G10 Material for Mast Step

Blitz

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Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
Has anyone used G10 to create their own mast step for a keel stepped mast to avoid corrosion and deterioration of the factory cast aluminum step?

Would the compression of the mast on a flat sheet of G10 with a raised center wear G10 through vibration? From what I've read is that G10 should be up to the task of compression, and the raised center of the step could be bolted/epoxied in.

I know the obvious question would to possibly ask a rigger.

I've seen some posts on other site where someone will also shorten their mast and raise the step to get it out of the bilge water and any standing water that may come down the mast. Any suggestions would be welcomed.

Advantages are obvious to lesson corrosion of the step and end of the mast. Many older mast steps are becoming no longer available and might also be the only solution.
 
May 22, 2020
9
Pearson 303 Casco Bay
Although I did not considering using G10 to directly support the mast, I have used G10 to create a riser for a mast step that I had fabricated to replace a corroded one (the prior owner had placed a "dam" in the bilge to keep the step dry and stop the corrosion).

I never remember to take a good set of before and after pictures, but the attached should give you an idea.
 

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Jan 27, 2008
3,045
ODay 35 Beaufort, NC
G10 in terms of resistance to wear from the vibration will be better than aluminum. G10 is really hard stuff. I made some backing blocks for thru hull fittings and had to shape them to fit the hull. It is really tough material to sand and shape. You could probably bond two pieces together then mill them on a milling machine to create the raised center section. As far as shortening the mast it is a better idea to just get longer turnbuckles or toggles to allow for the higher mast height. They also make longer swage fittings so you could potentially cut your swage fittings off your rigging and replace them.
 
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Oct 9, 2008
1,739
Bristol 29.9 Dana Point
The yard did this exact thing on my boat 6 years ago. It’s been fine since; shroud tension same, no signs of oddities.
 

Blitz

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Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
illusion - nice metal work, is that aluminum again?

jibes - if I was to cut off the mast, it was for two purposes: cut off a little bit that was corroded and to raise the mast a bit out of any bilge water. my mast isn't corroded any worse than ten years ago. I was thinking based on recommendations to sand the mast and prime with a two part primer and repaint. I had a strong recommendation to use a barrier coat for underwater metals, topped with a bilge paint. Ten years ago I painted the mast and new aluminum step with an aluminum spray primer and Interlux Bilge coat. The step still corroded pretty badly.

The goal is to stop corrosion of the step and mast as much as possible.
 
Jan 27, 2008
3,045
ODay 35 Beaufort, NC
Got it. If you cut an inch off the mast and make the step an inch taller no rigging change correct? One problem with aluminum is once you cut it any protection from the original anodizing is lost as bare metal is exposed to mother nature. As you know aluminum is a highly reactive metal and is used as an anode for galvanic corrosion protection. At the very least the bare aluminum should be protected by using what is called "alodine" or "conversion coat" which creates some protection for the metal but is less effective than anodizing. This stuff is what you need Amazon.com: Henkel - Alodine 1201 Light Metals Conversion Coating, Quart: Automotive.
 
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Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
I used G10 to replace the plywood under the mast on my deck stepped C30. Worked great and I now have no concern about rotting the core.
 
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Blitz

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Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
jibes:. sounds like you might have experience. what would you think about treating with alodine, applying the Total Protect barrier, then bilge paint?
 
Jan 27, 2008
3,045
ODay 35 Beaufort, NC
Alodine will provide good adhesion for paint. You might want to try zinc chromate primer after the alodine. That is typically used where dissimilar metals are in contact. You could also coat the aluminum with epoxy as once cured it gets pretty hard and adheres really well. Anything you use to increase the dimensions will have to be allowed for in the fit to the mast step (obviously). I coated my keel with West system epoxy after sanding to bare lead as the paint kept peeling. Lead is very reactive and oxidizes fast so I had to work quickly. Two coats of epoxy and I haven't had any paint adhesion issues on the keel in at least 20 years. After the epoxy I did hot coat InterProtect barrier coat and then hot coated the bottom paint. Hot coating means you apply it before the epoxy or barrier coat is fully cured so it bonds chemically instead of mechanically.
 

Blitz

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Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
I wanted to update my previous posts to show the result of my spring mast step project. I chose NOT to shorten the mast to get it out of the wet bilge area but to refinish the mast (Kenyon) end and recreate the aluminum mast step with G10.


Ten years ago when I had the mast out I took many pictures of the mast base, and in comparison the corrosion of the mast was the same as it was now. Back then I only used Zinc Chromate primer and two coats Interlux Bilgekote. This time after a thorough prep of the aluminum mast, I ended up priming the base of the mast with Zinc Chromate primer, three coats of barrier coat (Total Boat: Total Protect), and three coats of Interlux Bilgekote. The guys over at Total Boat seemed to think this method should be good.

The existing aluminum mast step couldn't be reused since it was corroded badly & soft but not so much that I couldn't get some basic dimensions off of it for reference. The step was recreated with a block of 1-1/2" thick G10 (McMaster Carr) and a 5/16" G10 sheet to be used as the bottom plate. It took some time using a router (went through a few bits) and some careful use of a bench top belt/disk sander to recreate the step.

While the mast was down, I also changed all the wire standing rigging as well as the turnbuckles and any pins.

Overall, the project seemed to work out great, and with the rig tuned she has been sailing great.
IMG_20210418_150423490_HDR.jpg
IMG_20210430_151109197.jpg
 
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Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
Did you enlarge the rain-drain hole in the back part (or front) of the spar bottom?
And add a silver dollar to the inside, on a dot of sealant to keep it from moving and plugging the drain hole.
Nice workmanship, BTW!
:)
 

Blitz

.
Jul 10, 2007
672
Seidelmann 34 Atlantic Highlands, NJ
Did you enlarge the rain-drain hole in the back part (or front) of the spar bottom?
And add a silver dollar to the inside, on a dot of sealant to keep it from moving and plugging the drain hole.
Nice workmanship, BTW!
:)
Yes, should have mentioned that I enlarged the holes slightly and added one above. Silt, dirt or whatever will clog those holes. When I took the mast out last fall I realized that there was probably a two foot colum of rain water in the mast since the rain drain holes (which are in the back channel of my Kenton mast) were clogged.
 
Jun 30, 2022
3
pearson pearson323 rock hall maryland
The yard did this exact thing on my boat 6 years ago. It’s been fine since; shroud tension same, no signs of oddities.
Hi!
Where did your rigger place the G10 plate ? Ours put one in at our request, but it’s under the mast step not between the mast step and the mast. (boat is being Rerigged, mast currently unstepped.)
We thought he’d place it between mast step and mast, not under.
The yard did this exact thing on my boat 6 years ago. It’s been fine since; shroud tension same, no signs of oddities.
hi!
Did your rigger put the G10 between the mast and mast plate or between The mast plate and the fiberglass ? Our boat is bring rerigged, and he put it under the mast step, between it and fiberglass. This didn’t make sense to me. Is it correct? You can see it in this photo under the mast step.
 

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Nov 6, 2020
96
Mariner 36 California
Hi!
Where did your rigger place the G10 plate ? Ours put one in at our request, but it’s under the mast step not between the mast step and the mast. (boat is being Rerigged, mast currently unstepped.)
We thought he’d place it between mast step and mast, not under.

hi!
Did your rigger put the G10 between the mast and mast plate or between The mast plate and the fiberglass ? Our boat is bring rerigged, and he put it under the mast step, between it and fiberglass. This didn’t make sense to me. Is it correct? You can see it in this photo under the mast step.
That seems like a great place to put it. G-10 can handle high compression loads so it makes sense to me they would put it under the mast step where there is more surface area compressing the g-10 directly downward. It also gets the base of the step slightly up out of standing water although maybe not enough to be a huge help on corrosion.
 
Jun 30, 2022
3
pearson pearson323 rock hall maryland
That seems like a great place to put it. G-10 can handle high compression loads so it makes sense to me they would put it under the mast step where there is more surface area compressing the g-10 directly downward. It also gets the base of the step slightly up out of standing water although maybe not enough to be a huge help on corrosion.
thanks for your response!
But I thought the point was to prevent corrosion between the stainless steel mast step and the aluminum mast. Will it still do any good if its not between them but instead between the stainless steel mast step and the fiberglass ? It seems the function then is just to get it out of water. We have a Pearson 323.
 
Nov 6, 2020
96
Mariner 36 California
thanks for your response!
But I thought the point was to prevent corrosion between the stainless steel mast step and the aluminum mast. Will it still do any good if its not between them but instead between the stainless steel mast step and the fiberglass ? It seems the function then is just to get it out of water. We have a Pearson 323.
I think to prevent corrosion the entire step would have to be made from G-10? Your mast base would make contact on the flat base of the step as well as the internal supports that are welded to the base. Im not sure a single flat piece of G-10 would have helped your situation much because those tabs would still make contact on the inside of the mast. . Also, if that G-10 is thick enough, maybe there was some concern that if it was put onto the top that those tabs would not protrude far enough into the mast itself to keep it securely in place? Just guessing? Maybe there is enough of a gap between the walls of those tabs and the inside of the mast itself to put a liberal coating of epoxy as a barrier?
 
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Jun 30, 2022
3
pearson pearson323 rock hall maryland
Thank you very much
I think to prevent corrosion the entire step would have to be made from G-10? Your mast base would make contact on the flat base of the step as well as the internal supports that are welded to the base. Im not sure a single flat piece of G-10 would have helped your situation much because those tabs would still make contact on the inside of the mast. . Also, if that G-10 is thick enough, maybe there was some concern that if it was put onto the top that those tabs would not protrude far enough into the mast itself to keep it securely in place? Just guessing? Maybe there is enough of a gap between the walls of those tabs and the inside of the mast itself to put a liberal coating of epoxy as a barrier?
thank you very much for your response! I appreciate it.