Getting to the Top

One DIYers mast-climbing system.


As Practical Sailor’s testers found out during its test of bosun chairs, there are times when getting to the top of a mast is a far easier solo proposition than hunting for help. The first time I saw a middle-aged man go it alone, he hoisted a 3:1 block and tackle, rigged with 5/8-inch line, up a jib halyard. At the bottom end of the rig, he attached a bosuns chair. He simply pulled on the haul line, hand over hand, to the elevation he needed, then doubled the haul line through a convenient part of the chair and tied it off. With the 3:1 purchase, he was muscling one-third of his weight.

The block-and-tackle method worked, but there seemed to be a high-risk period of supporting ones weight aloft with one hand while doubling the haul line through the chair and tying it off. And what if you aren’t in good physical shape? What if the tail begins to slip through ones grip? It would be a very fast ride down.

We recently came across another homegrown rig that we think is better, and is easy for a DIYer to set up. Sailor Bob Callaway and his rigger, Craig Shaw, from Portland, Ore., developed a safer block-and-tackle, solo mast-ascending device from Callaway’s personal experience and near falls. It has a 4:1 purchase, which reduces the hoisting effort by 75 percent. The block and tackle is rigged with a 7/16-inch diameter, Samson XLS Extra T low-stretch line. The upper, stationary block is a welded Garhauer stainless-steel block. The original upper block was made of plastic and began to fail when it became side loaded while working aloft. The nice thing about the Garhauer block is that you can tie a safety line through the block sheaves and to the lifting halyard such that even if the block or the halyard shackle did fail, you have both sheaves tied to the halyard, Callaway explained. The Garhauer (30UAG/30UAB), rated as the Budget Buy in our recent test of 4:1 tackle would be adequate for the task.

Before considering this approach to mast-climbing, you should read this update, which offers a more detailed description of the equipment used for solo climbing and other important safety recommendations from climbers and the makers of climbing equipment. One concern is that some halyard materials are not well-suited for self-arresting brakes used by climbers.

Also be sure to read the sidebar article “Mast Climbing Tech Tips” which discusses general mast-climbing safety and offers some excellent tips from professional rigger Brion Toss.

Garhauer block
Here, you see the haul line on the right and the safety brake halyard on the left. The Garhauer block is at the top of the system, out of the picture, and is attached to the halyard.

When hoisting up, the user hauls on the large D-handle of the ascender clamp with one hand as well as the hauling the line with the other hand. On the moving block, which attaches to the bosuns chair, a one-way ratchet sheave is used. This adds a tremendous amount of one-way friction to the system and allows you to very easily support your weight with one hand while sliding the ascender up the haul line, said Callaway. Friction from descending creates a hotspot on the ratchet block sheave, so users should be sure to rotate the hotspot and spread the heat around the sheave.

Since that ascender is tied to the bosuns chair with a short lanyard, then even if you let go with both hands, you drop only a few inches before everything is snug again. As an additional precaution, a second halyard is secured at the deck and stretched tight to be used as a safety brake. A short line from the bosuns chair is fastened to the top of an ascender clamp to ride up the safety brake line. That way, when going up, the safety ascender just follows you up and usually does not require any interaction from you, Callaway said. When ready to descend, move the safety line to the bottom of the safety ascender so that it is easier to slide down the safety brake line. If everything else fails, this backup brake averts a disaster.

Testers liked Callaway’s 4:1 mast-ascending system. It’s effective, affordable, and easy to replicate. With a little effort and the proper gear, a sailor can safely go solo to the top and get his work done before any help has the chance to show up.

Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him by email at