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Old 02-02-2016, 18:48   #1
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Installing folding steps and galvanic corrosion

On my Helia, it's exceptionally difficult to attach the head of the mainsail to the main halyard block shackle. This is due to the characteristics of it being a square mainsail and the height at which it needs to be attached. There's a contraption (i.e., a jack line system) that can be rigged to overcome this, but I don't want to junk up my mast with it. For now, I've decided that I'll attach folding steps on both sides of the mast because being at least a foot higher would definitely help.

Of course, the mast is aluminum and my steps are type 316 stainless steel (Sea Dog Folding Step-Cast SDG-3280201). I only know enough to know that mixing metals is not recommended in certain cases, especially considering galvanic corrosion. That said, I'm considering stainless steel bolts to attach them. Mistake? Advice? Is it really a concern? Am I over analyzing this? TIA!
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Old 02-02-2016, 20:00   #2
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Re: Installing folding steps and galvanic corrosion

I had aluminum folding steps all the way to the top of the mast, but the screws were stainless steel. I have not had a problem with them since 1996, but I will find out how I did when I remove the hardware from the mast when I paint it.
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Old 02-02-2016, 22:07   #3
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Re: Installing folding steps and galvanic corrosion

In terms of using stainless fasteners in aluminum; standard practice is to coat them with one of the various compounds which will electrically isolate one from the other.
Tef-Gel is a common one, & for bolts that I want to isolate, but ensure that they stay put, Blue Loc-Tite is in my "bag of tricks".
And "Blue" is underlined, so that you don't use Red, or something similar, which is almost sure to guarantee destroying something, when you go to try & remove the fasteners.

There are others as well; Duralac (sp?), & some folks will use Never-Seize: Although the molybedenum in it strikes me as making it's use questionable for long term app's involving Aluminum. Given "moly's" place on the galvanic scale.
And in a pinch, some guys will even use fingernail polish (BTDT). Or for other app's, epoxy of one sort or another is called for.

Though to be certain of your work, & the efficacy of your isolating agent, you can just disassemble things with some regularity... while being gentle on the threads, that is.

Also, if you're Really concerned about galvanic corrosion, you can us aluminum fasteners. So that the mast wall, at least, will be "safe". Though you'll still need to paint the undersides of the aluminum bolt heads, where they meet the mast steps.

Plus: As a tip for the maximum efficacy of your steps. Mount enough of them, closely enough together; so that it's easy for your shortest crew member to climb up them, while wearing several layers of heavy clothing. This, when the boat's bouncing around a lot.

That, & locate the top most pair (or pairs; for folks of greatly differing heights) so that the headboard & shackle are positioned at chest level for the shortest crew member. As at that height, it's easiest to simultaneously hold onto the mast, & work on things/the head of the sail.

PS: If in doubt regarding any of this, talk to your local rigger. And or, hire them for an hour or three of their expertise & instruction.
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Old 02-02-2016, 23:03   #4
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Re: Installing folding steps and galvanic corrosion

I don't have "granny bars" but I'm wondering if they might be a good place to stand if designed with that in mind.

My boat came with mast steps to the top but they're not as easy to use as I'd hoped.
I'm over 6 feet but the steps are nearly 2 feet apart so my considerable weight is always on one foot - very tiring.

Seems to me that standing on something a little way away from the mast would let you lean into the mast with arms securely around it and both hands free to work.

Haven't tried it though, so I could be talking out of my fundament again.
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Old 03-02-2016, 08:47   #5
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Re: Installing folding steps and galvanic corrosion

We used monel rivets ....... and also use two parallel steps at the mast head to avoid standing on one foot and the strain that creates.



Quote:
Originally Posted by SailMonAmi View Post
On my Helia, it's exceptionally difficult to attach the head of the mainsail to the main halyard block shackle. This is due to the characteristics of it being a square mainsail and the height at which it needs to be attached. There's a contraption (i.e., a jack line system) that can be rigged to overcome this, but I don't want to junk up my mast with it. For now, I've decided that I'll attach folding steps on both sides of the mast because being at least a foot higher would definitely help.

Of course, the mast is aluminum and my steps are type 316 stainless steel (Sea Dog Folding Step-Cast SDG-3280201). I only know enough to know that mixing metals is not recommended in certain cases, especially considering galvanic corrosion. That said, I'm considering stainless steel bolts to attach them. Mistake? Advice? Is it really a concern? Am I over analyzing this? TIA!
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Old 03-02-2016, 16:05   #6
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Installing folding steps and galvanic corrosion

SailMonAmi,
The Helia 44 mast is anodized, so it has a thin surface skin to prevent corrosion.
I would still use a coating of BoatLife – Lifeseal (clear) to bond it on and seal it.

Stainless steel bolts will be fine, but make sure to use a fine thread tap like a 12-24 or a 12-28 to give you more thread surface area as the mast is less than 1/8inch thick. A course thread would only give you a few threads of holding and may strip out.

A #12-24 Tap will use a #17 (.173) tap drill
A #12-28 Tap will use a #15 (.180) tap drill

As said earlier. You will want to use Tef-Gel or Loctite Blue 242 on the threads.

Some cruisers like to use the composite steps with all aluminum rivets to eliminate any possibility of galvanic corrosion.

I have used composite steps in the past and they work well and are much easier and faster to install by using all aluminum rivet’s.
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Old 03-02-2016, 16:37   #7
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Re: Installing folding steps and galvanic corrosion

It should be fine, but you will get some corrosion. Often the lower 5-6 ft of mast gets quite corroded anyway. Use Lanolin on all threads or Tef-gel or etc. for sure.
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Old 03-02-2016, 18:44   #8
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Re: Installing folding steps and galvanic corrosion

Quote:
Stainless steel bolts will be fine, but make sure to use a fine thread tap like a 12-24 or a 12-28 to give you more thread surface area as the mast is less than 1/8inch thick. A course thread would only give you a few threads of holding and may strip out.
There was a recent and lengthy discussion of this here on CF. The overwhelming consensus from the engineers on board was that for thin sections one should always use a coarse thread. Have you a reference that refutes this?

Jim
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Old 04-02-2016, 00:24   #9
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Re: Installing folding steps and galvanic corrosion

Quote:
As a tip for the maximum efficacy of your steps. Mount enough of them, closely enough together; so that it's easy for your shortest crew member to climb up them, while wearing several layers of heavy clothing. This, when the boat's bouncing around a lot.
Boy, you got that right! AS a shortie, it really helps. Some guys install mast steps when they're in their late 30's, and never mind they're 6'4" tall, and now comes along shorty crew. Man, it's impossible: Their steps are too far for us to fill!

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Old 04-02-2016, 17:59   #10
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Re: Installing folding steps and galvanic corrosion

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Originally Posted by Jim Cate View Post
There was a recent and lengthy discussion of this here on CF. The overwhelming consensus from the engineers on board was that for thin sections one should always use a coarse thread. Have you a reference that refutes this?
Jim
Maybe this will help
Best way to fasten something to a Sailboat Mast
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Old 04-02-2016, 20:14   #11
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Re: Installing folding steps and galvanic corrosion

Quite a lot to consider, especially when I had thought that it was going to be a simple matter of slapping them on without regard to engineering or corrosion. Thanks to all who contributed to this thread!
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