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Old 18-04-2012, 19:04   #1
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Need advise on Boom Control rigging

Im in the process of installing winches and running rigging on a very bare bones boat. She's 42 feet long. I need some advise on how to rig the boom control. I've seen the common two standing blocks on port and starboard along with the block on the boom. But I'm wondering if there is a simpler way to control the boom. BTW it's a pilothouse sailboat. I don't want to put more holes in the deck or pilothouse roof hence don't want to add two stand up blocks. I've attached a picture. A bad one at that but you can recognize a very large cleat eye dead center. The boom lays on a single gallo. The boom is raised and held by the mainsail itself as per the previous owner. Can I rig this control with a block on the boom and a block attached to the huge cleat eye? I've tried researching this all over but can't find any simple rigging methods. Help me out here I'm a total newbie. What 's the best way?? Thanks!!!
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Old 18-04-2012, 20:12   #2
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Re: Need advise on Boom Control rigging

G'Day KD,

Your nomenclature is a bit vague, but I think that you are asking about the main sheet. That is the line that controls how far out the boom can travel, and hence controls the angle of the mainsail relative to the wind, and also to some degree the amount of twist in the sail.

On a 42 foot boat, the mainsail is pretty big, and generates a lot of force, even in moderate winds. You need to be able to pull it in against all that force, and the tackle that you describe (basically a 1:1 purchase if I followed you correctly) is nowhere near powerful enough. On boats that size a typical setup would have something on the order of 4:1 purchase with the tail lead to a winch as well.

I humbly suggest that you read up on this a bit before you commit to buying blocks, etc. The Harken catalog has diagrams of various systems, many of which are quite complicated, but they should help you understand what you are up against. Any basic sailing book will also show some simple arrangements. Further, have a look around at how other boats of similar size are rigged. I doubt if you will find any with a system as simple as what you are contemplating.

Good luck,

Jim
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Old 18-04-2012, 20:17   #3
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Re: Need advise on Boom Control rigging

I think you will need an easily adjustable vang on the boom...to hold it down as the sheet is eased.
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Old 18-04-2012, 21:33   #4
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Originally Posted by KeysDreaming
Im in the process of installing winches and running rigging on a very bare bones boat. She's 42 feet long. I need some advise on how to rig the boom control. I've seen the common two standing blocks on port and starboard along with the block on the boom. But I'm wondering if there is a simpler way to control the boom. BTW it's a pilothouse sailboat. I don't want to put more holes in the deck or pilothouse roof hence don't want to add two stand up blocks. I've attached a picture. A bad one at that but you can recognize a very large cleat eye dead center. The boom lays on a single gallo. The boom is raised and held by the mainsail itself as per the previous owner. Can I rig this control with a block on the boom and a block attached to the huge cleat eye? I've tried researching this all over but can't find any simple rigging methods. Help me out here I'm a total newbie. What 's the best way?? Thanks!!!
What you are contemplating is more the set up for smaller boats where the blocks and jammer are integral to the mainsheeting system. Photo one shows a 4:1 system (probably small dinghy/keelboat) and this is how my 26 footer is set up. Photo two shows 8:1 (likely a beach cat) where sheet loads are higher. It is verry difficult to use these with a winch.

The disadvantage is lots of main sheet needs to be pulled through. Could work on your boat but 40+ foot boats produce high loads.

The third photo is more typical of big boats. The sheeting system is run forward, then base of the mast and back to a winch. This photo also shows a traveler system as opposed to your single point of attachement. Single attach points are seen on non performance boats as with no traveler you have fewer sheeting control options.

This photo also does not show a spinlock or cleat just ahead of the winch which is typical for locking down the sheet.

You did not mention a boom vang. This is used to prevent the boom from rising as you sheet out the main sheet.

So in a pinch you could go with 8:1 center sheeting self locking (I think 4:1 on 40 feet wont work) or invest in a complete set of controls that includes boom vang, traveler, main sheet system run to the mast, spinlock clutch and winch.
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Old 18-04-2012, 22:06   #5
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Re: Need advise on Boom Control rigging

I agree with what has been said so far. I'd like to add something that hasn't been said so far, and which, as a total newbie, you need to learn:

Not only are the forces on a mainsail large and hard to handle unless you have adequate gear, they are dangerous to you and to your boat and - most importantly - to your crew.

Most of the old hands here don't often get questions quite so basic with quite so totally newbie questioners. They've given you very good answers to your question. My thoughts aren't so much directed to your question as to much more gritty considerations. Events in San Francisco this past weekend show that even very experienced and very capable sailors can be lost when Mother Nature cuts loose.

When you look at a few books you'll get the idea of the forces involved and learn to treat them with considerable respect and care. I would also suggest that you get down to the dock and volunteer as crew on some other boats and get yourself some basic experience. Lots of folks need crew, and if you ask, they'll be a good resource and get you going.

Good luck, stay safe. Fair winds and following seas.
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Old 19-04-2012, 06:24   #6
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Thank you all for the great direction and advise. And yes, safety is the first consideration as well. All the best...
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