Mast toplock-fallavlastere till storseglet

[NED1417]

Hey all,
We (in the Netherlands) read about in the Medvind (2018?) something about a so called mastlock, in Swedish a fallavlastere till storseglet.
We want to know how it works because we saw two different devices, one who must be mount on top of the mast on the side of the mainsail and one that is probably mounted on the front side of the mast considering the drawing we saw. We heard that not many sailors in Sweden use this device but we are curious about that.
Anybody give us an explanation?
See pictures also
About the drawing, we want to know how the knob in the halyard can pass the sheaf
middle picture; is there someone who can explain how this works?

[johan swe-1870]

I can't quite explain how it works. But I think it's mounted inside the mast. Here's an example:


Picture is from here http://swe515.blogspot.com/2017/05/helg ... ering.html

[NED1417]

Thanks, I see that it is mounted inside the mast.
So the knob on the halyard must pass the sheave on top.
And what happens than.............
Any idea where to buy?

[maja]

Get in contact with Göran Ejdeling. He has mounted such a device (i.e."fallavlastare") . You will find his contact details in Medvind, page 2.

[NED1417]

Thanks, I will try to contact him.