Hey Everyone! Does anyone have any information concerning mast rake settings, spreader rake, and rig (diamond wire and shroud) tension for the Inter 20? I am aware of the literature on the Cathouse website, but it is incomplete with regard to rake and tension. Thanks in advance.

I'm not sure these exist on paper. I would start with the Infusion mast settings as they are pretty close. We would run 41 on the loose gauge for distance racing but back down into the 36 range for course racing in light conditions. The mast is a tree trunk...

There is some pretty good info in this thread.

https://www.catsailor.com…3/inter-20-tuning-guides

--
Pete Knapp
Schodack landing,NY
Goodall Viper,AHPC Viper,Nacra I20
--

Thanks guys for the information. Sam, I have the bendy Southern Spars mast!

Hey trap,

The southern spars mast, which is what almost all the Inter 20's have, is a good rig, but bendy isn't exactly what I would call it! They are pretty stiff sections all around, and in my experience don't really respond to spreader rake or diamond wires like the post 2006 Aluminum Nacra sections.

Thanks Sam. I guess that means I cannot expect the mast to depower automatically in puffs as much as a more modern rig. With spreaders swept back and tension at 38 on Loos, it will bend and depower some automatically, but not as much. I can get a very nice bend in the mast using downhaul.

traphappy

I have the bendy Southern Spars mast!

I think the word most of us would use for that stick is, "tree trunk".

For some perspective, many (most?) of the Worrell teams bought shorter shrouds and longer forestays so that they could rake the mast WAY back. Also, because the mast was so stiff, it took a lot of diamond wire tension and spreader sweep. I remember helping load up a Euro team's charter boat at the end of the race and the diamonds felt like banjo strings; I think we found that he was north of 1,000 lbs.

For basic settings, what I remember was 1.5" of sweep and 450-ish on the wires. When we raked forward, the measurement was just behind the transom... In big air, the tension went up a turn or two and the rake went WAY aft.

Even though the mast is stiff, you need to make sure to protect it with rotation and cunningham when it's breezy. Also since it's stiff, you need to use the diamond wires to get prebend going, if you don't, you'll have to overload the luff of the main and still won't get enough bend.

Thank you! I set spreader sweep to about 1.5 inches and diamond wire tension to 35/450 lbs. Boat sailed great in light breeze. Really appreciate the help!