i550class.org

Chad, I'm thinking od using a rigging setup like you have, so the prebend loads go back to the mast,instead of down to the hull. With the heavier, thicker mast I have, it makes sense to keep these loads off the chainplates, so I don't end up deforming the hull shape. Can you send me a diagram of your standing rigging? Or give me an idea of how to set it up? Thanks

viewtopic.php?f=3&t=30&start=50#p1609

…is a link to most of my rig stuff, and a little description a few posts further down. I've added D1's since that drawing was made, but most of it is still relevant.

I wouldn't think of the topmast stays as "prebend" stays. They are just to control the mast tip, and in my case are set pretty soft. The I-point stays (over)set the prebend, and the D1's dial it in, and working together they provide headstay tension. You're going to get all the headstay tension you need with 300-400 pounds of main stay tension, and your D1's will be something like half-to-three-quarter of that. If you focus on getting the headstay tension you need, adjusting these two stays becomes a little more intuitive. That t-boat article in the thread linked above is good at explaining this.

To reduce boat bending forces, place your chainplates as close to the sheer as possible and swept back at around 30 degrees. Taking the topmast stay to the mast butt (diamond-style) reduces boat loading, but not by much- it's the lightest loaded stay. Reinforce your hull under f89 so the compression post doesn't go through the bottom- not a "duh" comment, good builders have been caught out by this. Make sure all the panels (bottom, hull sides, and deck) from the mast to the bow are stiff and don't buckle (use stringers), so that you don't lose headstay tension that way.

Lemme know if there is anything else I can share to make things more clear!

This is pretty good stuff. Is there anyone else out there that has suggestions? Remember, I'm using a mast off a catamaran, a lot stronger than the usual i550 mast!