After a research on the web I finally understood what Lars meant with the phrase "blocks in the sail at the reefing points...". I understood also that the way to do the job is to have captive two-ringed tapes sewn in all the sail reefing cringles and I realized that such a setup could be very handy in all cases, even with traditional reefing. I probably reinvented the wheel but I plan to ask my sailmaker to do it this winter.

My question regards the expected loads. What is a safe dimensioning of the two-ring tapes, of the blocks and of the reef line for a 33 m^2 main?

Daniel, 411/004

Hi Daniel,
I don't know anything about the strength. However, what I realized today (while sailing with a reef) is that the distance between the reef point and the next luff slide car is important. I noticed that my tape-and-ring (only on one side of the sail, by the way) is more than half the distance from the next lower car to the one above. That way, a lot of sail luff is loose enough to allow the ring to be hooked on the ram's head, with the sail than overlapping the stacked cars. I figure that if the reef eye is too close to the lower car, the car stack will be in the way.
Best, Martin

Dear Philippe
I believe your present boom has sheaves for reefing lines at the aft end, what you need to add is a pair of sheaves at the forward end enabling the reefing lines to be led upwards, and two small lead eyes on the mast - not a major operation.
The reefing lines are led as follows - through the lead eye up to the luff reefing point, down to the new sheave, aft to the existing sheave, up to the leech reefing point, down to the boom, and tied around it, with a cringle in the foot of the sail determining the position.
The sailmaker to put in the foot cringle in the correct position, and blocks in the sail at the reefing points as this will reduce friction in the system.

Selden uses a different arrangement with a tackle inside the boom. You asked about the righting moment, and I believe they use the figure at 30 degrees heeling angle, for the 47 this is 9000 kgm.
Best regards
Lars

Dear Lars,
I wonder on these two issues: 1) is not there too much friction with a single line reefing, considering the sail area; would there be a substancial reduction of effort utilizing on the sail small blocks rather than the existing cringles? 2) how do you bring back to the small cockpit of the 47' the halyard and the two single reefing lines? Probably I might utilize one of the aluminum sheaves used for the genoa sheets, but in this case these lines would run on the deck. And I would need stoppers, as well. Alternatively I might run these lines on the coamings of the cockpit, but I feel I would need organizers and some extra winch...
Does anyone have on a 47 already have single line reefing and main halyard brought to the cockpit? This experience would be very useful, thank you

Dear Matteo
1. Using blocks at the reefing points reduces friction very much, and is strongly recommended. Looking at the loads involved the single line reefing arrangement uses four parts to pull down the sail against the halyard load with one part, and the load in the reefing line is clearly much smaller than in the halyard.
2. Suggest leading the lines from the mast along the coaming to stoppers in front of the secondary winches. These winches are usually free on the wind, if the runners are used they can be led to the winches at the main entrance
Kind regards
Lars

Dear Lars, thank you for your reply. Regarding point 1) I will contact the sailmaker for the installation of blocks. With regards to point 2)I hope to have understood correctly that you are referring to the winches close to the main entrance to the saloon (my original are Lewmar 48). This would mean anyway leaving the cockpit and getting to the bridge deck.In the alternative case of using the 55's in the cockpit, then the leads should go outside or inside the base of the 65 on the coamings of the bridge deck, and this seems to me complicate. At the end I think I will stay with the main halyard at the winch on the mast base. Thank you very much, Matteo (grampus 47)

Dear Matteo
Thank you for the information. I referred to the standard Swan 47 winch arrangement shown among the drawings on this website, there the secondaries are at the forward edge of the cockpit. It appears you have a different arrangement. You are right that the primaries are complicating matters
Kind regards
Lars

Dear All and especially the Professor,

This is a very interesting discussion which I have been closely following.  On my 43, I have the original boom which is not in great shape and so I am also considering a replacement boom.

Currently, the traveler is located in the cockpit and I find that the mainsheet winch is awkward to use.  If I understand the original logic, the placement of the traveler was a function of the "roller furler boom."  Is it acceptable to move the traveler to a position before the dodger and place the mainsheet winch in a horizontal plane below the dodger?  The Tartan 41, also a Sparkman and Stephens design, used this setup successfully.  If so, I would think that the boom would need three bales, each with a turning block, to disperse the load.

I am also looking to improve the reefing setup on my boat and I really like the idea the Professor recommended of adding turning blocks to the mainsail to reduce friction.

Thank you all for a very informative thread.

Chris Mabel's Casse Tete 43/003

Chris
With a slab reefing boom you can attach the sheet to the boom in any convenient position, but it is not advisable to go further forward than about half the boom length. It should be noted that in this position the sheet loads are doubled, and usually the boom then tends to bend, and the coachroof to flex. It is suggested that the strength of these two components be checked, and appropriate sheet blocks chosen
Kind regards
Lars

Dear Professor,

Thank you for your infomred reply. 

This winter, my plans include the deck removal and repair - either non-skid or teak - which leads me to painting and repairing the cockpit.  So, with this in mind, I may change the location of the traveler as described.  I would prefer to put this off for another year, and may do so, but that would mean repainting; etc.  so, we will see.

Thank you, again.  BTW, I like Garhauer bocks; etc.  Do you have an opinion?

Chris 

Chris
There have been favourable comments about Garhauer on this website.
Some idea of the load is needed in order to pick a SWL, and the line size considered.
Kind regards
Lars

Dear Professor,

Thank you. 

Yes, before I were to make any changes to the current setup, I would contact you abou the calculations. 

Ironically, the rigger with whom I spoke today did not like Garhauer hardware!  Do you have a preferred manufacturer of hardware?

Have a great weekend.

Chris 

Chris
Would your rigger accept Harken?
Lars

Dear Lars,

Harken is actually his preferred hardware provider.  My experience with harken has been poor, but possibly I had the wrong style?  And I did do some heavy sailing on my last boat.  Having said that, All of my Schaefer gear held up to every condition while the Harken did not.

The rigger says that he only recommends certain Harken equipment so that may be the difference between my experience and good experience.

The fact that you recommend it carries a lot more weight with me than the rigger - the company he works for has a good reputation but I do not know him personally and have just entered discussions with him - as a result of this thread!

Whichever route I choose, I would prefer to use one hardware company for all of the gear.

This particular rigger also recommended Selden - certainly I know of their masts and booms but was unaware of their hardware business.

Thank you.

Chris

Chris
Sounds like you used too small Harken gear if there were problems. If you prefer one supplier they have a big selection.
You are right that Selden deck hardware is a rather new thing, so far with limited choices.
Lars

Dear Phillipe,

I also have a 47CB (68) and would very much like to install electric winches where currently I have Lewmar 55ST's. Did you my any chance take any photographs from below to show how you achieved this? Would it be easier to install 55 EST? I would very much appreciate being able to contact you. My email is: melboudrot@gmail.com.

Mel, Cygnus Swan47CB (#68)

Dear Phillipe, I also have a 47CB (68) and would very much like to install electric winches where currently I have Lewmar 55ST's. Did you my any chance take any photographs from below to show how you achieved this? Would it be easier to install 55 EST? I would very much appreciate being able to contact you. My email is: melboudrot@gmail.com. Mel, Cygnus Swan47CB (#68)

Dear Mel
I have posted a description and 9 pics of my installation to you private email address. The new Lewmar Evo est 65 fits very well. You simply need to be creative down bellow with some neat surgical cuts. Then a cover box make it all look nice.

Cheers
Philippe
Farouche 47/050