How must weight will my mast take with a bosun's chair?

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Pkewish

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My 21 footer has a Z Spars Z710 mast but the seagulls have knocked off the wind speed cups at the top, also the genoa halyard sheave needs attention too. My question is, how much weight will the mast take in a bosun's chair? I'm no lightwaight at 120kg so am planning on volunteering a lighter friend. The only alternative is to have the yard take the mast down and then re-rig at great expense no doubt.
 
I serviced the masthead on my 21 footer using a triple extension ladder - more for convenience than doubts about using a bosun's chair.
 
The Z170 mast is a small section to go up to the top, do you need a yard to take it down? We sail Brightlingsea one Designs that have a Z170 section, we use a A frame attached to each shroud tang and a block and tackle at the spreader height, works very well and no cost! Two old Laser top masts would work (50mm tube).
 
That was my secondary worry but I have a plan for that. My mooring dries out and the keel (1m + wing) sinks into the sandy mud making her very solid, hopefully, solid enough and not putting too much pressure on the keel.
 
Mud sounds good, but you may well find that working above your head awkward and tiring, so I would go for lowering the mast if possible. We used to lower the mast on our Cirrus, 22', without much difficulty and without an A frame, just by extending the forestay and having someone ready to take the weight when it was within reach, though a proper arrangement would be better of course.
 
Or, just pull her over by the nearest jetty. A halyard to the quai will do it very easily. There have been a few stories about 'robust' blokes shinning up small cruiser masts and capsizing them. Have fun :O)
 
Find a friend with a big boat, moor alongside him and go up his mast until level with a line to your mast head - job done.
 
merlin3688 said:
The Z170 mast is a small section to go up to the top, do you need a yard to take it down? We sail Brightlingsea one Designs that have a Z170 section, we use a A frame attached to each shroud tang and a block and tackle at the spreader height, works very well and no cost! Two old Laser top masts would work (50mm tube).
Click to expand...

+1.
We do that on 20ft keelboats with wooden masts, which are quite heavy.
If you can go alongside a quay at low tide, with a few friends, you can easily and safely pull the mast.
Having been a fair way up the mast of a 20ft boat, I am cautious, as if it starts heeling, it can quickly get out of shape.
Another possibility is to go up the mast of a bigger boat and pull the top of your mast over to you. Find a proper cruiser with steps up the mast...
 
No question on my 21fter, the boat is far too unstable with a person any where near the mast top. But then it is a fairly light boat. Further you will find that friction in the halyard system makes a person pretty hard to winch up to the top.
I drop the mast myself each year for winter and used to do it a lot for passing under bridges. I would suggest it would be well worth the effort/cost to modify systems for easy mast lowering. Search mast lowering.
However my little boat was pulled down for a stability test. With helpers this could be the way to go. It takes about 30 to 40kg at the mast top to hold down the mast when horizontal. But a lot more force to get it down past the form stability.
The bow and stern were tied up so that the mast could be pulled down sideways with a halyard. good luck olewill

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I used to lower the mast of our 24-footer each winter for varnishing - an easy 2-person job. Although we did once haul my mum up it when we forgot to reeve the burgee halyard on re-stepping :)

Pete
 
You should be able to lower the mast yourself, we used to do it for a Halcyon 23. As said use an A frame or I used a ladder tied to the mast base to prevent movement, the other end tied to the forestay then gently lowered, we had helpers to prevent sideways movement and 2 people in the cockpit to catch the mast. You must have a tabernacle, would be more difficult if deck stepped.
 
I would be wary of pulling the boat over by the mast. A friend of mine borrowed a squib for an open meeting. He lost the spinnaker halyard, so took the boat next to the quay at Lowestoft. He pulled on the mast & it promptly broke. He was forced to wear the " Dick of the week" jacket at the open meeting & will never live it down
A squib is 20 ft & I have often seen one person drop & raise the mast so 2-3 ought to be able to handle a 21 fter mast by releasing the shrouds & quickly lowering it down the side of the boat then maneuvering it to horizontal. You will get a bit of mud on the heel but easily washed off. Best remove the guard rails first so it does not get caught as you lift it over the side
 
In theory, 120kg is not a problem because the weight is close to the mast and the mast is under compression. However, you will be putting a lot a strain on equipment such as winches/halyard/blocks and the additional load will be transferred on the base of the mast at deck level, depending on the design and condition this may/may not cause distortion. I would use a extended ladder; nice and easy.
 
Is it not a bit risky using a ladder on a boat that size? What happens when you are up top and you shift your weight a bit, the weight of you against the ladder would transfer to a force on the mast causing heeling. Top of a ladder at anything less than vertical is not a good place to be. Just a theory.
 
Daydream believer said:
I would be wary of pulling the boat over by the mast. A friend of mine borrowed a squib for an open meeting. He lost the spinnaker halyard, so took the boat next to the quay at Lowestoft. He pulled on the mast & it promptly broke. He was forced to wear the " Dick of the week" jacket at the open meeting & will never live it down
A squib is 20 ft & I have often seen one person drop & raise the mast so 2-3 ought to be able to handle a 21 fter mast by releasing the shrouds & quickly lowering it down the side of the boat then maneuvering it to horizontal. You will get a bit of mud on the heel but easily washed off. Best remove the guard rails first so it does not get caught as you lift it over the side
Click to expand...

Yikes you won't find me try to drop my mast by handling it like a Scottish caber and dropping it vertically into the mud.
Lower gently on a hinge with tackle and gin poles yes.
I have tried to get a (light weight) person up my 21ft mast. As she got higher the boat started to roll from one side to the other in increasing magnitude rolls until she just wanted to come down again. I mentioned that 40kg would hold my mast horizontal and that was not at the top but at the hounds of fractional rig.
I would say if anyone pulled on a mast and it broke, then be grateful it did not happen at sea as it certainly would have done. My mast in that picture actually takes a lot more load when sailing with 300kg of crew on the windward gunwhale compared to none in the pull down. We have pulled down tested about 6 boats of various types up to 2 tonnes gross and no concerns re rigging. olewill
 
This was me a few years ago, using a Topclimber to get to the masthead. I was probably 13 stone then. Boat was on the hard, on legs, and 22 feet in length. Mast is 29 feet high from its foot.

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View from the masthead, just for info


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And this is how I drop the mast. It takes 3 to lower it, but about 5 to get it back up. I've dropped it several times and it always takes more hands to raise it again.

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This picture was December, now, having fitted new standing rigging it's ready to go up again next week.
 
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