Sparcraft Masthead Tour, ATN Mastclimber review

“Dude, that Alex Honnold guy climbed up the face of El Capitan with no ropes and no help. You just have to haul your behind 40 feet in the air with a couple of ropes.”

After a certain amount of preparation, I made my first trip up the mast today. I haven’t found any other pictures of mastheads on the site, so I thought I would share some of mine. According to my casual research, my mast was made by Isomat US, Inc., of which a subsidiary was Spar-Craft. Here is an article from 1988 lauding Isomat’s ability to manufacture masts in quantity. I believe the extrusion form of my mast is a Sparcraft FM-230. Check it out at Rig Rite.

Aft section, backstay and topping lift cables shown. VHF radio cable and whip antenna, anchor light. Single sheave aft for the main sail halyard.


Somehow I had expected the head portion to be a separate cast element like the ends of my boom. Obviously it is all one piece, and a piece that has likely not been given any cosmetic attention since coming into the world.

Aft section, viewed from underneath:

Fore front/side view of masthead:
Forestay cable at center, three sheaves, center occupied by jib halyard, side sheaves empty except for tracer lines


Fore view of the masthead, from underneath:


So, I think I have two tracers running from my masthead down my mast. I know where one of the lines comes out, and that will facilitate sending up my new whisker pole topping lift. I hope I can find the end of the other tracer and replace it with new line. The present tracers have been weakened by age and weather.

ATN Mastclimber Review

After my initial 4-feet-off-the-deck test of the ATN Mastclimber, I was very pleased. Today’s trip all the way up the mast was a more mixed experience.

Here is my initial rig, with my climbed rope and the attached Mastclimber and my secondary line, which was my jib halyard, to which I was attached with an independent prusik knot:


The picture shows a barrel knot I originally intended to use, but it did not hold well. I consulted some interweb sources and used this knot instead:

ATN Mastclimber drawbacks:

-The ratchets are designed to grip rope and not fail. That’s great. But they aren’t designed to be grabbed by a hand and slid up or down. There is no concession (as far as I can tell) to actually using the ratchets to slide up and down. There should be some handles, softening of edges, etc.
-The ratchets and metal gear scratch the devil out of the mast. Perhaps due to my inexperience, once I got up over the second set of spreaders, I began to clutch the mast in an act which, if carried out by pre-adults, would be described as ‘dry-humping.’ I mean, it’s a little scary being that high up, and the mast is the only thing to hold on to. But the machined edges of the Mastclimber ratchets do a good job of banging up against the mast.
-It really helps to climb a taut line, but I wasn’t able to get the climbing line tight enough, as it sagged once I put my weight on it. The sloppy slack line below the climber makes climbing down especially cumbersome when one is trying to reach down and slide the foot cam down.

Other notes:
-The mastclimber comes with a toolbag one can clip to the bosun’s chair. The bag can be zipped. Zip the bag, even if you are only bringing up an iPhone (or else you might dump out your phone, as I almost did, passing down past a spreader).
-A good prusik knot feels just as safe as the mast climber cams and is easier to manipulate. I was able to descend with the prusik and feel like I could control/belay my descent with my thumb alone with considerable control. This downward slide was much easier to effect than sliding the Mastclimber cams back down the loose climbing rope.


Maybe the Mastclimber is not the right approach for me. If I had a standard bosun’s chair and three prusik knots with two lines, I wouldn’t scrape up my mast and I could ascend and descend faster, I think.

I’ll make at least one more trip up the mast in the near future to grab the tracers and pull through my new boom topping lift line, once it arrives from Defender (backordered).

Finally, here is a view of Richardson Bay, from Sausalito on July 3rd, 2020, from @ 44′ up: