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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Lowering mast - tall rig

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dmpilc
Master Marine Consultant

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USA
4593 Posts

Initially Posted - 05/27/2008 : 22:10:39

I put our new A-frame to the test today. Made it out of 2x4's similar to some other designs seen on this forum, with an eyebolt at each rounded off end, connected to the forward lower chainplates via a D-shackle. all of this from our friendly HD. The mast came down okay in spite of one mishap which could have been real trouble, but wasn't. After watching the you-tube video, I was going to try this by myself, but the admiral wisely said NO to that - "you can pretend you're doing this alone, she said, but I'm going to be there just in case you need me." As it turns out, there was another boat owner on the dock who offered to help, and I had him on a safety line attached to the forestay as a back-up if needed. He claims he never had to tension the line.
Here's what did happen: A 6"x3/8" bolt connects the two 2x4's at the top of the A-frame and holds two caribiners. The jib halyard is connected to the upper caribiner and a 3/8" line is connected to a block with becket at the bow and up to the lower caribiner for a 3to 1 purchase, then back to one of the jib winches. I pulled on the back stay, and as I was lowering the mast, we heard a loud pop noise, which the guy on deck with the safety thought was the mast shifting in the mast step. We continued and the mast came on down without incident. What we found out later was that one of the eye bolts at the botton of the A-frame, and attached to the forward lower chainplate via the D-shackle, had opened up completely, therefore separating from the deck entirely. This left only the upper shroud and aft lower holding the mast on that side.
I'll also mention that I had attached the forward lower shrouds to a pair of screw-in eye bolts on the top edge of the A-frame about 5 inches up the wood. Both of those eyebolts opened up just slightly. I'm going to have to use the 5" tangs next time and attach the forward lowers to them directly to the chainplates.I'm going to also have to replace the primary eyebolts with welded ones, and maybe the other ones as well.
All of this was in preparation of pulling the boat out tomorrow to fix the keel trunk leak. While it is out, I'm going to do the all-rope halyard conversion and install the new mast step plate from CD.
I'll try to posp pictures later.

DavidP
1975 C-22 SK #5459 "Shadowfax" Fleet 52
PO of 1984 C-25 SK/TR #4142 "Recess"
Percy Priest Yacht Club, Hamilton Creek Marina, Nashville, TN

Edited by - dmpilc on 05/27/2008 22:16:43

sweetcraft
Admiral

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USA
816 Posts

Response Posted - 05/28/2008 : 00:16:03

Do you think the edge of the end of the 2 X 4 might have touched the deck and caused the eye to open? A dry run without the mast might show the point of resistance. Welding the eye closed might cause something else to give so double check. I don't use a rigid A frame for my tall rig but a rope bridle and the gin pole method. Keep refining your method so it becomes easier and you sail more. Pictures will help so the others that use the A frame can help.

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Davy J
Master Marine Consultant

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USA
1511 Posts

Response Posted - 05/28/2008 : 08:58:47

Posting pictures will help. But from what I can see from your description, here is what I think. The geometry between the forward lowers/chainplate (and in your case, the a-frame) changes drastically as the mast goes from up/down or down/up position. I had to experiment with this on my rig to find the right amount of tension in the "middle" so that it would not be to tight at that critical time. In addition, my forward lowers are connected directly to the chainplate. In your case, it sounds like the forward lowers are too tight. And since you mounted them 5" up from the chainplate this is also pulling backward on the a-frame itself. This would cause backward tension at the chainplate connection. If you only have to raise the mast once or twice, and you have help, you probably do not need to worry about connecting the forward lowers at all. Just have somebody keep the mast from swaying side to side. This is all that the forward lower connection does.

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dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 05/28/2008 : 22:46:43

We'll check this out when we get theboat back from the shop. Unfortunately, we forgot to take pictures. The eye bolts were 1/4". I've replaced them with 3/8" eye bolts for the next application. Thing is, I thought that with the D-shackles in place attached to the chain plates, the eye bolts would simply travel up the curved shackle body and not bind at all. I'll have to pay close attention to that next time.
We hauled the boat today and delivered it to the shop, so I guess I'll be sailing the C-22 more for the next few weeks.

Edit: Took another look, Eye bolts actually were less than 1/4", more like 1/8 - 3/16".

Edited by - dmpilc on 06/01/2008 14:57:20

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The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.