I was in there after reading of Leon's problem, and sought them out. They also have standard rivets and aluminum, all in the same section on a carded pegboard display - it's just hard to find them in that vast warehouse. I'm certain they were 3/16" and offered in short, medium, or long. (I doubt they'd have anything like quarter-inch diameter though.)

Since you also found the correct rivet gun, seems that's the best answer for Leon,
since he'd lose a whole day to trailer the boat up to the dealer.


Hey Leon, can I borrow your rivet gun? .... PULEEEEESE?

ETA: Maybe I'm not so sure that I saw 3/16ths SS rivets at HD.
Since Leon found only 1/8 inch, I suppose the ones I saw might have been marked 2/16ths???
Real bummer since the HD version of SS were ~ $2 for a handful, dozen(?) pieces!

[mallardjusted]

Having recently purchased our MacX, this thread has piqued my interest. Is this something that happens to everyones boat, or are there many who have never had this problem ??????

[Chip Hindes]

I've actually replaced the rivets twice, though both times were as a result of the same original indcident, and it was admitedly due to abuse.

I tried to lower the mast without removing the boom. This was the same dumbass incident that broke the cast aluminum cap on the mast end of the boom, covered recently in another thread. It bent the ears on the gooseneck fitting pretty badly as well, which is what eventually led to the second go round.

I replaced the rivets with newly purchased ones, and bent the ears back to their approximate original shape. The weld cracked slightly and I knew it would fail eventually, but it actually lasted another two years before it broke off. The boom was still held on by one ear, but I bit the bullet and replaced the gooseneck fitting anyway. The new fitting from BWY came with the correct SS rivets.

Other than the abuse incident mine has not loosened; though I can't speak for others I'd say it's probably not that common.

Regarding the SS rivets at HD, I'll have to look next time I go. It was two years ago that they didn't have them.

After reading some of these threads I sometimes wonder whether left coast and right coast stores carry different stuff. Everybody keeps insisting that Lowes and Ace hardware carry the Mac-sized hull plugs. Our Lowes has them, but in none of the correct sizes and it's not just that they're out of them; I've asked them to check and they're not listed on the inventory. None of the local Aces carries them at all; they don't even know what I'm talking about.

[Frank C]

HD has begun to carry a small assortment of stainless hardware, like carabiners and anchor shackles. They are vac-packed onto yellow cards as a differentiator, and they carry the word "stainless." The stainless rivets were in bubble pacs, maybe a dozen per. They carry the word, but not sure about the yellow card.

In all 3 of my area stores, the rivets and yellow cards are scattered along the same "pegboard aisle" with rope, nuts, bolts, alum-stock, etc.