49er rigging problem

feffe

New member
18
1
Ciao a tutti!

I've recently switched from an old 49er to a newer one with the full carbon rig.

I am finding hard rigging the mast in a correct way and I would need some suggestions to fit it better.

I am feeling that the mast has a too costant bending curve instead of having the bottom section more straight vertical and the top section more bented. Actual tensions seem sensible and are:

- Forestay 29

- Lowers 20

- Shrouds 31

- Uppers 19

You can find attached a side view of the boat to see the rigged mast profile.

WhatsApp Image 2021-08-28 at 20.14.54.jpeg

I am also thinking that the head of the mast is way too backward because the kite has too tension on the luff. The actual rake measure is 849cm (from mast head to the bottom back of the hull).

Maybe the forestay is too long? Its actual length is approx. 642.5cm (from bottom pin axis to the corner of the top fitting). Should this be its proper length?

What do you think?

Thanks you all!!

Federico

 

allweather

Member
400
80
baltic
With a little luck we're having Julian in here soon to give the cliff notes. Until then I asked similar questions before.

Second post outlines how the 49er usually measures prebend/rake with the jib halyard.(that is where you'll get the references for)
Usually forestay is within ranges and doesn't deviate much at all. Could be though.(I once mistook an old rig forestay with a new one. 1-2cm difference!)

About curve, that doesn't actually looks too bad overall. Does it feel bad while sailing? Not depowering smoothly or other issues?

 

JulianB

Super Anarchist
1,045
1,308
Sydney mostly
Hi Guys, a 49er forestay is nominally about that length, it is never measured trhat way.

What they do is they measure how far it extends past the mast plug, from memory it's 425-435mm from the bottom of the mast plug tallon, (the bit that sits in the mast-step,) to the the BP of the forestay toggle, so that is the top of the M6 pin.

It's all on the WS web-site, you can go in via worldsailing.org or go into 49er.org and follow the links.

But 6425mm, I don't actually have the number of the SS mast handy, so I can't be definative,  but it is likely to be within 10mm of correct.

The bend, I would straighten up the lower part of the mast with more D1 (lowers tension) a) it's to bent, needs some bend but noth that much & b) and for your first sails that will induce more bend up high and that's a good thing.     As you get more and more competent you start easing the Caps (M2.5 wires going to the top) and that will give you more power.      But 49ers bite the un-trained so less power is good initially.

Re the spinnaker, you could very easily have a pre-2012 spinnaker.   When we put the Carbon mast (2008) on we extended it 170mm so as not to have fly weights sailing the boat.    Got that number near perfect and initially the spinnaker halyard was feed down to a "snotter" about 150mm down from the tip so the pre 2012 worked.

Post London, there was a new spin design that went all the way to the top, so if you have a pre2012 spinnaker, it will be tight luffed.

Just tie a knot in the Halyard, say 100mm from the end, you can do the same thing in the Brace/Tack line.

While in knot tying mood, tie a knot in the mainsheet so the boom CAN'T  hit the shroud.  Give yourself 150mm comfort zone, boom never goes out that far anyway.   Biggest error is to let the mainsheet go and the boom hit the shroud, cantalivers, and drives the GN backwards and down come the mast with a lots of tears

Most importantly, have fun, wish I was still fit enough to sail one, they are great fun just hooting around.

                 jB

 

JulianB

Super Anarchist
1,045
1,308
Sydney mostly
BTW, rig tensions

D1's too loose

Main shrouds to tight,

The rest is OK.

Dont let the caps (uppers) go below 17, it become marginal.

 

feffe

New member
18
1
With a little luck we're having Julian in here soon to give the cliff notes. Until then I asked similar questions before.

Second post outlines how the 49er usually measures prebend/rake with the jib halyard.(that is where you'll get the references for)
Usually forestay is within ranges and doesn't deviate much at all. Could be though.(I once mistook an old rig forestay with a new one. 1-2cm difference!)

About curve, that doesn't actually looks too bad overall. Does it feel bad while sailing? Not depowering smoothly or other issues?
Actually I've just sailed it once with 8-12kts and the main issue is while sailing downwind the kite too nervous and unstable due to the excess of luff tension. But as @JulianB says this is most likely related to the old style kite fitted up to the mast head.

 

feffe

New member
18
1
Hi Guys, a 49er forestay is nominally about that length, it is never measured trhat way.

What they do is they measure how far it extends past the mast plug, from memory it's 425-435mm from the bottom of the mast plug tallon, (the bit that sits in the mast-step,) to the the BP of the forestay toggle, so that is the top of the M6 pin.
I checked the FS length in the proper way and it is more or less 432mm. So we can assume that it is OK.

BTW, rig tensions

D1's too loose

Main shrouds to tight,

The rest is OK.

Dont let the caps (uppers) go below 17, it become marginal.
I try make this changes this afternoon! Can I go up more than 20 with D1's tension?

I have noticed that my mast foot is approx 10mm more forward than another Mackay 49er (the pin hole for the mast foot is heavily ovalized and has a slightly different position). Moving back tha mast foot a bit can help or it is not really helpful?

Re the spinnaker, you could very easily have a pre-2012 spinnaker.   When we put the Carbon mast (2008) on we extended it 170mm so as not to have fly weights sailing the boat.    Got that number near perfect and initially the spinnaker halyard was feed down to a "snotter" about 150mm down from the tip so the pre 2012 worked.

Post London, there was a new spin design that went all the way to the top, so if you have a pre2012 spinnaker, it will be tight luffed.

Just tie a knot in the Halyard, say 100mm from the end, you can do the same thing in the Brace/Tack line.

While in knot tying mood, tie a knot in the mainsheet so the boom CAN'T  hit the shroud.  Give yourself 150mm comfort zone, boom never goes out that far anyway.   Biggest error is to let the mainsheet go and the boom hit the shroud, cantalivers, and drives the GN backwards and down come the mast with a lots of tears

This makes really sense! I will check my kite manufacturing date but I should have something newer and I will try with that. Thanks for the mainsheet knot advise, is always nice knowing kind of this tips before it is too late :D

Fede

 

allweather

Member
400
80
baltic
While in knot tying mood, tie a knot in the mainsheet so the boom CAN'T  hit the shroud.  Give yourself 150mm comfort zone, boom never goes out that far anyway.   Biggest error is to let the mainsheet go and the boom hit the shroud, cantalivers, and drives the GN backwards and down come the mast with a lots of tears
Oh that is very good detail to know. Always had the knot "since one never sheets out that far anyway" but I also always worry about the mast remaining standing so anything against that is nice to know!

 

JulianB

Super Anarchist
1,045
1,308
Sydney mostly
I have know lowers to be up in the low 30's, but it will also depend on primary stay tension.

As long as the mast has a positive bend, then there is no "you cant exceed this" number.

The 17 on the caps, FX go down to 14-15, but they make sure the mainsheet never goes out, so the leach acts as a backstay.

Enjoy your Sunday,    jB

 

feffe

New member
18
1
Thanks @JulianB and @allweather

And what do you think guys aboout moving the mast foot a bit rearward? I have a spare new mast foot plate and replacing my actual with that the mast base would move approx. 10mm rearward. Is this sensible or not? (checking the distance between the mast front face and the jib rail mine is more close than an other 49er that I mesaured last weekend).

Fede

 

JulianB

Super Anarchist
1,045
1,308
Sydney mostly
Mast heel position is all to do with D1 tension.

10mm in 5000mm is 0.2%, unless your chasing Gold then it's irelevant!

              jB

 

Juani-S

New member
I have know lowers to be up in the low 30's, but it will also depend on primary stay tension.

As long as the mast has a positive bend, then there is no "you cant exceed this" number.

The 17 on the caps, FX go down to 14-15, but they make sure the mainsheet never goes out, so the leach acts as a backstay.

Enjoy your Sunday,    jB
Hi! 

There is a lot of game with the caps on the 49er (big diff with the Fx)... you can just loose one point or get it one point more with the fast pin. The key is to see your main and feel the boat. We tested also to get ride off the screw of the mast and get a little game on the top of the mast, but I also know people that are putting glue to avoid any movement... 

Regarding the D1; it also depends on the stiff your base section is and the mm of the wire you use. 

One thing is always getting me in doubt is the angle of the mast step regarding the bracket and the hull... is importante to keep and take car the mast step on the outside and on the inside with the carbon fiber of the mast. 

Hope this will come better in the new mast! 

Cheers. 

 

Grandaddy

New member
5
1
Brisbane
I am also rigging a 49er with new style rig but earlier model sliding wing hull. Seems to have most of the go fast ‘soft shackles’ and spliced lines, extra block in jib sheet etc but the wings and hull needed work. I’ll have completed this soon and will be ready to re-fit it. If anyone wants to help?

 
I am also rigging a 49er with new style rig but earlier model sliding wing hull. Seems to have most of the go fast ‘soft shackles’ and spliced lines, extra block in jib sheet etc but the wings and hull needed work. I’ll have completed this soon and will be ready to re-fit it. If anyone wants to help?
Just make sure the wing slider riverts are not damaged or corroded and just replace all the shockcord under the wind and your set, If theres damage to the actual fibreglass you would just do a normal repair and add some sort of grip (something like quick grip with sand or something).

My boat recently got blown in a storm so im trying to fix all the holes in it now.

 

feffe

New member
18
1
Dear guys,

after some attempts the rig set up improved. The main sail shape seems fine and it get hoisted pretty smooth. The mast bent curve matches the main luff and the controls lines work nice as well to flatten the sail.

But I still have issues with the kite. While sailing downwind It is really nervous and when it starts collapsing from the luff there is no way to save it (or it is really hard).

I still have some doubts about the correct luff tension for the kite. How can I mesaure it or is there a reference to know if mine is more or less fine? The kite I am using now is a post-2012, so it should be fine fully rigged up on the mast.

Anyone with some tips/ideas?

I would like to know some reference numbers to check my mast rake and how much the spinnaker pole should sticking out from the front of the boat.

@JulianB maybe you have some numbers to share?

Grazie!

 

JulianB

Super Anarchist
1,045
1,308
Sydney mostly
So your using a 10 year old spinnaker.

Highly probably the luff has stretched and that has made the spinnaker "nervous ".

99% of people look at the luff line and shrug their shoulders, so there is a very high probability that one of the previous owners of the spinnaker did just that.

There is probably a 5% chance that tweaking luff line tension will rectify the issue, again it's a 10 year old spinnaker, regardless its worth the try.

1st thing to do is find a reference point.

fix the head of the spinnaker to something solid, I use a railing, then undo the luff line and extend the spinnaker so you can apply some tension to the luff of the spinnaker. Do that, anything from about 7 -10 kgs is fine. (Spinnaker has 4-5 times that load in use).

While under that load, secure the spinnaker ( I put a clamp on the railing, on the luff tape)

then apply exactly the same load to the luff line, same direction, yad yad.

When you confident that you have same tension in both the luff and the line, use a marking pen and reference the luff line against the luff. Do it about 1/2 way between the opening and the grommet.

Un- clamp everything and then tie the luffline at your reference point, go sailing.

like that the luff line will be taking equal load to the spinnaker. If the luff is too round, ease it 20mm and go trialing again.  If it lays off too much (& that makes it nervous) tighten it 20mm. Trial again. 

Nothing stopping you doing this on the water, do a change, trial it, then tweak again.

but 10 years is a long time for any sail

 
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