I’m about to order a Flat Head mainsail for my F21, but I’m having second thoughts though…
My F21 is a Shoal Draft with just 2’ of total draft of which only 1’ is keel. I’m concerned a flat head with the extra sail area near the head will cause too much heal and increase leeward drift. I guess, I’m asking if anyone has an opinion. Will it be a waste of money to go Flat Head vs. a more traditional Pin Head design?
Done correctly, the new sail should make the boat sail better–sail faster and point higher–than the original sail. This is because such a sail will have more forward force and less drag due to its improved shape. Therefore, there is less side force causing heel. This is mitigated by the fact that there is more sail area, but the tradeoff should be a benefit in your favor of improved performance.
Eric
Thanks Eric. Just waiting for my tax refund to come in before placing my order. The sail will be by Hyde using Dimension-Polyant 245 Square cloth. From all the reading I have done DP Square seems to be the best balanced weave Dacron on the market for radial construction. My new main will be a radial head with a cross-cut body similar (except for the head shape) to the sails Hyde makes for the J24s in the UK.
That’s an impressive 85% more than your E P triangle! Enjoy.
Jim D
Thanks Jim.
That is just a sketch I made, I’m still waiting for one from Hyde.
I’m shooting for a sail area of 210-215 sqft. That is only 5-8% larger than the original main for the F21.
I bit the bullet today and placed the order for my new Flat Head Mainsail. The sail will be made by Mack Sails in Stuart, FL using Challenge High Aspect 5.62 oz Dacron. The sail will be crosscut and, except for the fabric, essentially a twin of the one Moose had Doyle Sails make for him a couple of years ago. $1243 and 6 to 8 weeks is damn good for a USA made sail using USA made cloth, don’t you think?
I’ll get the sail in time to get some tuning in before the Brown’s Creek Sailing Association’s Great River Race, held the last weekend in September.
Oh, by the way… I’ll be dragging my boat down to Tampa Bay for the Fourth. If any other Freedoms are in the area I’d love to meet up for some fun on the water! 
Hey don’t forget to give updates on how the new main works!
Looking forward to hearing all about it.
I got a call from Travis at Mack Sails this afternoon. I am next in line for cutting and construction and my order should be ready to ship in less than two weeks.
The head is 4 feet and the final sail area works out to 218 sq.ft.
They sent me a scan of the sail design but, it is to faint to really show up so I added the blue background to make it more visible.
My new sail is ready to ship from the Mack Sails loft in Florida…
https://www.facebook.com/photo.php?fbid=10151597814417503&set=a.106635962502.96502.105435692502&type=1&relevant_count=1&ref=nf
looks beautiful, I bet you can’t wait to try it out.
happy sailing
Jim D
My new mainsail arrived from Mack Sails http://www.macksails.com yesterday and I decided to compare it to my 28 year-old original Haarstick. It was raining the morning so I drove over to church to use the parish hall floor…
The rain stopped so I drove the 40 minutes to Lake Guntersville to bend the sail onto the mast…
The wind was blowing about 8-10 knots so I headed out for an hour…
I’m not sure if it is just the 20 extra sq ft or the fact the sail is new and not stretched out; but the improvement was noticeable! 
Nice! did it heel any more than usual? I’ve also got a shoal draft and it always feels a little tender, but I wonder if the sail is just blown out.
-henri
My boat is also a shoal draft and no, I did not notice any more heal than with my old sail. In the 10 kt winds and stronger puffs, I did notice having to give a lot more lee helm (20 degrees) to keep the boat from rounding up to weather but maybe I just need to relearn my sail trimming for this new main.
Did I mention this sail is American made for the same price or less than the same sail from an overseas loft! Mack Sails is my new loft of choice.
I was having halyard problems today so I sailed with one reef tucked in on my new Mack Sails mainsail even though the wind was only blowing about 6 knots with occasional puffs to 9.
https://www.facebook.com/photo.php?v=10200973354799588
Here is a 35 second clip of me coming along side of a friend’s 32’ steel hulled gaff headed ketch for the ketch’s skipper’s point of view. 
I was reaching at about 3.5 knots and making 5.5 knots on a spinnaker run. Not to bad for only 6 knots of wind and one reef tucked in.