Requesting Advice: Corrosion on Lower Mast & Mast Step

[toms-gonesailin]

Hi guys!

Just discovered a bit of corrosion on my lower mast and mast step and would love feedback from you kind folks on the best approach here. My questions are:

1. What's the best solution/treatment now so it doesn't get worse?
2. How bad is it On a scale of 1 - 10? ("10" being OMG go deal with that right now before your mast falls off and "1" being meh it's fine.
3. What's the recommended approach for the most comprehensive fix?
4. Does anyone have riggers in the New York state area that they trust and recommend?

I've included a link to a video that should give you a better sense of extent of the corrosion. Feel free to mute the sound if your not into the music...

https://www.youtube.com/watch?v=QgyLWOIukTk

Thanks for your time and help. Much appreciated.

[tkeithlu]

Even with the video, I can't really come to a conclusion about structural integrity, although it looks scary. You may be in the market for a good surveyor.

This may fit in the "low probability of failure but a disaster if it does" category. I would be inclined to explore replacement.

[Breaking Waves]

Well, you need to pull the mast out to do anything - once you do that you will be able to inspect it better. You definitely need to clean it up and stop the corrosion, can't know if/how much you need more than that without looking inside.

The mast may or may not come off the mast step - it might be corrosion welded on. If it will not come off, then you cut the corroded section off, and splice on a new butt section. You need a rigger with decent aluminum fabricating experience (not just a 'tune-up' rigger).

Or it may come off easily, and look ok inside, in which case you can clean up and recoat and be good with the mast.

I guess the mast step will need to be replaced in any case.

Where exactly is the boat - there are a lot of riggers and fabricators in 'new york state'.

[a64pilot]

Mine wasn’t that bad but at almost 30 yrs old at the time, it had significant corrosion.
I had the mast pulled and the step removed, we had though maybe it would be best to have a machine shop make a new one, but on inspection it was OK, so I had it anodized and then Epoxy primed and re-installed.
On installation I soaked everything with Corrosion-X
My mast was also fine, but I was going to have a couple off inches cut off of it if it were necessary as the rigging was being replaced anyway.

With a crane pulling on it, the mast will likely come loose, but be prepared for it to jump a little when it does.

[Island Time O25]

I had a similar issue about 6-7 years ago. I sanded the mast bottom section a bit, sprayed several coats of primer and epoxy paint and that was that. You might want to throw a few old zincs into your bilge, it will really help with galvanic corrosion.

Also I know that my mast step needs to be replaced, I just haven't decided to either do it in aluminum or in a G-10 fabrication. I'm tilting toward G-10 for vairety of reasons, main of which are my SS keel bolts.

[guyrj33]

Build a new mast step a few inches higher.
Cut a few inches off the bottom of the mast.

[stormalong]

Looks like you may have water coming down your mast and no drain for it to clear.

I would pull the mast and the step, sandblast the bottom foot inside and out. Have a pro check it out and then decide on a plan.

The first thing is drainage, Then if it is still strong, prime and paint both the step and the mast. Anodizing is a preferable alternative for the mast step.

[toms-gonesailin]

Thanks so much for all the great replies. Much appreciated. I’m a total boat noob so I’m going to ask a lot of basic questions. Hopefully someone else rereading is wondering the same thing.

My takeaway is:

step 1 - arrange to have the mast pulled so I can inspect and reassess extent of corrosion.

Q1: Does anyone have a good step by step or check list of things to consider when removing the mast? This would be my first time and I don’t entirely trust the yard…

If corrosion is NOT bad anodize the mast and epoxy prime

Q2: What does it mean to Anodize?

If the corrosion IS bad I’m cutting “a couple” of inches off the base of the mast and building the mast step up

Questions re cutting the mast

Q3: Do I cut all of the parts corrosion off?
Q4: Should I try and cut it my self or pay a rigger to do it?

Questions re “building the mast step up”

Q5: Do I take the existing mast step to a machine shop and tell them this but “a couple inches taller”?
Q6: Or and is it better to build up the support under the step and keep the size and shape of the existing step.

I’m also happy to be pointed to other threads where people have delt with this same issue. No need to reinvent the wheel. Just trying to get as much info as I can since this is all pretty new to me and I REALLY don’t want to mess it up. Also if it's that obvious feel free to tell me to go "google it" Also if there are references to books that cover it I'm happy to be referred to those as well.

Originally Posted by Breaking Waves

Where exactly is the boat - there are a lot of riggers and fabricators in 'new york state'.

The boats in Brooklyn currently on the hard for the winter.

Thank you, thank you, thank you

[Breaking Waves]

Originally Posted by toms-gonesailin

Thanks so much for all the great replies. Much appreciated. I’m a total boat noob so I’m going to ask a lot of basic questions. Hopefully someone else rereading is wondering the same thing.

My takeaway is:

step 1 - arrange to have the mast pulled so I can inspect and reassess extent of corrosion.

Yea. Yards and contractors can sometimes get “complicated”, so worth chatting with yard and riggers before giving anyone go ahead.

Q1: Does anyone have a good step by step or check list of things to consider when removing the mast? This would be my first time and I don’t entirely trust the yard…

It’s not hard, and pretty standard thing to do. In normal process you just need to make sure the jib furling foil is treated gently and doesn’t not get kinked. in your case there might be a bit of jerking with crane or hammering inside to get that mast step off. But nothing a working yard has not seen before.

If corrosion is NOT bad anodize the mast and epoxy prime

Q2: What does it mean to Anodize?

You buff all the corrosion back to shiny aluminum. You can’t actually anodize it, but look up Alodine Aluminum treatment to see the sort of metal prep to do. (Edit looks like that brand name has been changed since the last time I used it to BONDERITE M-CR 1201). There are other decent similar products which prep the aluminum surface.

If the corrosion IS bad I’m cutting “a couple” of inches off the base of the mast and building the mast step up

You can either build up the step or sleeve the butt of the mast. There are pros and cons. Building up the step is easier requires less skill.

Questions re cutting the mast

Q3: Do I cut all of the parts corrosion off?

Judgement call. If it’s only 4” or so, then sure. If it’s more than that then you need to thing about potential side loading on the stack under the step. You can certainly leave a minor cosmetic corrosion spot or two, so long as you get them to clean metal and treat.
Q4: Should I try and cut it my self or pay a rigger to do it?

How handy are you. It’s really just cutting aluminum tube. But you need a clean and square job. Sometimes mast butts are slightly slanted to create designed mast rake.
Questions re “building the mast step up”

Q5: Do I take the existing mast step to a machine shop and tell them this but “a couple inches taller”?
Q6: Or and is it better to build up the support under the step and keep the size and shape of the existing step.

Either can be done. Depends a bit on how high you need to stack and what material you use. You can use something called g10 (quite strong fiberglass sheet) to build the stack up. You can also use it to make a new step. It will then never again corrode. Or you can remake step in aluminum.

I’m also happy to be pointed to other threads where people have delt with this same issue. No need to reinvent the wheel. Just trying to get as much info as I can since this is all pretty new to me and I REALLY don’t want to mess it up. Also if it's that obvious feel free to tell me to go "google it" Also if there are references to books that cover it I'm happy to be referred to those as well.



The boats in Brooklyn currently on the hard for the winter.

I’d give a call to

Performance Yacht Management
pyminc@yahoo.com
City Island, NY

If they can’t help you, will probably give you some guidance on who can. I have not dealt with them in quite a while and companies can change, but they were honest and competent back then.

Thank you, thank you, thank you

..........

[stormalong]

Q1: Start with removing anything mounted on the mast that will be an issue: radar dome, wind instruments, etc., disconnect all wiring - looks pretty obvious from your picture but try not to cut any wires - trace back to connection points and disconnect there., remove all sails and furling line., Remove boom, loosen rigging. If you have a strut below deck remove it, Remove boot/mast collar, turn it over to the rigger/yard to complete the job.

Q2: Anodizing is an electo-chemical process to build up a protective layer on aluminum. Can be done on the mast step but not the mast - too big.

Q3,Q4: Sounds like you are not familiar with tools - leave it to a professional.

Q5,Q6: Have a machine shop make a whole new mast step. Be sure to have a drainage path to the bilge.

[P3sailor]

That is some nasty corrosion. I'd venture to say the step is beyond repair so I would try to purchase a replacement from the manufacturer or have one manufactured using aluminum of the same type and thickness. I also would recommend having the mast NDT'd (Non-Destructive Testing) to determine the extent of the corrosion that you cannot see. Eddy-Current and Utra-sonic testing are two methods I'm familiar with. You can clean up much of the corrosion by using walnut shells, glass beads, wire brush, etc. I wouldn't sand-blast only because it can remove more metal than desired if you're not careful. You'll need to etch and alodine the bare surfaces prior to painting, the nice thing about the etch (acid) is any existing corrosion will appear black when the etch is applied. You could most likely be able to purchase the etch and alodine from any aircraft maintenance facility and they also may have NDT personnel on hand they'd be more than happy to "farm" out to assist you. If the facility has a paint shop they should have everything you need to complete the repair properly. Good Luck with your project.

[stewy]

In your case the corrosion is heavy so a simpler solution won't likely apply but for those with less severe corrosion on aluminum there is a product called "Corrosion Block" that has been used by the US Navy. It is a coating that is applied to the metal as a protectant. I can't substantiate its effectiveness.

[Franziska]

Not sure how much space you have at the mast collar.

Here would be a low budget solution for someone comfortable with lamination.

I once fixed (a deck stepped) mast foot with corrosion by thoroughly cleaning it than glass it over high enough with two layers of glass & epoxy followed by wrapping it thoroughly with several layers of carbon tape and epoxy.
All was vacuum baged during curing.

Worked fine for many years.

It's important to find and stop the cause of corrosion first though.
The glass layer is important to separate carbon and aluminum.
The layup was tapered at the upper end as to not create a hard spot. Where the layup ended we had a 3cm by 0.5cm UV resistant strip of Sika for safety against water getting in.

Good luck!

[jmschmidt]

OMG go deal with that right now!!!!!!! Way, way too late to pull the mast and cut 1/4 to 1/2 inch off the bottom, remove the step and replace or reweld to the original speck.

Good luck.

[JC Reefer]

Originally Posted by guyrj33

Build a new mast step a few inches higher.

Cut a few inches off the bottom of the mast.

This is what I have done in the past. Works great. I see not reason why you couldn’t fab one out of g-10.

The old step will def be stuck on there. Spray her down with vinegar and let it soak for a day. Should help resolve some salt at least.

I personally don’t think it’s that bad but it is tough to tell from the video.