Helios has a mast that tops out at 91 feet over the water. Climbing it can be a thrill.
I (Dale) was the first to climb it, done out at sea on the Bay of Biscay off the coast of France last August when our halyard got caught on a fixture near the top of the mast. Fortunately the ocean was relatively calm, but even the gentle swell made it a challenge. Our daughter Lindsey (the avid rock-climber in the family) climbed it during her winter break visit to the boat and showed that it can actually be climbed quite gracefully.
Dale atop the mast
Bay of Biscay video from the mast top
Lindsey harnessed-up and floated to the top like it was just another day at the climbing gym. There are multiple techniques one can use. Dale used a bosun's chair. Lindsey used a climbing harness. In both cases, we hoist the person on one of the halyards (mainsail halyard, the dedicated "man-lift" halyard, or the Code-O halyard) using the electric winch.
Lindsey preparing for her climb
There are lots of reasons to climb. In our case it was to release a tangled halyard and to check lines for chafing. It's also necessary for installing or fixing equipment on the mast top (e.g. radio antennas, radar, lights, wind instruments), or threading new halyards down the mast.
Lindsey checked that our trade wind sail halyard was in good shape
Lindsey at the top
Video of Lindsey's down-climb
Riggers who do such mast-top work as a profession all prefer climbing dockside with no waves and light winds. I can see why. At 90 feet up, just a 5-degree tilt of the boat from a wave is an 8-foot swing in one direction, followed by 8 feet in the other direction. It's very hard to hold on with that kind of movement. How the ocean racers do it in 30-foot seas is beyond me.
Helios from above