Boomless Catamaran Rig Telltale Question

[OldCat]

I have a NACRA 5.8 - and noted some odd telltale behavior on the main last weekend.To review the boat's sail controls:No boom, so no boom vang. The boat has a traveller. Full batten main.Main halyard does not tension the luff, luff tension is by 6:1 Cunningham.The mast rotates & can be 'set' via lines,The mainsheet attaches like a genoa sheet, and the sheet angle can be varied by attaching it to a different hole in the clew plate. The effect is like changing position along a headsail track.Telltale windows are a bit above halfway up the main and near the top - standard position as installed by the sailmaker for these boats. I added a set further down, 1/3 of the way up - mostly as they are easier to see for when I need a quick look.The problem: I was often able to keep all leeward, and upper and lower windward tales streaming - but had trouble with the middle inside (windward) telltale - couldn't get it to flow. These are all mid-sail (fore and aft), not leech telltales.I think the mast is less disruption to flow than a typical monohull mast as it is elliptical and rotates - hence the sailmaker putting the upper two sets of telltales in a position more similar to a genny, but further from the luff.Ideas? Play with mast rotation - or Cunnigham? I think the mast should rotate to point to apparent wind - but am not really sure. OTH: that middle telltale is the closest one to the mast - so maybe even with the elliptical and rotated mast it is just getting turbulence off the mast?

 

[Joe]

Adjust your battens

Don't get a lot of beach cat stuff on this forum, but I like it. Years ago there was a very active NACRA sailors bulletin board that I followed faithfully. When the sponsor pulled the plug I was devastated. It was indicative of the drop in interest in catamaran sailing over the years. FYI it is still very popular in Europe. The new higher performance cats have awakened an interest in the US. However, they don't attract the novice sailor because the tech and physical skills needed to sail them are substantial. Regarding your questions; My first thought was that you may want to tweak the battens to set the draft depth at each section. To build some twist into the sail. I put the quick adjuster batten caps on my 5.2 and found it quite helpful. Adjusments are quite easily made on the beach by just tipping the boat on its side. Another concern may be that you are over-rotating the mast. I never went past 45 degrees.For what it's worth I rarely worried about the windward telltale on the main. I was only concerned with the leech and leeward telltales, although the windward was almost always flowing (maybe yours is top close to the luff). The leeward telltale helped me adjust the jib, whose main function is to control air flow through the slot and help turn the boat thru a tack. If my leeward and leech tales were flowing I was on it. My final comment is to grab a copy of Rick White's "Catamaran Racing for the 90's", if you haven't already.

 

[OldCat]

Thanks for the Book Recomendation

Joe: That book will really help - I have not sailed the cat the last few years - just got it back together. I need a 'refresher' course on catamaran specific stuff. Thanks.I think I will keep the telltales - mostly they work for me.I am worried that I have the battens in with too much tension - but am not sure how I would tell.