I recently read a post on one of the Facebook Com-pac groups about someone who sailed the Texas 200 with his Sun Cat. On the second day out his mast pushed through the rotted plywood mast step and the mast sank 3 inches. He put some wood under it for a quick fix to finish the race, but was looking for advise on a more permanent repair.
I looked at the mast step on my Sun Cat today and noticed that the area under the mast is depressed some. There is a plywood cover screwed down a several inches to port of the mast and it was soaking wet and delaminated. This is making me question the integrity of the plywood beneath the mast. I couldn't find that Facebook post again, but I remember him saying that Hutchens had come up with a fix for this problem. I searched this website for "mast step" in the Sun Cat and Horizon Cat sections, but only came up with one post that didn't have a solution.
Does anyone know where there is information about fixing this problem?
I read that also and immediately thought of Chris and our keys trip this past January.
The fix was a metal plate over the plywood framing.
Here's a couple of links. The first is general discussion of mast stepping safety, but included in the thread is the report of near dismasting by Bremer Speck on his 2004 HC. Gerry went to the boat and saw that the mast step had rotted and repaired it with 1/2" SS.
https://cpyoa.com/forum/index.php?topic=3653.0
This later thread of a similar condition, with good photos, shows Com-Pac had gone to 3/8" aluminum for the repair. Much easier to work with common workshop tools, and less potential for galvanic corrosion.
https://cpyoa.com/forum/index.php?topic=9583.msg72203#msg72203
Thanks Bruce. The information you provided is very helpful. I've been following your posts over the years and they have always been knowledgeable and helpful. It looks like the "factory" repair using 3/8 inch aluminum would be the best way to go. However, now that Hutchens is closed, I would have to get a custom made piece to fit the way theirs did. Also, I'll have to remove the bulkhead to get the plate in there. It's ironic, I live half an hour's drive from Com-Pac's former factory. I knew Gerry since the 1980's. Great guy. Wish I had discovered this problem before they closed.
The boat is now in a slip, but I'll be bringing it home soon and I'll try to determine how extensive the plywood rot is. If it's not too bad, I'm thinking of getting the widest piece of 3/8 aluminum that I can fit through the bulkhead door and affixing it to the structure under the mast step to spread the load. I'm assuming that the mast step is screwed into the "floor" and then slid into the mast stub with some adhesive sealant. Won't be much fun separating those two. Any ideas?
Robert,
I don't think it will be too hard to do. I don't have a Sun Cat handy to check out the access to the mast step, but even if the size of the metal plate you can squeeze in is limited by access you should be able to get in something large enough so it bears on sound framing. This, of course, is critical to determine, and many tend to optimistically think that the margins just beyond the clearly rotted wood are structurally sound. They rarely are.
If access is that limited, you might consider using thick bars, or maybe better because they're stiffer, angles of aluminum that bridge the damaged area from sound attachments, that a smaller plate could be fastened onto. Another layer of thickness, but you're adding less than an inch, not that critical. You could even trim the mast stub so there was no net change.
McMaster Carr is a great source for small quantities of industrial materials, including aluminum plate, bars, or angles. Reasonably priced, but I often can do better on eBay for more common items like aluminum plate. I'd design using McMaster Carr, see what the price was and decide if I wanted to check other sources.
Here's a couple of links to get you started:
Aluminum sheet, 6061, 3/8" thick, dimensions from 13" to 29" in length and width, for $0.70 per sq. in.
https://www.mcmaster.com/products/metals/aluminum-3~/shape~sheet/made-to-order-multipurpose-6061-aluminum-sheets~~/
Aluminum angle, 6061, 1 1/2" x 1 1/2", wall thickness 3/8", up to 8'.
https://www.mcmaster.com/products/metals/aluminum-3~/shape~90-angle/multipurpose-6061-aluminum-90-angles~~/wall-thickness~3-8/outside-corner-shape~square/
I just checked Amazon, and you can get a 24" x24" piece of 3/8" 6061 aluminum for about $200. Aluminum can be cut with hand-held power tools, a jigsaw or a circular saw would be fine for the plate.
I posted working diagrams that Dwyer Mast provided for the Sun Cats spars. The mast step is part #D2140 for the DH375 mast. It's just a simple cast end cap, in fact they used the same part at the top of the mast as you can see. I would assume it's screwed to the plywood, with sealant, and the mast fits over the top and is bolted from the sides. That's what it looks like in the second link in my previous post. Especially if the plywood is rotten, it shouldn't be too hard to pop it off. We can probably find that part if necessary, even since Dwyer has closed.
https://cpyoa.com/forum/index.php?topic=11288.msg85117#msg85117
Bruce: Thanks again. I agree with you that if the plywood under the step is rotten then the mast stub will probably just lift out. McMaster-Carr looks like a good source for aluminum. I plan to trailer the boat home from the slip where she is now berthed in the next couple of weeks. In Florida it is too damn hot to do that kind of work now. I plan to seal around the mast then cover the boat until the Fall when the weather starts to cool off. Then I can dig into it and determine the extent of the rot. I'll keep you posted. Thanks for your help. Enjoy the 4th of July holiday. I'm sure it's not too hot to sail up where you are.
Agreed, cooler weather will be much nicer.
Another thing that hasn't been mentioned is freeing the mast stub so the mast step can be worked on. It may be, once the mast is free of the step, it will slide up in the mast partners/collar enough to give you room. You may, of course, find sealant here too.
McMaster Carr's website is great, and they are a pleasure to work with, but at $0.70 a sq. in. a 24" x 24" sheet of 3/8" aluminum will cost a bit over $400. Watch the shipping prices on longer items as well, like the angle. If you need two pieces of 24" for example, ordering two pieces of 24" may be cheaper than one 48" piece, with the shipping.
check area welding shops