Windcheck Magazine ran an article in April 2020 on a new methodology for retrieving an MOB.
In addition we have made a sketch of how it works.
a couple other comments:
one of the keys is to make sure the length of the retrieval line to the right length.
Rich suggests a bright colored (not grey) spectra line about 1/4″ (6mm) and run it from the attachment point of the lifesling run it thru the halyard and run the halyard up to about 5 ft from its max hoist and then back down to the lifeline with enough room to get the MOB over the lifeline when the whole system is under tension and the lifesling is up under their armpits. If you use the polypropylene line that comes with the lifesling then subtract another 5 feet for stretch and keep the line out of the sun. If the retrieval line is any longer than this, you won’t be able to get the MOB over the lifeline.