Hi
I'm setting up my rigging for the first time after replacing one of the shrouds and raising the mast. I have followed the directions in the Parker manual and referenced Ivan Dedekam's book and set up using a Loos PT-1M gauge.

I have assumed that the forestay is the correct length as it is the original. I have set the shrouds to 35 on the Loos scale which gives 15% of breaking point which is well within the recommended of 20% for 4mm wire. With this I have set the lowers to 31 on the Loos scale (12% of breaking point) again within the recommended breaking stain. This gives a mast bend of around 50 - 70mm (hard to measure half way up the mast). The forestay still has plenty of play

I could tighten the lowers or loosen the shrouds to reduce the mast bend but I would like to know the experiences and advice of other owners in tuning the rigging.

Many thanks
Andy

Jago
Parker 235/04

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Hello Andy,

I’m not sure whether the gauge readings will be the same as mine because yours is the ‘pro’ version and I have the basic one. However, I believe you will find 15% to be insufficient tension in the cap shrouds to prevent the leeward ones going slack while beating.

The amount of mast bend you want will depend on how worn/full your mainsail is.


Anthony Russell
235/02 Sea Wyche

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Hi Anthony

Thanks for the reply. I think that both types of gauge will read roughly the same and assuming that the shrouds are the around the specified length 15% sounds like a good starting point for me. What tension are your lowers?

Andy


Jago
Parker 235/04

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I think I had the lowers at about 16% (with the backstay off - they tighten a bit as you pull the backstay on, while the caps slacken.) I intend to use more pre-bend this season, though, and to experiment with forestay tension because I've bought a new jib.

Anthony Russell
235/02 Sea Wyche

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Hi Anthony

I think I need to tighten up my lowers which should reduce the mast bend down to the recommended 25mm - 50mm.

Using the calculations in Ivan Dedekam's book I should be able to adjust the back stay to get a target of 44cm of rake based on a mainsail length (p) of 8.382m (27.5 ft)for upwind. BUt I will check the tensions when this is set to ensure I don't exceed 20%

Of course this is the theory which will need to be checked out on the water.

Sounds like you will be having fun with the new jib. I would be interested to know the level of improvement it brings to your 235.

Andy

Jago
Parker 235/04

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Andy,

As you say, the main test is on the water, to check that the leeward shrouds don't go slack - especially with the backstay on. I found I had to tighten the caps a bit more for that. (Note that the recommended not-to-exceed tension for this type of rig is 25%, with 20% being the recommended starting point for the cap shrouds.)

I'm expecting good things from the new jib because the old one was well past its best. Looking forward to it!

Anthony Russell
235/02 Sea Wyche

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