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Nova 28


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I thought the idea was to buy another boat, then think long and hard about selling the old one, or maybe put it in another harbour/country? Seems most of us have far too many boats these days- if that's possible

That's one way, I try to do it on the sensible way if we can say sensible in  this case.

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Query about Novas and rig tension/tuning, and this seems as good a place as any!

 

I'm helping a friend get a Nova ready for summer (his first summer), and want to tune the rig.  Does anybody know what sort of tension we should be looking at on caps and on lowers?  Are they run fairly slack or...?

 

Thanks in advance for any info.

 

Cheers

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No boat should have slack rigging - it induces shock loading and is not what the designer intended.

Short of any specific class setup (which imo you are unlikely to get), start here.

 

Mast rake at 3 deg. Caps at 15-20% of Break Load. Forestay/backstay at 20%. Lowers should induce about 1/2 of mast diameter pre-bend, and sufficient tension to keep the mast in column when fully powered.

 

If you start there, you wont be far out.

 

Great setup in in Ivar Dedekams book "sail and rig tuning"  - tells you why the above is good, how to set up tensions without gauges, etc. A good guide all boat owners should have. IMO. 

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No boat should have slack rigging - it induces shock loading and is not what the designer intended.

Short of any specific class setup (which imo you are unlikely to get), start here.

 

Mast rake at 3 deg. Caps at 15-20% of Break Load. Forestay/backstay at 20%. Lowers should induce about 1/2 of mast diameter pre-bend, and sufficient tension to keep the mast in column when fully powered.

 

If you start there, you wont be far out.

 

Great setup in in Ivar Dedekams book "sail and rig tuning"  - tells you why the above is good, how to set up tensions without gauges, etc. A good guide all boat owners should have. IMO. 

 

IT is correct, I don"t think you can get Nova specific advise, as so many variant around and seems all builder, home builder had different opinion (or resources). One thing which could be an option to find someone with the original design package that may have a rigging section.

 

I tried to set my rig earlier and i couldn't create any band on the mast, even when I over tightened some of the shrouds, and the back stay. It feels like my mast is well over sized compare to the height, so I gave up to get any pre-bend. Is it bad?

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All boats should have some pre bend. How you get it depends on the rig type. For example, on a single straight spreader Masthead rig with fore and aft lowers, set rake, ensure mast is upright, set cap shroud tensions, then tighten forward lowers (slack aft lowers) until correct pre bend is achieved. Then tighten aft lowers until firm. Check tensions under sail (pre bend remains, mast in column etc)

If you are doing this yourself, I strongly suggest the assistance of the book I mentioned above.

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I tried the same method (description came from somewhere else but exactly the same) and I the tension on the forward shrouds was quite substantial and I had only a couple of mm bend (virtually nothing)  my mast is 125x215 mm (I don't know if it will refer to inches). I fixed a number of problems back then, like I had no rake at all, also the mast was offset to port side about 55mm. 

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Is it deck or keel stepped? If keel stepped, the partners must be removed first, or you could s bend the mast, which is BAD. Either get a rigger to set it up, or get the book.

You can tell how much load on a shroud by its elongation over a set length. Most people severely underestimate shroud loads.

Prebend should be from heel to head, not deck to head! Any mast will quite easily bend to about 1/2 it's diameter, if something is not stopping it. However, due to the narrow angle of many fwd lowers, it can take a bit of load to do it. Should not be more than 15-20 % of b/l though.

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