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Author Topic: Mainsheet Post on an IOM help needed  (Read 3670 times)

andrewa

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Mainsheet Post on an IOM help needed
« on: March 29, 2010, 09:52:26 AM »

Hi All,

I got a generic deck kit hardware pack the other day which included a mainsheet post and Im a little unsure how to rig the lines to it.

Can anybody who uses one please post a picture of theirs showing the rigging so I can see what on earth I am supposed to with it please? :)

Also, how far back from the mast should it be? Does that matter?

The post itself is height adjustable as it is just two aluminium tubes, one inside the other which slide freely. Should this be epoxied at roughly the correct height or do I just let it slide up and down?

Cheers,
Andy
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tony52

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Re: Mainsheet Post on an IOM help needed
« Reply #1 on: March 29, 2010, 02:12:07 PM »

Andy,

A good starter for rigging an IOM is to obtain a copy of the plans for 'Rythym' by Graham Bantock. Available from www.myhobbystore.com plan MM1466. Sometimes appears on ebay

Just a thought,
Tony.
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MikeK

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Re: Mainsheet Post on an IOM help needed
« Reply #2 on: March 29, 2010, 09:45:44 PM »

Hi, it's all a bit of a juggling act really !! The distance between the boom pivot and the sheeting point on the boom should be such that the travel of your winch from full in to full out will cause the boom to go from just off centre (close hauled) to right out almost touching the mast stay. A bit of the old Pythagoras with the length of your winch run as the Hypotenuse and the other two sides as the boom length from pivot to sheeting attachment point at full in and full out (for the sake of argument take it as 90 deg boom travel ) Once you have that length this will dictate the position of your sheeting post. Depending on the deck configuration it may be upright or angled so that the sheeting outlet is underneath the sheeting point on the boom and of such height to be just below the boom so that the winch pulls horizontal and not down towards the deck, that's why the telescopic tubes are there for height adjustment Of course all three or more sets of sails will have their sheeting points the same distance along the boom as well. Another way I suppose is to get a piece of string equivalent to your winch run, put the mast and boom in the deck, and by trial and error run string with one end held to the stay and slide the other end along the boom until taut which will give you the sheet attachment point minus boring geometry  :-))
I'm sure there are on line articles somewhere that can explain things better than above but at least it gives you something to work with, now what was it again the sum of something is equal to ahh 'xxx' it !!  {-) {-)

Mike  
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MikeK

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Re: Mainsheet Post on an IOM help needed
« Reply #3 on: March 30, 2010, 09:28:29 AM »

Went to sleep last night trying to remember the mathematical way I mentioned - good way of getting of to sleep quickly ! - came to the conclusion the bit of string method much more user friendly  O0 (as an update on the string method the boom would be held just off the centre line in the close hauled position)

Mike
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Islander1951

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Re: Mainsheet Post on an IOM help needed
« Reply #4 on: March 30, 2010, 10:01:17 AM »

If you want some Math, have a look here:

http://onemetre.net/Build/Sheeting/Sheeting.htm

Lester's site can tell you anything you want to know about IOMs as far as theory goes.

              Edward.
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MikeK

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Re: Mainsheet Post on an IOM help needed
« Reply #5 on: March 30, 2010, 04:55:29 PM »

Makes my bit of string look a bit stone age   %% %)

Mike
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dreadnought72

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Re: Mainsheet Post on an IOM help needed
« Reply #6 on: March 30, 2010, 05:23:11 PM »

Don't worry about it, Mike. Stonehenge and the pyramids didn't need no fancy Excel spreadsheets and diagrams, and they're still (more or less) standing!

(Though I do like the depth of the mathematical approach shown on that link.)

Andy
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Enjoying every minute sailing W9465 Mertensia

MikeK

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Re: Mainsheet Post on an IOM help needed
« Reply #7 on: March 30, 2010, 10:21:49 PM »

Secretly, so do I Andy, but don't let on !  ;) ;)

Mike
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