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Sail & Rigging - Tuning tall rig 38
12 August 2010 - 11:15
#1
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johncollins
Join Date: 02 January 2008
Posts: 21

Tuning tall rig 38
We are about to enter our local regatta which lasts for 5 days usually all wind conditions prevail,we have invested in a loos gage we also have an hydraulic back stay adjuster all we need now is a rule of thum gage to get the optimum speed.We of course realise that trial and error may be the way forward
We need all the help we can get as we find now our IRC no .950 leaves us rather uncompeditive with new racer cruisers in our rating band ,which have been specifically built round the irc rules.
We would be most pleased for hear from members
john collins
Satisfaction swan 38 1974
21 August 2010 - 13:08
#2
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the professor
Join Date: 02 January 2008
Posts: 1547

Dear John

Enclosed pls find target speeds for Swan 38 tall rig

Kind regards

Lars
21 August 2010 - 19:42
#3
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Jyrki
Join Date: 31 January 2007
Posts: 52

Dear Professor,
Does the target speed table for Swan 38 extra tall rig differ significantly from the tall rig table?
Regards, Jyrki
22 August 2010 - 10:30
#4
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the professor
Join Date: 02 January 2008
Posts: 1547

Jyrki

Enclosed the same table for the standard rig.

The extra tall rig can be expected do show roughly the same differences compared to the tall rig, as the tall rig shows compared to the standard rig.

Should I work out a new table for you?

Kind regards

Lars
30 August 2010 - 11:58
#5
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johncollins
Join Date: 02 January 2008
Posts: 21

Dear Professor, Does the target speed table for Swan 38 extra tall rig differ significantly from the tall rig table? Regards, Jyrki

Dear professor,
Thanks for the reply, we have just had our local regatta in which we did very well against hot racing boats like, A31 ,CORBY 25, SUNFAST 32 and J92. We were out of the prizes but were very pleased with our performance and we were well up with the pace.
We will have a good look at your tuning chart, but we have decided to invest in a new roller reefing rig along with a new racing furling no1 sail. At the moment we are leaning towards a Harken the main reason for this is as you might guess is to lower our IRC no.

Have you or any other members any advice as to sails which will give us the optimal performance? For example we are thinking of using a slightly smaller furling genoa than our current 150% Genoa which sweeps the deck and wondered what experience people had had with smaller overlap genoas.

Regards
John
31 August 2010 - 18:57
#6
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johncollins
Join Date: 02 January 2008
Posts: 21

Hello again Professor,

I have had a look at the data for the IOR rig in comparison to the tall rig and seen that there is little difference between the two setups. I had a chat with my sailmaker who told me that he has several customers with old swans who have upgraded their masts and also said that he knew of a Swan 38 with an IOR rig whose IRC rating was 0.916 which is substantially better than our current rating of 0.950 and would make the boat much more competitive!

I wonder if you know of any Swan 38 owners who have fitted a new mast and given that a modern mast would probably require 2 spreaders as opposed to the current single spreader set up, would we need to change the chainplates?

Thank you!
John

31 August 2010 - 19:21
#7
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the professor
Join Date: 02 January 2008
Posts: 1547

Dear John

Doing well compared with the other boats would suggest there was enough wind.

Many yachts use a 130% furling headsail as a good compromise giving easier handling with more or less the same performance. This will lower your rating slightly, and make the yacht more competitive when it blows, but in light weather she suffers somewhat.

Kind regards

Lars

 
01 September 2010 - 10:19
#8
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johncollins
Join Date: 02 January 2008
Posts: 21

Thank you for the reply,

We are considering making the change from a tall rig to the IOR rig. I am told by the mast manufacturer that this would require a two-spreader mast. We wondered if this could cause any complications with the existing chainplates and if any modfications would be required? Do you now of anyone who has done this?

Regards
John
01 September 2010 - 19:54
#9
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the professor
Join Date: 02 January 2008
Posts: 1547

John

Upgrading the mast to a two-spreader section might not be a good idea as this increases the IRC rating.

The goal of the rule makers is to make the rating correspond to the performance.

The boat with the low rating probably reduced rated sail area, this gives an advantage when it blows,

With two spreaders the load distribution in the shrouds changes, V1 sees more load and D1 less, and this causes changes in the shroud and rigging screw pin sizes.

Kind regards

Lars
28 August 2012 - 20:43
#10
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Lund
Join Date: 07 May 2008
Posts: 34

Dear professor,
Sorry if you have been asked this Q before: I have found that my Swan 38 (hull # 108 standard Tall Rig) goes faster on starboard tack than on port tack - I have a feeling that the rig has not been tuned correctly for optimum speed - I will be replacing the standing rigging this year - when we re step the mast what are the best procedures for adjusting the rigging in a methodical way for optimum speed. ie mast base/ spreaders / mast rake etc? Are there any ideas on what to replace the standing rigging (forestay/backstay) over the standard measurements?
Thanks,
Patrick

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