mast head

Re: mast head

Postby gamayun » Thu Dec 20, 2018 8:22 pm

Perhaps I should mention the new jib sheave box that we also built. This required an expert in CF repair. What an ordeal, but the old sheave box was barely hanging on inside the mast (bad design to begin with) and the sheaves were a constant source of friction because of the way they were right on top of each other. Now I have a separate box for the jib halyard and a little offset from that is the spin halyard. I'll get some mast pictures of everything put together one of these days....

Jib box sheave_after.jpg
Jib box sheave_after.jpg (17.15 KiB) Viewed 1287 times


CF layup at the jib sheave box.jpg
CF layup at the jib sheave box.jpg (16.03 KiB) Viewed 1287 times
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Re: mast head

Postby Castaway » Fri Dec 21, 2018 11:01 am

Mike Cunningham writes:
"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. "

I'm not sure how frightened I should be. The F33/35 cat ketch has two masts with external halyards hung fore and aft from each. I regularly use them to ascend the masts, aided by my wife on the power winch, and there has been no sign of impending dissolution of the cranes, the U bolts, or the blocks; the latter are replaced from time to time. I suspect my mass of around 70 kg is much less than the maximum load when the halyards are holding the sails up, though my skin is more precious than mere Dacron. I think you are being overcautious, Mike, but better that than chancing a fall.

I use a flat tape safety line wrapped twice around the mast and attached to a safety harness as a fall arrester, just sliding it up and down as I go. I've not tried it in earnest yet, but it does hold me in place if I don't shake it loose as I descend. No fancy knots needed, and equipment any sailor should have to hand.

BTW, the last time I used it the aluminium plate was thiry-one years old, and appeared perfect.
Oh, and Gamayun, that new crane and the sheave boxes look awesome!


Regards,

Gerald
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Re: mast head

Postby ketch22 » Fri Dec 21, 2018 12:20 pm

Looks beautiful Gamyun. Great job. Should be good for another 30 years.

tm
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Re: mast head

Postby lewharve » Fri Dec 21, 2018 6:28 pm

other than the Klemheist knot is there any place to secure a line on the mast head. like over the shive and out the front
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Re: mast head

Postby lewharve » Mon Dec 24, 2018 3:39 pm

all this great but I am down here and my broken shive is up there
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Re: mast head

Postby gamayun » Mon Dec 24, 2018 4:16 pm

Lew, if you don't have a functioning halyard, I really only see two choices: drop the mast or get hoisted up there on a crane. If you feel confident, then it might be possible to shimmy up with a klemheist/prusik type of arrangement around the mast itself. I've seen it done on trees where you can get some purchase, but those CF masts are slick and it's a long way to the top. I certainly wouldn't ever consider it because I'm a chicken when it comes to heights. I climb in a harness with two halyards, one of which functions solely as a backup to the first. Everyone is different as to which risks they're willing to take. As to getting a line around the sheave, that's not possible unless you have a line already run through the sheave and the sheave is functioning such that the line can run smoothly in the groove and not jump off. The sheave itself is inside the housing of the masthead crane with the halyards running inside the mast and out the back (for the main halyard). I wish you all the best in getting this fixed!
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Re: mast head

Postby Castaway » Mon Dec 24, 2018 5:14 pm

Lewharve,

If you only have one halyard at the masthead, I would go for the crane option. Even if you have to hire the crane, it ought to be cheaper than pulling the mast, then stepping it again.

I have seen a professional rigger use the mast of another (larger) boat to get up to masthead height, then pull the masts together to do the job. With an unstayed mast on at least one boat, there is little risk of entanglement or damage.

Either possibility is better than using your own halyard, since it gets your head and arms level with the top, so you can see what you are doing, and work more comfortably.

Good luck,

Gerald
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s/y 'Castaway', (UK F35 cat ketch, centreboard, 1987)
Lerwick Boating Club
Shetland Isles, Scotland
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Re: mast head

Postby Camino » Mon Dec 24, 2018 5:26 pm

Gamayun- that masthead work of yours is awesome! On halyards, this is my first boat with a single main halyard and that kills me. When I bought the boat I did manage to jam my main halyard on my first sail with the power winch and me not paying attention. The jam occurred just at the 7/8th jib halyard location so when I sailed back to dock I could use the jib halyard to haul me up to free my main jam. Any higher would have been a big problem. On internal halyards, I have no hesitation to climb in harness using the single halyard - as if the sheeve does break, the halyard is not in a free fall position to kill me but will stop an inch or two below the sheeve break. I can climb down the mast (rather slide down). Now it’s another beast altogether having a halyard run outside and attached with a u-bolt to the crane, everything just hanging free. That would require a safety line to me but clearly the climbing would be dependent on the condition/maintenance of all components - so if in good order, I’d climb that as well.

On a 2009 Hawaii crossing double handed, we did break a main halyard and spin halyard through chaff. We had extra halyards!
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Re: mast head

Postby Goose13 » Fri Jan 18, 2019 4:55 pm

As Rock climber with 20+ years of experience, I use the prusik knot, with two pieces of 20’, one inch webbing to go up my mast. Last fall the halyard block broke off my mast head on my F33 CK, so I hand no choice but to climb up the mast with no halyard. Wrap the two pieces of webbing around the mast, connect the top one to your harness and then connect the lower one to your harness as well and add two stirrups to the bottom piece of webbing as well. Your feet go in the stirrups and now u inch up your mast like a catapillar. It takes about 10 min to get to the top and about 10 down. The only way this method can fail is if your mast breaks and we all know how strong these masts are. As a side note the further u go up the skinner the mast and your going to have more slack in your prusik lines as you go up. I have to go up my mizzen soon so I’ll try and make a u-tube video and post is on line for u.
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Re: mast head

Postby Camino » Sat Jan 19, 2019 9:09 pm

Doug- I’m interested! So the Prusik knot will hold around a mast using webbing.... a YouTube posting would be terrific!
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