Hello,

I would be interested to know if anyone has a baseline rigging tension for SS26 they could pass on. I have found some general guidelines on the internet they may suffice if not. Thank you.

Clare

Hi,

I can't remember the exact settings I use off the top of my head, but I know that in order to stop the leeward shroud(s) going slack when really hard on the wind they need to be tighter than you might imagine.

The shrouds on Evangeline (SS No.97) are 5mm, and thinking about it I'm pretty sure the caps are set up to around 18-20% breaking strain, which is close to the absolute maximum you should ever use. The lowers are slightly less. The forestay can be anything from 10% to 22% depending on how much backstay is applied. The backstay is marked to prevent me over over tightening the forestay.

If you are setting up the rig from scratch I would strongly suggest investing in a rig tension gauge. I have a Loos type PT-2 and can't really recommend it highly enough. They seem stupidly expensive for what you get, but if your mast goes up and down annually (as mine has to) you really will appreciate it. Also, "Illustrated sail and Rig Tuning" by Ivor Dedekam (published by Fernhurst Books) is a great book that takes away a lot of the mystery of rig/sail tuning. Armed with the book and a tension gauge setting up the rig is really very straight forward

Hope this helps. If you would like me to actually measure my rig, let me know.

Regards

John

John Guess
SS26 Evangeline

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Hi Clare

I haven’t had my boat long and initially just set the mast up to marks left on the rigging screws by the previous owner. Generally it seemed OK, the mast was about straight sideways but the forestay seemed a bit saggy and I appeared to get better main sail shape on a Port tack than on STBD, so some tweaking was in order, but I needed to start from a known point so decided to re-tune from scratch – this is what I did.

http://www.seldenmast.co...?id=6740&randnum=4379830  gives some good tips on the tensioning by measurement method. However you do need a couple of bits of information on the set up to get you started.

The first is mast rake, the sail and rig tuning book suggests a figure of 2-3 deg. Literature for the SS27 suggests setting the mast so it’s almost vertical with a slight aft rake but I haven’t been able to find an actual figure. There is limited info on other fractional rig boats to compare with but that I have found seems to suggest 2 degs is the norm. On the SS26 2 degs gives a distance of 317 mm along the boom (distance b in the sail and rig tuning book). On ‘Calypso’ with the shrouds hand tight and the backstay off the measured distance was about 320 mm, so I didn’t need to adjust this.

Using a tape measure and a short rule I tuned the cap (upper) shrouds first to 20%. At this the forestay still seemed a little saggy so decided to increase to 25%.

The second input is pre-bend, the sail and rig tuning book suggests 30 – 50 mm, info for other fractional rigged boats is in the range of 60 – 80 mm and literature for the SS27 suggests a pre-bend of 2-3 inches (50 – 75 mm). Before starting the re-tune, with the shrouds still tight and the back stay hand tight, the pre-bend on ‘Calypso’ was about 2 inches, so again in the right ball park.

After I had tensioned the cap shrouds during the re-tune I measured the bend at about 4 – 5 inches, I then tuned back to 2 inches using the lowers.

I have yet to check the tuning under sail as I ran out of time, but I will update when I can.


Jon Foreman
Calypso

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It been a while since the re-tuning outlined above but I haven’t really had the chance to test under the right conditions until recently.

When sailing at around 20 deg heel the leeward inner shrouds were very slack and the boat just wouldn’t point, very disappointing! So I got hold of a Loos tension gauge (PT-2M) and checked the shroud tensions using this and found both the inners and outers to be slacker than I thought. I re-tensioned to 37/38 on the outers and 34/35 on the inners with 2 inches of pre-bend. I have 6 mm shrouds which I think is larger than normal so these readings equate to about 20 - 22% and 14 – 16 % of the breaking strain. Tested again and she performed significantly better and the leeward shrouds seemed OK.


Jon Foreman
Calypso SS26, no.96

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