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Harken Magic Box

9K views 5 replies 3 participants last post by  mikehoyt 
#1 ·
On my boat there is a Harken Magic Box attached to the end of the boom for outhaul adjustment. It seems to work well with mechanical advantage for tightening the outhaul but will only ease outhaul when there is a significant load on the main.

Does anybody have experience with these? Do they need assistence when easing the outhaul or does this device need to be taken apart and lubricated?

Thanks

Mike
 
#2 ·
Spraying the thing in appropriate places with a lubricant may help. It''s likely just the friction of all the lines and sheaves in that tiny space rubbing against each other that''s keeping it from easing out. We had one for the jib halyard on our Soling - plenty of load, so no problem easing, but the ratio is on the order of 12:1.
 
#3 ·
I have had one on my O''Day30 for about 12 years and love it. it has a lot of purchase and am able to easilly flatten main on the wind no matter how hard its blowing. this is very important. to ease it if there''s load on the main it will ease fairlly easily. if not loaded you will have to pull on the foot to get it eased. i found on mine that it does ease without as much friction when i bought my loose footed main. it will work easier if the slide in the boom is lubed. since it has such a high purchase there will be some res to easing since there has to be so much line to move in the box relative to the amount on movement in the foot of the main. possibly you could attach a piece of heavy bungy to the clew to help it slide back. I''ve never found the res to be a problem. to me its always been a bigger problem on other boats that don''t have any purchase and you have to ease the mainsheet and drop the main to leeward some to get the main flattened. if you race this can be a big deal.
 
#4 ·
Thanks.

I used bicycle chain oil on the gears inside the box and it works quite well. My only gripe is that it eases well in heavier winds but not so well in light winds when you want it eased. The lug in the track for loose footed main has been noted and was on my to do list for Sunday but somehow overlooked. It seems the lug tends to not always be perfectly level in relation to the boom and can have some resistence,

Thanks

Mike
 
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