I own a 1973 Venture 224 which I have modified to a masthead rig. I am trying to adjust the upper and lower shrouds so that the mast will not have any bend in it. I have borrowed a tension meter and need to know how many lbs. of tension to adjust the shrouds to.
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shrouds
tension is gen. 10 to 15% of working load of wire. would recommend using loads from origional stay size since the mounts would be rated for the smaller workload wire. check a west cat. for working load of the shroud materials, prob 1/8 inch when new. most tighten the upper/outers first then the inners.
tension is gen. 10 to 15% of working load of wire. would recommend using loads from origional stay size since the mounts would be rated for the smaller workload wire. check a west cat. for working load of the shroud materials, prob 1/8 inch when new. most tighten the upper/outers first then the inners.
Loos Gauge
Bruce sounds like he's turned a buckle or two. Here's a site for help. http://www.loosnaples.com/howto/90-91gauges.htm Steve P.
Bruce sounds like he's turned a buckle or two. Here's a site for help. http://www.loosnaples.com/howto/90-91gauges.htm Steve P.
My grateful "Thanks" to Steve Paul and Bruce for the reply to my question. I have borrowed a Loos PT-1 tension gauge and the information provided will be a great help in adjusting my shrouds. Again, many thanks. Rai
You are welcom !
I must say I read through the Loos site and learned a few things myself. I own a loos gauge and have read the manual but the web site is a must read before attacking the wires. Steve P.
I must say I read through the Loos site and learned a few things myself. I own a loos gauge and have read the manual but the web site is a must read before attacking the wires. Steve P.
tension class 102
So if I can take this discussion a little further; The Mac rigging instructions say to have an initial slight bend (not rake) in the mast. In a fractional rig, I'm guessing that the forestay produces much of this bend is that right? I have a new adjustable backstay. My "duh" question is how do I rig it? I mean should it be used only to introduce more bend or do I compensate the tension in the forestay so that the backstay produces the initial bend. Theoretically that would give me more range right? Enquiring minds want to know. Thanks for your patience.
So if I can take this discussion a little further; The Mac rigging instructions say to have an initial slight bend (not rake) in the mast. In a fractional rig, I'm guessing that the forestay produces much of this bend is that right? I have a new adjustable backstay. My "duh" question is how do I rig it? I mean should it be used only to introduce more bend or do I compensate the tension in the forestay so that the backstay produces the initial bend. Theoretically that would give me more range right? Enquiring minds want to know. Thanks for your patience.
mastbend
the bend is to get a better fit of the sail to the mast, to prebend may not fit the sail shape. the bend is made with the aft stay, but only as much as needed to get the proper shape and power out if the main. good luck.
the bend is to get a better fit of the sail to the mast, to prebend may not fit the sail shape. the bend is made with the aft stay, but only as much as needed to get the proper shape and power out if the main. good luck.
adjustment article
A good article by a fellow Mac owner. This is the part that particularly talked about mast bend. "Keep in mind that on a fractional rigged boat, an adjustable backstay will only bend the top of the mast, so don't rely on it for all of your mast bend under sail. Instead, induce some bend using the rigging, and use the adjustable backstay to get a little additional bend when needed."
A good article by a fellow Mac owner. This is the part that particularly talked about mast bend. "Keep in mind that on a fractional rigged boat, an adjustable backstay will only bend the top of the mast, so don't rely on it for all of your mast bend under sail. Instead, induce some bend using the rigging, and use the adjustable backstay to get a little additional bend when needed."
masthead
sorry i missed the masthead part, any bend needed will have to come from a inner forstay, which you don't have. to balance the boat, the mast may be angled aft or forward using the mast heads fore/aft mast head stays. the 'bend' used in a fractional rig will prob be impossible to get. if you order a new main, be sure to tell the maker that you have changed to masthead so they can cut the main to fit properly. i have a mac 23 cutter that i converted to masthead.
sorry i missed the masthead part, any bend needed will have to come from a inner forstay, which you don't have. to balance the boat, the mast may be angled aft or forward using the mast heads fore/aft mast head stays. the 'bend' used in a fractional rig will prob be impossible to get. if you order a new main, be sure to tell the maker that you have changed to masthead so they can cut the main to fit properly. i have a mac 23 cutter that i converted to masthead.
Loos numbers
I used Loos 25 for tension on all stays and it seemed to work fine. I usd the scientific method of 20 being too loose, and much more than 25 seemed to add too much mastbend. I use Loos 30-35 for the forestay on a different class boat that requires this higher tension to introduce prebend into the mast. I didn't think the Mac would need as much tension.
I used Loos 25 for tension on all stays and it seemed to work fine. I usd the scientific method of 20 being too loose, and much more than 25 seemed to add too much mastbend. I use Loos 30-35 for the forestay on a different class boat that requires this higher tension to introduce prebend into the mast. I didn't think the Mac would need as much tension.
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