CD 36 Sail shape control

[Kailua Kid]

Question primarily for owners or crew on the CD 36s from a new convert to the design: From photos and videos it seems that many CD 36s and Robinhood 36s are sailing without boom vangs and most without quick-adjust backstay tensioners. If that is so, how do you avoid excessive headstay sag in heavy air (without setting up the backstay too tight for light air conditions) and how do you avoid excessive twist in the main when running off the wind without a vang? I understand these boats do not have bendy rigs, but even so, it seems odd that the backstay is not readily adjustable on the fly for optimal sail shape for both the headsail and the main, and even more odd that boom vangs are deemed unnecessary by some at least who own and sail these boats. What am I missing here? Any enlightenment appreciated.

[John Stone]

I don’t have a stock 36 so my perspective is a little different. Couple things though. I always sail with a vang. There is little control over the main without it. I can’t use a traditional vang to base of mast as I carry hard dinghy there. So, I run a combo vang preventer to the bulwarks and led back to coach roof. It’s always incorporated. Always.

My rig is taller snd more bendy than a stock rig-rite spar. I don’t have an adjustable back stay though. I do induce prebend. So it’s there. I set up my headstay fairly taut though. For light air sailing I use a big drifter where I can fly it free or just ease the halyard a bit.

Most folks have a furler and the head stay needs to be tight. My advice is to set up your boat for all around performance.

Stock rig rite spars are very stiff. They don’t really bend. Another consideration is the 36 like most CDs has a bow sprit. The head stay tension is countered exactly by bobstay tension. By changing backstay tension you are inducing a lack of equilibrium on the bowsprit. Definitely putting excess pressure on the bowsprit though I can say if it’s damaging or at risk. A CD is not a “race boat.” You sail it a little different. Keep in mind the legendary Dorade did not have an adjustable back stay either and was and is still very fast.

You might reach out to John Ring. He races his 36 Tiara and probably has some value thoughts for you to consider.

[Kailua Kid]

Thank you much. That makes sense. I have watched the Tiara videos on YouTube several times to try to understand how the rig is tuned and how sail shape (really nice suit of sails!) is controlled. Tiara of course uses a vang but seems to have no quick-adjust backstay mechanism. I suppose with a stiff mast and a bowsprit, headstay tension and leach tension on the main are just not really going to be adjustable on the fly. Does the CD 36 owner’s manual provide a spec for the backstay and headstay tension? By the way, is that a 9’ or an 8’ dingy you carry on deck?

[John Stone]

Thank you much. That makes sense. I have watched the Tiara videos on YouTube several times to try to understand how the rig is tuned and how sail shape (really nice suit of sails!) is controlled. Tiara of course uses a vang but seems to have no quick-adjust backstay mechanism. I suppose with a stiff mast and a bowsprit, headstay tension and leach tension on the main are just not really going to be adjustable on the fly. Does the CD 36 owner’s manual provide a spec for the backstay and headstay tension? By the way, is that a 9’ or an 8’ dingy you carry on deck?

Leach tension is primarily controlled with mainsheet and vang. It would take a very bendy mast with a number of different sail control to affect leach tension otherwise.

9’ Fatly knees. I have had her for 17 years. I have bridge deck mains’l sheeting via an Antal 6:1 and full width traveler. Picture below shows mainsheet arrangement.

http://www.farreachvoyages.net
http://www.farreachboyages.com

[Kailua Kid]

Very nice!

[Bill Goldsmith]

On my prior CD (a 27) which had boom end sheeting, I never felt the need for a vang because I could get 90% of the effect of a vang by adjusting the sheet. On my CD32, I added a vang because the mid-boom sheet had little effect on controlling sail twist.

As far a backstay adjusters, I added a rudimentary one to my CD32 when I replaced my rigging a few years ago. I can tell you that I never find myself adjusting it to accommodate differing conditions. It makes tuning a little easier and is helpful when time to unstep the mast, but it's just not a sailing adjustment I found myself needing to make. I think the standard 10-12% backstay tension on a CD rig ends up being a pretty good solution in most conditions (at least for me).

[Kailua Kid]

Makes sense. Thank you for the input.