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-   -   Preventing sway when unstepping mast (http://www.sailnet.com/forums/gear-maintenance/78754-preventing-sway-when-unstepping-mast.html)

cdhickey 09-14-2011 01:02 PM

Preventing sway when unstepping mast
 
Unfortunately, my sailing season is soon coming to an end and I need to deal with putting the old girl away for the winter. I'm going to try unstepping the mast on my 24' for the first time and have searched and read quite a bit on the topic. My plan is to use a ginpole with a winch (like discussed here ). My biggest question is how to best avoid the mast swaying from side to side (or more likely, right into a neighboring boat) when being lowered. I will have at least one helper with me who may be able to guide the mast as it comes down. I would also leave my shrouds attached- the chainplates are in line with the mast step but about a foot lower and I'm not sure how much help they will be once the mast starts to drop.

I have seen a number of solutions for unstepping a mast using bridles to reduce sway such as the one discussed in Good Old Boat here and those referenced in the ginpole article. These seemed to be aimed at those doing the deed solo- are the necessary for unstepping with a helper, or would they be overkill if I'm working with a helper?

tommays 09-14-2011 01:09 PM

On the J24 are pole is 20' and stands up on deck 10" forward of the mast and held stable by three shrouds

We use a 4:1 block and tackle and raise a bridle up the mast to a point we KNOW is balanced and secure it

The J24 is keel stepped and requires about 36" of lift before you can start to lower and tilt it to a horizontal position

SHNOOL 09-14-2011 04:34 PM

I was going to build an A-Frame before haul out (this weekend ugh)... I still am, and I will report back. Everyone I have seen build an A-frame, secured it to the mast with a fixed length and used the mainsheet to pull the A-Frame up (or let it down in our case)..

I propose to do the opposite, fix the line to the forward cleats, and use my mainsheet to rotate the mast downward. I will have about 7 foot of height to the mast, and the 3to1 of the mainsheet should provide ample strength to slow the decent. My wife and I raised the mast together, so this will give her twice the strength to better help me. I'll be catching! hehehe. Oppurtunity for her to off me now!

Here is a drawing I obtained of a gin pole arrangement that was sent to me as an alternative (again hand built):
http://www.shnool.com/images/_Capri1989/MRSys0001.jpg

OtterGreen 09-14-2011 04:40 PM

on my santana 23, we have one person on the forestay lower it slowly, one person on the deck to walk her down and ease her into the crutch on the stern. its easier with three people but i just restepped her post irene a few weeks ago with one other person. make sure to minimize crosswind either bow or stern to the wind. being steady, smooth, and everyone knowing their role and what to do to avoid an accident is crucial. make sure they know everystep thats going to happen. you dont want someone saying wait? what do i do now?! the process on my boat takes about 5 mins to drop when done properly.

AdamLein 09-15-2011 01:38 PM

I built an A-frame a couple of years ago for my C-27 to do some work on the mast. Didn't have any problems with the mast moving sideways as long as somebody was minding the base of the mast.

The pieces of the A-frame are stored below, out of sight until the next unstepping :)

okawbow 09-15-2011 02:39 PM

I use a piece of 1/4" chain shackled to 2 of the stantion bases on each side of the mast. The length of the chain is adjusted so that a halyard attaches at a point even with, and the same height as the mast hinge point. That keeps the mast from falling to the side.

Izzy1414 09-15-2011 03:40 PM

Quote:

Originally Posted by okawbow (Post 775229)
I use a piece of 1/4" chain shackled to 2 of the stantion bases on each side of the mast. The length of the chain is adjusted so that a halyard attaches at a point even with, and the same height as the mast hinge point. That keeps the mast from falling to the side.

If I'm reading this correctly, my system is similar and works well. I have three legged guys on each side of the mast. One leg attaches to a stanchion base forward of the mast and one to a stanchion base aft of the mast and the third to mast cleats about breast high. The three legs intersect on a plane with the mast base where it pivots. Make it out of appropriately strong line and make at least one of the legs adjustable on each side. It is a lot easier to stow than a rigid a frame and much easier to construct. And I would suggest using this or some other form of mechanical aid even if you do have enough man power to do without. People tend to let go of things at the most inopportune times. :eek:

Oh, and I use my jib halyard in conjunction with a gin pole and block and tackle (my soft boom vang) to lower and raise the mast.

SHNOOL 09-15-2011 04:59 PM

You guys have me wondering if my A-frame might be better built with just 2 pieces of lumber, and bolts/straps around my stantions to keep them from kicking out/moving. Hmmm. Gears grinding now. I'll take a picture, since I have to do it this weekend, and let you know how I did.

By the way, we got the mast up, just the 2 of us... but first me lifting it and placing it on the end of a 4x4 post with a yoke on it (8 feet up).. Meanwhile the mate grabbed the jib halyard (or was it spinnaker - no matter) and she yanked on the halyard as I aped the mast up. My boat is shorter than yours, but has a relatively heavy mast for it's size.

This worked, but our first attempt resulted in me letting it lose, and nearly getting slammed by the mast as it fell down onto the stern lifeline, pulling my poor wife halyard, rope burn and all.

I am REQUIRED to come up with a better way then that, she banged her arm good on the bow pulpit, and had significant rope burns. Meanwhile my shoulder was bruised and I darned near got smashed by a VERY expensive mast (mast survived nicely).

Izzy1414 09-16-2011 12:11 AM

Just fo be clear (or at least clearer), my system has no lumber at all, just rope and nylon webbing (tie down straps for the upper adjustable legs). No need for any ridgidity as all legs of the bridle are in tension.

cdhickey 09-16-2011 10:03 AM

Thanks for the comments! Lots of things to think about there. I think i'm going to go ahead with the bridles for extra support at least until I get a feel for stepping and unstepping. I'll try to take a few pictures of my final setup and post them if not too embarrassing.


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