Author Topic: Marconi 12 1/2 sail plan  (Read 11550 times)

Erick Singleman

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Marconi 12 1/2 sail plan
« on: May 17, 2013, 03:00:50 PM »
There was a post back in 2009 that had a question about battens in sails.  I thought Id share some information I came across in gathering all of the details in preparation for ordering my new sails for my Marconi rigged 12

An interesting note on battens: I noted sail expert (dont recall the name) had a blog on the internet that I read a few weeks ago stating that battens only provide a value on sails that have a roach.  Now, there is no roach drawn on the mainsail of the 1938 Marconi sail plan, I don't presume there was any roach on the gaff plan either.  There are no battens drawn on the 1938 sail plan either.  However I have seen several Marconi rigged boats with what appear to be significant roach in the sail, and with battens installed, some even with jib battens.  I therefore wondered what the hell I was going to do for my sails.

Adam, a while back, was kind enough to let me borrow his Herreshoff catalog from 1935, and in this catalog it shows a sketch of a Marconi rigged 12 1/2 sailing.  The jib had no battens and the main had three battens.  The main also appeared to have a very slight roach to the sail.  The wish-boom rig in the same catalog also shows a very slight roach in the main.  In Joel White's sail plan for the Marconi rigged Haven there is also a very slight roach in the main. Okay slight roach wins.

With this information, I decided to go with very slight roach and three battens in the main and no battens in the jib because there should be no need for battens in a working  jib like this (well, according to some experts anyway, and my sail maker agrees)).

So why do I have so many photos of Marconi rigged 12s with a god deal of roach in the main?  My guess is that they may have had their sails made to the CCSB Bullseye sail plan.  Wendy Goodwin at CCSB tells me that the sail plan for the original Marconi rigged 12s is different than that of the Bullseye, and the center of effort is different. 
The wife says I can have a mistress as long as her ribs are made from white oak.

Charles Barclay

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Re: Marconi 12 1/2 sail plan
« Reply #1 on: May 19, 2013, 10:23:31 AM »

Nice post and good to see you making progress.  No ribbing about the ribs this time...

The short answer to your question is:  they had different sailmakers who made sails for different clients.  The long answer is:  go talk to the sailmaker. 

Before you go, be ready to answer or at least discuss the following:

1.  Prevailing wind conditions (direction and strength and number of reefs)
2.  Material you want (it's ok if you don't know, have him give you options).
3.  Level of performance you want.
4.  Durability and price. 
5.  Intended use: All purpose, race, cruise only?
6.  Is it class legal?

North Sails will make a spanking new aramid main for my Dad's catboat.  But why do it, it's not class legal, and he never sails in more than 22 knots because the club calls the races when the forecast is for more than 18. 

The 12 1/2 was not a strict one design as we think of them today with class measurer's and +/- tolerances you can't slide a credit card through.  There was variation, especially in sails, as can be seen with the S Class sails on page 155 in Maynard Bray and Carleton Pinheiro's Herreshoff of Bristol (storm sails are shown).   

In my children's junior sailing program, the "training" sails for the pram El Toro have hollow or no roach with no battens while the racing sails have maximum roach and three battens.  The difference is about 7-8 sf of sail area.  They are made that way for simplicity, ease of care and cost.  ...   Until this spring when the local college coach's 10 year old 60 lb daughter showed up with an intermediate sail with a smaller positive roach and battens.  She cleaned up in the class in the first regatta against 8-15 year olds. 

It was the right sail for the right day with the right person at the helm.  That's why you want to go talk to the sailmaker about what's right for you.  It's the engine for your boat. 

Just remember, Captain Nat invented full length battens for Clara.... ;)

Good luck.

Jon Brooks

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Re: Marconi 12 1/2 sail plan
« Reply #2 on: May 21, 2013, 06:22:20 PM »
I can only speak to the sail plan of "Minx" which is on the floor of the Museum.  She had a roach, three removable battens in pockets on the main, and I'm pretty sure two on the jib.  The sails were Ratsey & Lapthorne.

We also had a set of Egyptian Cotton sails stamped "Herreshoff", and to tell the truth, I can't remember if it had battens or not.  The sails should be somewhere around the museum I would think!

Jon  8)