McRig Sailmaking and Tuning

Rcsailing.net Technology Discussions
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Searching, I found a good amount of discussion on making conventional sails (sail blocks, draft, broad seaming, etc…), but did not find any specific threads on McRigs/Una Rigs etc… So hopefully, we can get some of the seasoned sailors to contribute their knowledge to this thread. With the growth in McRig usage and the ease with which a new sailor can sail it, this should be helpful to a lot of skippers.

I have started sailing my Brett B-2 and the plans came with two rigs. I am thinking I would like to try one of my own creations and would like some rule of thumb (some calculations OK) ideas to follow. I can calculate the geometric center of most any sail shape, but where should this be located relative the pivot point of the rig vs clr of the hull. The 2 sail plans with Brett’s boat seem very well balanced and it is amazing how the boat seems to sail itself to windward in breezy conditions.

Are they any benefits to making a sail with a panel or two?

My A-Rig does fall off toward the top, even in lighter conditions. How much is acceptable and how much can it be adjusted out. I have a sliding block to set pull angle for the clew and a separate sliding block along the boom to set the tension. I also created an adjustable tensioning device to control the luff.

Looking forward to seeing some good contributions.

Thanks in advance for your help.

Best Regards, Frank

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The 2 sail plans with Brett’s boat seem very well balanced and it is amazing how the boat seems to sail itself to windward in breezy conditions

Hi Frank,

Have you got any pics you can post?? I would like to see other B2’s in action.

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Hi Brett

Will do, but I need to finish a few things first. The deck has a round hatch cover, but the rest of the deck is simply covered with blue painters masking tape so it can be sailed before it is “monocoated”. Paint is still a sandable sealer primer. As stated, it a modified B2, so you may not recognize it. Also needs a sail # & graphics. B-Rig still not finished, but getting close.

It is amazing how dry it is sailing with the temporary deck and rough seas of our 1000 acre/250 hectar lake. So far, only the equivalent of a few drops of water one time. Oh, her name is: “Half @$$”.

I would also like to see some photos of one of your B2’s showing details of internal construction, keel support, servo placement, rudder linkage, mainsheet routing, etc. The sloped transom makes it tricky doing the linkage. How many other B2 's are out there?

Will post photos after I get IC time submitted.

Frank