Recently I went up the mast to check the rig after we found an unidentified nut and washer on the deck, and Robin posted a photo on the Outremer owner’s forum. In the photo, I had attached my climbing harness to the 2:1 halyard block that is normally connected to the head of the mainsail. Outremer saw the photo and posted back saying – Never use the main halyard to ascend the mast!
At first I was a bit surprised, but after a conversation with them, I realized that not only were they correct, I was damned lucky that nothing happened, as I was unknowingly attaching to the most dangerous line on the boat for mast ascending! Here’s why…
On a boat that has a 2:1 mainsail halyard, there is a fixed point where the halyard attaches to the top of the mast. This point can not be inspected from the deck. If it lets go, you will fall. Take a look at the drawing below:
The safe way to go up the mast, is to tie in to any 1:1 running line. The only fixed point should be the end that attaches to your harness. The other end will be on the winch. On our boat, this could be the topping lift or the running line on the mainsail halyard.
To tie into the running leg of the main halyard, use a Bowline on a bight knot.
Before tying in, you should pull the entire line through and inspect it completely, to make sure there is no wear, damage or chafe. It’s also a good idea to tie onto a second line as a backup. I usually use the spinnaker halyard as my backup safety line.
I fitted a snapshackle to the end of the topping lift so we can disconnect when needed to go up the mast. In the case when the mainsail is raised and I need to go up, the only line that will get me to the very top of the mast is the topping lift.