Chris Gallienne wrote:

Frank

I calculate the required CE ( using 9% of WL fwd of CLR ) to be 2' 9" aft of the mast - this is the position of the static CE of the sail, not the mast. That will probably place the mast  somewhat forward of your existing mast, depending upon your sailplan and dimensions.

Chris

Sorry to take so long to get back to you. I messed up my membership.

Anyhow, so I did get my CE almost correct then. The mistake I made was thinking I had calculated the mast position correct? I guess I got confused when the pdf was describing the CLR and the CE while showing the drawing with the CLR and the mast placement. Looks like I need to go back and re-read that.

Thanks for the help getting me back on track.

Frank

Hi all,

I have a free to me '63<?> Columbia 26 that I've been thinking about converting to a junk rig.

I only have an Imperial drafting scale so my measurements are in feet and inches, sorry about that.

Anyhow, I got the ship profiles from SailBoatData.com and enlarged them so that 3/8" to the foot seems to be right (gives me 26' 3" from bow to stern on that scale).

Arne's pdf show that the CLR is calculated based on the underwater profile with or without the rudder. I included the rudder and the boat has a DWL of 19'. I cut the image at the waterline and balanced it on the scale. The balance point is 11' 3" back from the bow end of the waterline. Using Arne's formula the the CE should be 0 - 15% of the waterline forward, I came up with 2.8' (19' waterline) forward. This puts the mast approx. 2' BEHIND the existing mast.

Any ideas where I might have messed up?

Thanks,

Frank