I got a new foot !

[Mike in Cape Cod]

Last season (2015 )while winterizing my H23.5 I noticed that two of the four rivets that connect the mast foot to the mast were missing.
I don't know how that happened as I have owned the boat for 13 years and never had any trouble raising or lowering the mast each spring and fall. Always went smoothly.
This spring for safety sake and peace of mind, I drilled out the two remaining rivets and discovered that two of the holes the missing rivets were supposed to occupy in the foot were broken off.
I contacted the SBO website store and was able to have a new foot shipped to me. The new foot arrived and included four stainless rivets and I observed that the new casting needed all four holes to be drilled as well as some material removed with a bench grinder. I learned that my hand held pop rivet tool was not going to get the job done as it would not deform the rivets.
The solution was to buy a heavy duty rivet tool at Harbor Freight which required inserting the correct collet ( it comes with five size rivets and collets) and squeezing the long arms of the tool with all my strength until the rivet popped properly. I now have a sturdy mast foot and do not have to worry about it's integrity.
I know some will say it does not matter if the rivets are loose or missing as there is no force on it when fully raised. Well it sure does matter if that foot separates while raising or lowering the mast.
Note: Hunter used a few different brand masts for the 23.5 and in order to buy the correct cast foot to match your mast , when ordering you must describe the shape of the casting as they sell different shaped castings to match the different masts.
Thank's to the SBO Store people I had a great summer of sailing

 

[flynhi4u]

Good deal. Can't beat Harbor Freight for somethings. Those large stainless rivets take quite a pull to set them.

Sam

 

[Crazy Dave Condon]

Most of the Hunter water ballast were z spar masts/booms now called U S Spars. There was a time when Kenyon Isomat were supplied but those along with Charleston Spar are the same parts that for ease of sake can be purchased from Rigrite from the mfg., Sparcraft. Not sure if the this store can get parts from Sparcraft. If from Dwyer, suggest going thru the site store or SBO store as they know which part.

Long story short Z Spar still exists in France but not in the U S. However, US Spars is synomous with Z Spar as owned by the same two fellows in France. It is easier to go thru this site store or SBO store as they will know which part to get.

 

[alexco38]

Don't forget to use anti-seize compound between SS rivet and aluminium. The SS eats the aluminium due to galvanic interaction. But not too worry, it took 13 years for your's to came to that state.

 

[rgranger]

Small world... I just ordered that same exact part for my H26 this past Monday. Not only had I lost the two ears... mine was torked so it was not sitting flat. Unfortunately.... I know exactly how mine got damaged...

 

[CloudDiver]

DO NOT USE STAINLESS RIVETS IN THIS APPLICATION
Its no wonder the ears are being eaten away.... putting a stainless rivet through an aluminum spar into a cast aluminum mast step... Those rivets serve only 1 function, to keep the spar on the casting when stepping or un-stepping. When the mast and rigging are up they serve no purpose at all, the mast sits on the flange and the 'ears' keep the mast sure footed in the correct position. Look at McMaster Carr and get high strength aluminum 1/4" diameter rivets, the sheer strength x 4 rivets is plenty for this application and you won't end up with the casting eaten away by dissimilar metal corrosion. If it makes you feel better, use 6 to 8 rivets instead of just 4. Aluminum is way easier to drill out and replace too. BTW, Harbor Freight sells a pneumatic rivet gun that works very well and is only $40, comes with multiple tips for various sizes of rivets.

 

[rgranger]

Mine had what looked like brass rivets... but it did not get eaten away... my mast fell half-way through a raising operation.... bad day overall ... with more than just the foot damaged.

 

[flynhi4u]

Mine had what looked like brass rivets... but it did not get eaten away... my mast fell half-way through a raising operation.... bad day overall ... with more than just the foot damaged.

Like my shirt says, "Ship Happens!" Hope everyone was ok.

Sam

 

[CloudDiver]

Mine had what looked like brass rivets... but it did not get eaten away... my mast fell half-way through a raising operation.... bad day overall ... with more than just the foot damaged.

Brass is a soft metal, would not have the sheer strength required.
These aluminum rivets would be my choice, and I would use more than 4 for a good safety margin;
http://www.mcmaster.com/#98778a504/=14hbsbf

 

[rgranger]

Thanks for the link @CloudDiver.

r

 

[Mike in Cape Cod]

DO NOT USE STAINLESS RIVETS IN THIS APPLICATION
Its no wonder the ears are being eaten away.... putting a stainless rivet through an aluminum spar into a cast aluminum mast step... Those rivets serve only 1 function, to keep the spar on the casting when stepping or un-stepping. When the mast and rigging are up they serve no purpose at all, the mast sits on the flange and the 'ears' keep the mast sure footed in the correct position. Look at McMaster Carr and get high strength aluminum 1/4" diameter rivets, the sheer strength x 4 rivets is plenty for this application and you won't end up with the casting eaten away by dissimilar metal corrosion. If it makes you feel better, use 6 to 8 rivets instead of just 4. Aluminum is way easier to drill out and replace too. BTW, Harbor Freight sells a pneumatic rivet gun that works very well and is only $40, comes with multiple tips for various sizes of rivets.

I am confident that the four rivet design that Hunter used are more than sufficient. No need to reinvent the wheel. Incidentally, the cast aluminum foot was not eaten away at all by galvanic corrosion.. The ears broke off at the drilled casting holes. The supplier of the new foot recommended the stainless rivets and actually sent them with the foot stating they are way stronger than any aluminum rivets available. He also added that he has sold a lot of these castings to older Hunter owners as aluminum degrades in salt water. Hey, it lasted 23 years so I will probably not be needing another for some time.

 

[rgranger]

Hey Mike... Mine came yesterday... and it really looks a lot like that spongy "pot metal"... there are even some voids in the metal surface. So I'm thinking I might give mine a quick spray with some of rustoleum's cold galvanizing compound. I've used it on trailers before with great results... my thinking is that any water that makes its way down the inside of the mast will just sit on the surface of the foot.... and work its way into those voids I mentioned. So... anyone see a down side to giving it a quick paint with this galvanizing compound first?

 

[Mike in Cape Cod]

Hey Mike... Mine came yesterday... and it really looks a lot like that spongy "pot metal"... there are even some voids in the metal surface. So I'm thinking I might give mine a quick spray with some of rustoleum's cold galvanizing compound. I've used it on trailers before with great results... my thinking is that any water that makes its way down the inside of the mast will just sit on the surface of the foot.... and work its way into those voids I mentioned. So... anyone see a down side to giving it a quick paint with this galvanizing compound first?

Can not hurt to apply it but I would apply a couple of coats with appropriate dry time in between to provide a thicker coating which is what you want to prevent galvanic action from taking place. You might want to try fitment of the foot inside the mast before you paint it as my new foot required careful drilling of the four holes as well as grinding away some of the aluminum casting to allow it to fit. Good luck ! Mike

 

[Crazy Dave Condon]

As a dealer who often replaced mast foots, I either used the larger aluminum rivets but generally stainless steel rivets contrary to what some will say. The stainless steel rivets were stronger but required the heavier stronger pop rivet gun which now can be purchased much cheaper today than 30 years ago. Most of the failures if not all that I saw were not due to galvanic corrosion as I rarely saw that where the mast foot was attached but due to fatigue. Earlier photos in this post support that. Being on a vertical surface helped tremendously vs. being on a flat surface. Reasons for failure was due to standard aluminum pop rivet fatigue over the years and not enough installed. Another reason was the failure to tighten all the way for one reason or another that pop rivet. Lack of experience is another reason as some put on were sloppy put on.

 

[GGordonWoody]

Thank's to the SBO Store people I had a great summer of sailing

Yaar, they are first rate! I'm amazed they can still get this stuff (although that void and cold flow pattern aren't reassuring).

Looking closely at the pics, I don't see corrosion, and the breaks look smooth, angled, and symmetric. I'm no expert, but this looks like a stress fracture. With the step pin inserted, the mast can rotate back to relieve stress, so never much on the forward rivets. However, rotating the top of the mast forward could impart some serious force to those back rivets, like say when pushing on it to attach the forestay? It's something I did, and I'm definitely going to have a look at that foot, especially with two ships of the same vintage presenting the problem.

BTW, it looks like the new foot has a flange on the aft end, where the old one did not. I know the temptation is to drill there, but I would be careful not to go blasting holes where it feels good. Holes to the sides might offer some forgiveness to the accidental forward lean of the mast during stepping. Again, no expert here, but those guys at Hunter knew a thing or two. I'd keep the holes just where they intended.

Sorry for your problems, but thanks for posting!

 

[GGordonWoody]

Being on a vertical surface helped tremendously vs. being on a flat surface. Reasons for failure was due to standard aluminum pop rivet fatigue over the years and not enough installed.

Hello Sir, can you clarify vertical surface vs. flat surface? Do you mean for applying the rivets, or something else? And did you see more rivet fatigue or foot fatigue?
Thank you!

 

[Crazy Dave Condon]

If you apply the rivets correctly on a vertical surface(tight against the surface) when the mast is standing up, water will run off if the seal of the pop rivet is tight which should be. This is what the old timers who taught me and boy they were right. If you are on flat surface with a rivet, the potential of water pooling may or may not be there and that would be a concern if using dissimilar metals. Hopes this explains this.

 

[CloudDiver]

For those looking for a 'good' rivet gun, believe it or not Harbor Freight has some tools that aren't total garbage. This pic is similar to the unit I have and lists for $69.99, there is another smaller one that is $39.99. I have had both tools and they both work excellent (still have the small one, bigger one was purchased for a job and company property). The big difference is that the bigger unit comes with a tip that accepts 1/4" rivet shanks, where the smaller unit maxes out at 3/16" rivets. Both come with multiple tips for the most common rivet sizes like 1/8" and 3/16", I use the latter most often. They require 90 psi but they do not use much air at all, so a small job site compressor is more than enough. You don't even have to keep the compressor plugged in, the air in a small pancake compressor tank is enough to do several dozen rivets before dropping below required psi. As long as you hold the tool square to the work the rivets will pull home perfectly every time. With a 20% off coupon, either of these guns is absolutely worth having for many jobs.
With the correct high shear strength aluminum rivets I would every confidence this tool would be more than adequate to attach the mast to that foot. I believe 3/16" rivets from the smaller gun would work, but I would use more than 4. BTW, aluminum rivets are SO much easier to drill out than SS ones in the event they need to be replaced.
http://www.harborfreight.com/catalo...ols&RequestData=CA_CategoryExpand&q=rivet+gun

 

[CloudDiver]

For strength visual, here is a pic of how I would place and how many rivets if I were to use the smaller air rivet gun; so max rivet size is 3/16", high strength AL structural rivets are 700lbs Shear and 500 lbs tensile strength. This is obviously not to scale, and a 3/16" hole then domed rivet head will have a more compact appearance than 1/4" rivets.
Keep in mind the 1/4" high Strength AL rivets have a 1300 lb Shear strength rating and 890 lb tensile strength. I'd use more than 4 but not as many as pictured above, LOL... But this will require installing with the bigger gun.

 

[GGordonWoody]

Hopes this explains this

Ha! It does - thank you for taking care of us.

this will require installing with the bigger gun.

...we like big guns! Thanks CloudDiver, you really are amazingly thorough. Does your Cat 22 use the same spar?

As for rivets, the old foot had none in the high forward flange, and didn't even have a flange on the aft end (nearest the step pin). I think no force ever on forward end, not even during stepping, but potentially (obviously?) some on aft end, perhaps during stepping if mast pushed or pulled forward, or perhaps from bashing while under sail? Not sure if any risk from stiffening the spar to foot connection with extra rivets - perhaps none. When raising/lowering mast, keep the ship level across the beam, and level front to back or slightly bow high.