I'm planning on installing a Mark IV Unit 0 for our boat this winter. I was under the impression that it could be installed without removing the headstay, but after reviewing the installation guidelines it appears that it is possible only if you can access the head of the mast. I am looking at the foil which looks like it is locked in place at the head of the stay. Then all the foil sections are linked in place in a manner which suggests that either the mast has to be on the ground to lay it out, or you have to be able to use a lift to access the entire headstay while the mast is standing.
Then, I am looking at the toggle assembly which looks like it adds 2-5/8" to the overall length of the headstay (3/8" clevis pin). I replaced the headstay 5 seasons ago and it has had light use in fresh water so I'm unwilling to replace the headstay. I have a standard t-toggle assembly with a standard chainplate with a single tang. The instructions say that the headstay may require cutting and shortening (which I would like to avoid). They say something about alternatively replacing the lower turnbuckle t-stud with a stud/eye, but I fail to see how that changes anything unless you can eliminate the original toggle somehow (I'm not seeing how that is accomplished).
In any case, does the addition 2-5/8" affect rake very dramatically? Honestly, I haven't measured rake since I originally installed the new headstay. I think I set it for 6" rake. I assume that there may have been some stretch. I have about 2" total that I can take up in the turnbuckle with the thread of the studs.
Then, I am looking at the toggle assembly which looks like it adds 2-5/8" to the overall length of the headstay (3/8" clevis pin). I replaced the headstay 5 seasons ago and it has had light use in fresh water so I'm unwilling to replace the headstay. I have a standard t-toggle assembly with a standard chainplate with a single tang. The instructions say that the headstay may require cutting and shortening (which I would like to avoid). They say something about alternatively replacing the lower turnbuckle t-stud with a stud/eye, but I fail to see how that changes anything unless you can eliminate the original toggle somehow (I'm not seeing how that is accomplished).
In any case, does the addition 2-5/8" affect rake very dramatically? Honestly, I haven't measured rake since I originally installed the new headstay. I think I set it for 6" rake. I assume that there may have been some stretch. I have about 2" total that I can take up in the turnbuckle with the thread of the studs.