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mike37909
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Mast Step Replacement Material

For thise who have replaced mast step what material did you use?  Any tips?  I read the write up Jason Nimue wrote. He said he used a high grade plywood but didnt say what kind. Regular, pressure treated, or marine. I was thinking of plywood and plan on glassing it in so would regular plywood work?  Seems to me it would.  I also considered a chunk of pressure treated 6x6 like used to build house decks. Seems like a chunk would be quick and easy.  Any other ideas?  

Catalina 36 MK1
1984 Hull #306

 

J.R. Seago
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I used West Systems with cut up fiberglass roving and filler. Was like thin oatmeal. The recipe was given to me from Catalina Yachts, Gerry Douglas. Had to make a mold for 2 sides if I recall. Used very little and I do mean very little catalyst ( can get dangerously hot ). Did it in 3 pours. Capped it off with a piece of 1/4 aluminum plate that I had cut and painted to match the tan floor. Just dropped it on top. 

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Great!  Thanks for this information.  I called technical support at Catalina direct and they said to ask lumber supplier for strongest wood they have.  I like this suggestion completely waterproof and came from the man who knows!

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If/when I do this I'll probably use aluminum, but if in a hurry I'd use ipe (aka. iron wood) with stainless dowels and epoxy.  You can get it at most stores specializing in hardwood or decks (cheaper at deck stores) 
 

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If/when I do this I'll probably use aluminum, but if in a hurry I'd use ipe (aka. iron wood) with stainless dowels and epoxy.  You can get it at most stores specializing in hardwood or decks (cheaper at deck stores) 
 

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I was thinking aluminum also, but the technical help at catalina direct said it would corrode.  Maybe it would last another 36 years :) and then corrode.  He also said no plywood, just a hard rot resistant wood.  I think I will use ipe wood and epoxy and glass.  I plan on closing the fiberglass box so I can pour epoxy in and around the wood.  Probably any hardwood glassed in with epoxy would work, but i understand the loads in compression are high on this mast step.

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I got my piece of ipe wood otherwise known as ironwood.  It was 46 dollars for an 8 foot long by 6 inch wide and 3/4 thick.  Called it a 1x6 they had it up to 20 feet long.  Can you imagine the cost to build a deck out of it.  Supposed to be rot resistant for 20 yrs with no treatment applied.

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I did a 20'x45' deck.   Then when we had the backyard landscaped the architect had me take 7' x 45' off to  "balance" the design. I cried.  

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I cut the inch thick glass out due to the wood being completely rotten and soaked under it. Turns out it was all resin and no glass. 
the timbers are gone so will be replaced with ironwood, glass and epoxy  

So i have to replace the mast step cedar and all the wood under it.  

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Mike,  You sre going to be replacing rotten wood in the bikge with more wood.  Not a great idea.  I would make a box out of Aluminum with an additional center rib.  Weld all the vertical pieces to the bottom piece, then weld the top piece on.  I would probbly use 3/4" inch thick Aluminum plates.  This will out last the Boat.  Another solution would be to make a "pedestal table" with a bottom plate, using either Aluminum or Stainless Steel.  

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This wood is supposed to last 20 years buried with no termites or rot.  The cedar lasted a long time (36 years before mast sunk down), and was not glassed or waterproofed at all.  I agree aluminum would be a good fix but not DIY for me.  Not sure why catalina guy thinks aluminum is not a good idea.  I think as long as it doesn't touch a dissimilar metal it won't corrode too bad.  I have seen pictures of aluminum masts eaten up when put on a steel mast step.  They have to cut a few inches off bottom of mast.  I expect this fix to last around 40 years.  The wood is basically encapsulated in resin and glass.  I also  found a pipe under all the wood that is supposed to drain the mast step area.  It was clogged so i plan on having a dryer bilge.

Mike

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The thing to remember is that wood rots when it has 20 % moisture level.  It does not rot with more or less, but rots as it passes back and forth, rotting when it is at 20 %.  

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Airbus
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So I'm trying to understand the construction of the mast base. From the discussion it sounds like the mast base sits on the mast step which sits on 1" of glass then cedar block then glassed in timber and finally the keel. Is this anywhere close? I was kind of shocked to learn that so much wood was used in this high moisture environment. My mast appears to be down about 1/8". If I take on this project I am leaning towards West System and IPE. Thanks in advance!

Tom
2002 Catalina 36 Mk ll

 

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Airbus,
  In my case and likely all of the older catalina 36 the mast step is like this.  
The casting is screwed into the cedar block through the fiberglass hull liner.  The cedar on my boat was sitting on an inch thick pour of resin.  There is kind of a fiberglass box that holds this resin and the cedar, with the resin being the bottom of the box.  Unfortunately on my boat and probably all of them, their are wood timbers going crosswise (athwartship?) under this resin.  I was able to dig under the resin and pull out rotten wood.  I cut the resin out with a grinder while a helper held vacuum for the dust.  I removed all rotten wood I could find.  The floor isnt square or level so I started glassing in pieces of ironwood.
So from top to bottom:
casting 
hull liner (gel coated floor of cabin)
cedar block
fiberglass and or resin pour
wood timbers
 

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Mike, Thanks for that detailed description. My mast base casting sits on what appears to be the hull liner but is actually seperate from the hull liner. It is a machined rectangular piece that is just larger than the casting and is caulked around the edges to appear as part of the liner. This caulking had lost adhesion which I am wondering is due to compression. I removed the caulk and and probed around the edges with an awl expecting soft wood but it is hard as a rock and did not appear to be wood unless maybe it was impregnated with resin. I recaulked and will look for any additional compression this season. Thanks again for your imput.

Tom
2002 Catalina 36

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Are you the original owner?  Sounds like it was already fixed but who knows?  Mine didn't have a plate that was caulked in. I do not think that is original but it might be.  My boat didn't really match the pictures or drawings I have seen of other catalina 36.  My guess is that on top of your wood is a layer of resin and maybe glass.  Might be thin or thick.  If your step is collapsing the wood on the bottom is probably rotted.  I had some material that looked like wood but was resin, and got under it from the side and found major rot.  You could drill a hole and see what comes out, or get under it somehow.  I let mine go until the shrouds suddenly got very loose one windy day.  They were always tight before this.  Not the best idea....I split a crane 3 ways so was only 200 dollars to pull mast.  

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I have only had the boat 2 years so Its possible work was done prior. I suppose if there is wood decay it will show up in the next few months. That project does not sound very pleasant. Thanks again for your input

Tom
2002 Catalina 36
Old Saybrook, Ct

dhickmanii
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I had mine replaced last year and got rid of all the wood.  The step was replaced with a replaced with a fiberglass beam.  It was then glassed in to make it sturdy.  
 

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Wow you removed a lot of the liner.  Looks like a great job that will outlast all of us.  Mine is similar but I didn't cut the liner, except the part the casting sits on, and the casting  came out when I pulled the mast. I was able to get to other parts through the removable floorboard and the door.
Thanks for sharing pics.

dhickmanii
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They put it all back.  Looks as good as new. 

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