With the assistance of my crew,? I replaced the Harken MK 1 Unit 1 furling system with a Harken MK IV Unit 1 furling system: the 32 year old MK 1 had gotten very difficult to furl! The new furling system took about 8 hours to install (having never done this before). The previous headstay was too short due to the MK 1 units proprietary toggle and stay tensioning system; so a new stay was required! With current availability of STA-LOK replacement parts , I chose to have the swages mechanically fastened with a swaging machine.?
The Harken MK IV Unit 1 furling system instructions were followed and their method of calculating and verifying the number of foils required and cutting of the top foil were spot on. I used the?Eye/Jaw Toggle Reversible 7411.20 with 1/2 inch pin to connect the drum to the stem. Did not need a link plate! I did end up moving the furling line to the PORT SIDE for better lead angle for the furling line; as my new ROCNA anchor would have possibly caused some line chaff.
The new Harken MK IV Unit 1 furling system has independent swivels for tack and head of the sail. This has the advantage of creating a very tight furl/reef of the headsail.
Daryl Clark