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Sail & Rigging - Swan 41 new rig
12 October 2012 - 08:58
#1
Join Date: 01 January 2011
Posts: 36

Swan 41 new rig
May I ask the Forums advice on how to choose / specify / ask for quotes on a new rig for Scotch Bonnet? Some of the things I think I need to look out for are: mast needs to be tapered, it should be anodised, ideally made in 1 piece and not 2 pieces joined, need to think about reefing system, need to decide how and where to replace the halyard winches, need spinnaker pole, there were some features on the original rig like an internal line for running a replacement halyard but what other areas if I pay attention to detail should I specify up front? Do I need to worry about the type/thickness of the alloy or is it standard? Type of track? Separate track for the trysail or rely on gate as original. Then questions on vangs, furlers, etc. If anyone has experience with this type of project would very much appreciate any guidance and advice on best options when starting with a completely blank canvas! Thanks and regards, Andrew Scotch Bonnet 41/039

13 October 2012 - 12:05
#2
Join Date: 02 January 2008
Posts: 1547

Dear Andrew
The spar builder basically needs the sail and rig dimensions including chainplate positions and bury, number of spreaders, stability information for the yacht, and the type of sailing you do. This enables a mast section to be chosen from the selection available.
If the builder can come to the yacht and take measurements this is preferable.
In addition to that you should describe all the details you consider important, but finally it is the quoted specification as well as the builders practice which defines what you will get. It is worthwhile making sure that you get a complete spec containing your requirements, and it would be good to inspect a rig from this builder.
Referring to your wish to get a one-piece anodized section, pls note that this requires an anodizing tank longer than the mast, and they are scarce.
Kind regards
Lars

16 October 2012 - 11:54
#3
Join Date: 01 January 2011
Posts: 36

Dear Lars, thank you for your advice. I've spoken to a rigging company who ask for "the moment of the mast and boom" in order to decide the choice of section. Are you able to tell me this please? You mention also the stability information, is this the same thing or could I trouble you for that as well please? Scotch Bonnet had the double spreader tall rig. Many thanks, Andrew Scotch Bonnet 41/039

16 October 2012 - 15:36
#4
Join Date: 02 January 2008
Posts: 1547

Dear Andrew
Thank you for the information.
The mast section was elliptical 298 mm long and 140 mm wide, with 4.8 mm wall, weight 8.73 kg/m.
The boom was circular with 153 mm diameter and 3.2 mm wall. If you order a hydraulic vang it needs to be checked that the boom is strong enough.
With this information the rigging company can calculate the moments of inertia. It would be good to send them a sailplan if you have one.
Appended the righting moment curve.
Kind regards
Lars

18 October 2012 - 22:49
#5
Join Date: 01 January 2011
Posts: 36

Thanks Lars, I have sent details off to the riggers and now await their further questions or shortly their first quote. Do you or the forum have any advice on things such as choice of furler, preferred method of attaching / stowing spinnaker pole, choice of 1 x 19 or dyform wire, whether it is wise to reposition halyard winches or lead halyards back to the cockpit rather than copy the original design without thinking (my first reaction is I was happy enough with them on the mast), choice of vang? I think with in boom roller reefing option I prefer the simpler and maybe safer alternative of slab reefing which is also a lot cheaper although I have not used roller reefing much - am I missing something and is this a poor option?
I also sent the riggers the sailplan and noticed the backstay is shown as 9mm 1x19 with a breaking strain of 16,500 lbs - this BS for 9mm doesn't seem to correspond with the tables I have looked at, in fact 9mm isn't listed, did wire used to be stronger in the '70s? Kind regards, Andrew 41/039

19 October 2012 - 16:05
#6
Join Date: 02 January 2008
Posts: 1547

Andrew
Here a few comments
Pls note that Dyform wire has sharp edges which tend to eat sail stitching, and is unsuitable with a hydraulic backstay tensioner, as it unwinds under high tension.
The S&S sailplan uses US wire strengths which are nominally higher than European strengths, this is caused by different ways of defining the strength in the standards used.
If you intend to get a hydraulic backstay tensioner it is suggested the head- and backstay sizes are checked. The original sizes do not consider such effects, as tensioners appeared later. There may be reason to increase the headstay one size.
Kind regards
Lars

29 October 2012 - 22:23
#7
Join Date: 19 October 2012
Posts: 44

Dear Professor,
I am the owner of a 44 and we are approaching to refit the rigging .
Some of rigg specialist that we met have never told us that dyform wires are not suitable with hydraulic tensioner . Do you confirm and why?
We wish also keep the originals turnbuckles in Bronze but it might be safe to change them too? Inbox or bronze again?

What do you suggest about all?

Thanks a lot

Alberto
Pippus 44/011

30 October 2012 - 00:01
#8
Join Date: 01 March 2007
Posts: 147

May I ask the Forums advice on how to choose / specify / ask for quotes on a new rig for Scotch Bonnet? Some of the things I think I need to look out for are: mast needs to be tapered, it should be anodised, ideally made in 1 piece and not 2 pieces joined, need to think about reefing system, need to decide how and where to replace the halyard winches, need spinnaker pole, there were some features on the original rig like an internal line for running a replacement halyard but what other areas if I pay attention to detail should I specify up front? Do I need to worry about the type/thickness of the alloy or is it standard? Type of track? Separate track for the trysail or rely on gate as original. Then questions on vangs, furlers, etc. If anyone has experience with this type of project would very much appreciate any guidance and advice on best options when starting with a completely blank canvas! Thanks and regards, Andrew Scotch Bonnet 41/039

Hi Andrew, This may be out of the question for you, but why not have a look at a Carbon rig? I have just put one on Sarabande my 47, and whilst still very new, it is proving to have an incredible effect on sailing!

Rob Mably
Sarabande.

30 October 2012 - 06:31
#9
Join Date: 25 July 2012
Posts: 30

Dear Pippus,

Rod does not twist.  1 X 19 wire is laid with the inner 6 wires spiralling in one direction and the outer 12 wires in the opposite direction. Dyform wire is all twisted in the same direction hence the dyform can be untwisted unless BOTH ends are held.  The ram in the hydraulics can turn.

When the dyform is loaded up it untwists.  When the load comes off it doesn't always twist back up to its original form.  After several/many loadings the strands can get 'out of place' and never lay back into their original positions.  etc.  etc.  etc

David 43/12

30 October 2012 - 08:54
#10
Join Date: 02 January 2008
Posts: 1547

Dear Alberto
This information about Dyform can be found on Navtec's website, and David also kindly confirmed.
The bronze rigging screws can be used provided they are thoroughly inspected and found good. Rigging screws should have bronze in one part of the thread, as bronze is a slippery self-lubricating material. Stainless against stainless in threads is not a good choice, this combination increases the risk of seizing (galling) under load.
Kind regards
Lars

28 December 2012 - 00:51
#11
Join Date: 01 January 2011
Posts: 36

Merry Christmas and a happy New Year to all the S&S Swan Association.

Thank you for all the advice given, it has been very helpful in negotiating our way through this project, and a big thank you to the Professor for lots of specific advice off line which I'm sure wouldn't have been of general interest to the forum but has been invaluable for us.

A quick question now in case I lose your interest by the end - did our original masts have a masthead taper? I had been told for sure they would have but the more pictures I look at and the more I look at other boats in the marina I think perhaps we didn't and it is a more traditional look without a taper?

We are still finalising the specification so it may change but below is a summary of our likely way ahead, if anyone has any strong thoughts in any direction would love to hear them:

- The question of possibly replacing with carbon spars - I spoke to a few mast builders about this, one estimate was that the cost would be about double aluminium and another commented that we wouldn't really see a benefit on a Swan 41, so rather than study any further, aluminium it is.

- We will go with 1x19 rather than dyform but increase from 9mm to 10mm on fore and backstays - it was interesting how many riggers quoted dyform on the backstay with the hydraulic tensioner and didn't seem aware of potential problems.

- Probably a Harken mk IV furler

- A big decision has been to install new supplementary running backstays and an inner forestay

- Will stay with halyard winches on mast - Lewmar 1 x 40ST and 1 x 46ST

- We will install a separate track and halyard for the storm trysail rather than a gate into the main track and using the main halyard.

- Not to go with a boom bag because I'm not sure I like the look when sailing, although it would be practical

- Yes to lazy jacks though

- Still deciding on Norseman style or swaged fittings, all the riggers seem more than happy with swaged but a lot of non-rigger advice favours Norseman, I haven't seen anyone claim any negatives on Norseman apart from price so will get an alternative quote and see how much the difference is

- Stay with slab reefing, not single line, and note advice from Lars to discuss with sailmakers when we get to that stage in next few weeks to put in blocks at reefing points

- Track and batten car system - still deciding between Fredrickson type 22 and Harken Switch Track - similar prices but a lower stack height with the Harken compared with 100% positive reports on the Fredrickson

And once this is finalised on to the sails....

Happy New Year,

Andrew Scotch Bonnet 41/039

08 January 2013 - 13:47
#12
Join Date: 02 March 2007
Posts: 83

Dear Andrew,

I have a 41 (Trinket) and have had a surprising number of problems with the shrouds. The boat was entirely rerigged by the previous owner in 2007 using standard 1/19 and swaged terminals. For reasons we never fully understood, all the lowers (8mm) started failing halfway across the Atlantic. The outer ring of strands nearly all failed at the swages, this was on both the lower and upper swages. Seven out of eight swages failed. The inner ring in the wire remained intact.
The cap shrouds , forestay, and backstay were OK, but just recently I have found a broken strand on the top swage on one of the cap shrouds.
A rigger commented that 10mm for the masthead shrouds and 8mm for the lowers was a bit light considering the very heavy Nautor mast. However the most often made comment is that terminals ( Norseman type) are much kinder to the wire than swages. As these can be reused indefinitely, I would recommend them for a new rig.
Anyone else had shroud failures on 41s?

best regards

Cosmo Little

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