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mast head

Posted: Wed Dec 19, 2018 5:16 pm
by lewharve
Like I said the main sheet shive is broken. pulling the mast costs a grand here and I really don't have the money.
I have a mast climber so I can get up there but how do I secure myself up there so I can take the pressure off the main halyard so I can replace the main halyard
Thanks

Re: mast head

Posted: Wed Dec 19, 2018 7:44 pm
by Ereiss
My guess is you need to climb twice. Once to install a line to use for the second climb. Second climb replace sheeve.

Haven't thought where you will secure this temporary line but there should be a spot to run the line through.


Just my winter thoughts.

Re: mast head

Posted: Thu Dec 20, 2018 12:38 pm
by gamayun
This is why I now have blocks attached to my mast head to be able to run another halyard (or 2) as backups. The problem I see is that you don't have any backup and your primary has failed. I don't see how you can climb this safely. I bit the bullet, took the mast down and did a complete over haul of the masthead crane, replaced with new sheaves and added u bolts for the blocks. I completely get it about the money. Boats will do that. Can you check with another yard? A thousand bucks to pull the mast seems a bit much to me. I don't recall how much it was in the San Francisco Bay area but it I think it was a few hundred. The big expense was leaving it in the yard for a while while I worked with a friend to build a new masthead and sheaves. Sorry I can't be more helpful. Good luck on getting this fixed!

Re: mast head

Posted: Thu Dec 20, 2018 1:50 pm
by JohnReinagel
Lewharve, I have used Klemheist knots to climb the mast via halyard. It's actually an old knot used for climbing rope but I also use it around the mast so in case a halyard breaks this knot will tighten around the mast and stop me from falling much more than a foot or two. I connect the knot to my bosuns chair and slide it up the mast as I assend. Once at the masthead you can most likely add the second line to the masthead that suits you needs and rely on the Klemheist knot around the mast while you change from halyard to whatever line you just added. Good luck and be safe.

Re: mast head

Posted: Thu Dec 20, 2018 1:56 pm
by RadioZephyr
gamayun wrote:This is why I now have blocks attached to my mast head to be able to run another halyard (or 2) as backups. The problem I see is that you don't have any backup and your primary has failed. I don't see how you can climb this safely. I bit the bullet, took the mast down and did a complete over haul of the masthead crane, replaced with new sheaves and added u bolts for the blocks.
Wow, it sounds like a major overhaul to your stock masthead! I'd be interested to see pictures if you have them.

Where did you find room to attach u-bolts? Is your masthead the "old style" or the "new style"? The older mastheads have a large plate with plenty of overhang for adding hardware, but the new version is much slimmer, and has almost no space for that. It does, however, have two small sheaves at the front and back, that allow a messenger line to be run for an emergency halyard (the thin yellow line in the second pic). The idea is that if you lose your halyard, you can run a new line to the masthead, and use that line to hoist up a block to serve as an emergency halyard (or to hoist someone up).
Old style masthead
Old style masthead
IMG_0548 (2).jpg (222.69 KiB) Viewed 7038 times
New style masthead
New style masthead
IMG_1835.jpg (128.99 KiB) Viewed 7038 times

Re: mast head

Posted: Thu Dec 20, 2018 2:26 pm
by mike cunningham
I would never depend upon the overhang of the original mast top plate on my 30 to support me or a halyard used for hoisting a sail. IMO it is suitable for a flag halyard only. The original halyard sheaves (main, jib, kite) keep the load mostly in column with the mast.

I have used my flag halyard to retrieve the main halyard when I lost control of the main halyard at sea and had the damn thing run all the way up the mast so it is a very useful halyard but not one designed to carry much load.

I have used a kleimheist in 1.5 inch webbing as a backup safety like another poster mentioned. You could use this technique to get weight off the sheave while you replace it but God forbid you run into problems and can not get the job done for whatever reason. Now you are stuck at the masthead. Perhaps the thing to do would be get to the masthead, do a kleimheist and transfer a block (and yourself) to the kleimheist so you can use it to get down if necessary. This would require some rehearsal on or near the ground.

I had a forestay break unexpectedly a number of years ago and one of the yard guys went up on a crane to fix it. The mast did not have to come out, I paid for crane time and the guy. Cost around $200. You might consider this possibility, some yards have a mobile crane. Maybe they would let you go up yourself so all you pay for is crane time.

Re: mast head

Posted: Thu Dec 20, 2018 2:36 pm
by mike cunningham
RadioZephyr wrote:Wow, it sounds like a major overhaul to your stock masthead! I'd be interested to see pictures if you have them.

Where did you find room to attach u-bolts? Is your masthead the "old style" or the "new style"? The older mastheads have a large plate with plenty of overhang for adding hardware, but the new version is much slimmer, and has almost no space for that. It does, however, have two small sheaves at the front and back, that allow a messenger line to be run for an emergency halyard (the thin yellow line in the second pic). The idea is that if you lose your halyard, you can run a new line to the masthead, and use that line to hoist up a block to serve as an emergency halyard (or to hoist someone up).
IMG_0548 (2).jpg
IMG_1835.jpg
That is really interesting. Last time I had my mast down I took a look at the plate (old style on F30) and its attachment to the mast. I was thinking of removing it for inspection but gave up after fussing with it for awhile. It looked like major surgery to get it off. How did you do it?

I did not feel a 30 year old aluminum plate was a good candidate for additional loading such as would be necessary for a spare halyard, especially one used for climbing. Am I being too conservative? I really like the idea of Having a robust set up with a leader as you have described. That way you could run up a heavy halyard if it became necessary but would not have to deal with that halyard as a permanent feature.

Re: mast head

Posted: Thu Dec 20, 2018 2:45 pm
by RadioZephyr
I took out the two screws through the sides and then whaled on it from below with a dead blow mallet till it came out. It's just held in there with some epoxy. The problem with the old style masthead is that the weld holding the bottom part onto the plate tends to fail after about 30 or so years. Also, it can't take a larger sheave. When I put in the new masthead, I upgraded mine to a Harken 754 "high load" sheave. The original could only fit the Harken 500 sheave (same as are in the mainsheet blocks).

Re: mast head

Posted: Thu Dec 20, 2018 8:12 pm
by gamayun
I've been meaning to post some pics of the mast crane birthing process that I went through in March 2016 so thanks for the prompt to get this done. I worked with a friend in his machine shop, which did require skills and tools that I don't possess, especially welding! Basically, we took the old masthead crane base and built a larger piece to bolt over it (see first pic). This had "bump outs" for the u-bolts. It was also extended to accommodate a new tri-color. I replaced the VHF antenna and upgraded the VHF wire to minimize frequency loss. I also finally got around to installing he new B&G wind speed sensor that I'd bought nearly 3 years earlier. We built new aluminum sheaves and then everything was hard anodized, which I will post in a subsequent message because 3 is the limit here. I also wrapped all the wires in insulating foam to keep them from banging so that means if I ever need to replace something, everything has to come down again. Hoping that does not become a problem. I have heard others using large Teflon ties or some PVC pipe to run the wires and keep them contained.
Birth of the beast_3-4-16.jpg
Birth of the beast_3-4-16.jpg (24.55 KiB) Viewed 7010 times
Dry fitting of mast crane_3-6-15.jpg
Dry fitting of mast crane_3-6-15.jpg (20.22 KiB) Viewed 7010 times
Sheaves step1.jpg
Sheaves step1.jpg (33.18 KiB) Viewed 7010 times

Re: mast head

Posted: Thu Dec 20, 2018 8:14 pm
by gamayun
Here's the final look before it all went back up in the mast, but before the sheaves and blocks were installed. You can also see the base of the tri-color, but not the light itself. I need to get a view from the top one of these days. I still look up and admire it often :D
Pipe insulation around mast wires at crane_5-16-16.jpg
Pipe insulation around mast wires at crane_5-16-16.jpg (65.04 KiB) Viewed 7010 times