Perahps I've been away from sailing for too long with our long wet winters here and I'm just looking for something to worry about. Hopefully you can help. I will be installing a wind meter at the top of the mast on our 1999 H310 in a few weeks. I will be using a bosuns chair and with my luck, I expect to be up and down more times than a toilet seat at a mixed party. If you consider my weight at 180 lbs. and my weight pulls down on one side of the main halyard block while someone pulls down on the other side with an equal and opposite force of 180 lbs., the mast is now loaded down with an additional 360 lbs. Has anyone ever experienced or heard of this causing any problems with the mast assembly when making numerous trips up and down the mast ? Thanks for your input.
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Wim van den Toorn
Dutch invention?
The UK magazine "Practical Boat Owner" published a mast climbing device some months ago which limits the weight on the mast. The claim it is a Dutch invention. Send me your fax number and you'll get a copy. Wim
The UK magazine "Practical Boat Owner" published a mast climbing device some months ago which limits the weight on the mast. The claim it is a Dutch invention. Send me your fax number and you'll get a copy. Wim
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Eric Lorgus
I may not have the physics right, but
Ralph, I had a rigger do some work on my mast last month. He used a bosun's chair with a block & tackle setup that reduced the force required to raise the chair (employing the principle that each block reduces the total effort). He let me borrow it so that I could take a look at the top of my mast. It was relatively easy to pull myself up using his rig. So, I'm guessing that with a similar rig the total force being applied at the masthead would be much less than body weight times two that you surmised. There's also a device called the "Topclimber", made by ATN in Ft. Lauderdale, 954-523-3034. There was a story in 12/2000 Soundings about it. It's a bosun's chair that enables crew to ascend the mast unassisted by pushing their legs down on foot straps, which pulls climbers up. It can put the climber above the masthead, which most chairs don't do. BTW, whatever you use, don't forget a safety harness to break your fall should your climbing gear fail. When I'm being hoisted in a conventional bosun's chair, I tie a line around my chest & under my arms, with the other end tied around the mast. As I ascend, I slide the mast connection up as I go. Eric Lorgus s/v Impulse 83H54
Ralph, I had a rigger do some work on my mast last month. He used a bosun's chair with a block & tackle setup that reduced the force required to raise the chair (employing the principle that each block reduces the total effort). He let me borrow it so that I could take a look at the top of my mast. It was relatively easy to pull myself up using his rig. So, I'm guessing that with a similar rig the total force being applied at the masthead would be much less than body weight times two that you surmised. There's also a device called the "Topclimber", made by ATN in Ft. Lauderdale, 954-523-3034. There was a story in 12/2000 Soundings about it. It's a bosun's chair that enables crew to ascend the mast unassisted by pushing their legs down on foot straps, which pulls climbers up. It can put the climber above the masthead, which most chairs don't do. BTW, whatever you use, don't forget a safety harness to break your fall should your climbing gear fail. When I'm being hoisted in a conventional bosun's chair, I tie a line around my chest & under my arms, with the other end tied around the mast. As I ascend, I slide the mast connection up as I go. Eric Lorgus s/v Impulse 83H54
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R.W.Landau
Ralph
If you are going to have some help getting you up the mast, Make it easy on everyone. Rig your bosins chair to the main halyard. Don't just use the connector, the splice is the weakest point, tie a bowline. Add a safety line, the jib halyard, also tied with a bowline.The main halyard can be taken back to the starboard winch. The safety line can be handed on the mast winch. Once they pull your a.... up the mast, secure both lines. A third line, the spinaker halyard can be used to send tools, parts,and beer up to you while you are working. It will cut mast time down and also the dangerous part, the trip up and down. You can use a small duffle bag for the tool transfer. good luck r.w.landau
If you are going to have some help getting you up the mast, Make it easy on everyone. Rig your bosins chair to the main halyard. Don't just use the connector, the splice is the weakest point, tie a bowline. Add a safety line, the jib halyard, also tied with a bowline.The main halyard can be taken back to the starboard winch. The safety line can be handed on the mast winch. Once they pull your a.... up the mast, secure both lines. A third line, the spinaker halyard can be used to send tools, parts,and beer up to you while you are working. It will cut mast time down and also the dangerous part, the trip up and down. You can use a small duffle bag for the tool transfer. good luck r.w.landau
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Dr. R. A. Brown
Physics 101
The question you raise is a favorite of the Professional Engineering Exam. If you tie the tail of the halyard off to the mast or another part of the boat, your analysis is correct; twice your weight is the compression load on the sheaves at the masthead because you are using a two to one purchase. However, if you hoist yourself by the tail and tie the tail off to your bosun's chair, then each piece of the halyard holds only one half of your weight, and the load on the sheaves is only your weight, not twice. Neat, hunh?
The question you raise is a favorite of the Professional Engineering Exam. If you tie the tail of the halyard off to the mast or another part of the boat, your analysis is correct; twice your weight is the compression load on the sheaves at the masthead because you are using a two to one purchase. However, if you hoist yourself by the tail and tie the tail off to your bosun's chair, then each piece of the halyard holds only one half of your weight, and the load on the sheaves is only your weight, not twice. Neat, hunh?
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Jim Ewing
What I do
I have two Main halyards, I use the primary as the hoist and the secondary as the safety line. Both are tied (as recommended in the earlier post) to the bosun's chair and the safety also goes around me (in case the chair fails). You do NOT want to make many trips up and down the mast because 1) if your friend is doing the cranking you will be left up the mast after the second trip or 2) if your wife's doing the cranking you will be left up the mast AND divorced. I use a canvas bucket on a hauling line to move tools, parts, etc up and down. The hauling line is my dive float line so it has it's own handle and way to secure everything. I tie all power tools by the cord (I don't have any battery tools) to the chair or spreader. If I'm feeling unlucky I spread the cockpit cushions on deck under me in case I drop a wrench (bounce...splash is better than crack...splash) When you're working on the masthead it helps to have something to stand on so you can actually get to the top. There are steps made for this or you can use a board on a line. One last nightmare scenario, never tie yourself to the masthead. If there's a medical emergency when you're up there you'll stay up there... We also use a hands-free radio set so we're not heard all over the marina yelling for the same parts or tools (or drink). If you set it up right and have everything prepped you can spend all the time you need at the top and get it done in one trip. Jim "Prospect"
I have two Main halyards, I use the primary as the hoist and the secondary as the safety line. Both are tied (as recommended in the earlier post) to the bosun's chair and the safety also goes around me (in case the chair fails). You do NOT want to make many trips up and down the mast because 1) if your friend is doing the cranking you will be left up the mast after the second trip or 2) if your wife's doing the cranking you will be left up the mast AND divorced. I use a canvas bucket on a hauling line to move tools, parts, etc up and down. The hauling line is my dive float line so it has it's own handle and way to secure everything. I tie all power tools by the cord (I don't have any battery tools) to the chair or spreader. If I'm feeling unlucky I spread the cockpit cushions on deck under me in case I drop a wrench (bounce...splash is better than crack...splash) When you're working on the masthead it helps to have something to stand on so you can actually get to the top. There are steps made for this or you can use a board on a line. One last nightmare scenario, never tie yourself to the masthead. If there's a medical emergency when you're up there you'll stay up there... We also use a hands-free radio set so we're not heard all over the marina yelling for the same parts or tools (or drink). If you set it up right and have everything prepped you can spend all the time you need at the top and get it done in one trip. Jim "Prospect"
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Ralph Johnstone
Wim van den Toorn ................
Wim, Would be most obliged if you could arrange for a copy. Sounds interesting. My fax number is (604) 987-7465. Thanks, Island Hunter
Wim, Would be most obliged if you could arrange for a copy. Sounds interesting. My fax number is (604) 987-7465. Thanks, Island Hunter
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