Overview
Want to free solo a natural arch--a delicate one--without being reviled by climbing community and general public? Want to have this arch all to yourself and yet reach it in only a few minutes from civilization? Then the Hammerhead is for you.
View from the NCAR road This satellite of the Fourth Flatiron offers a unique scramble along the 50-foot span of a well-hidden arch and up a summit block that looks a lot harder than Class 4. Great views from the slopes and the summit of the formations that line the sides of Bluebell Canyon--from the Third Flatiron and the Ironing Boards to the Fifth Flatiron and Royal Arch.
Royal Arch
The approach is less than a mile from the Bluebell Shelter, the climb is among the best at its grade, and the bushwhacking on the way down is, by Flatiron standards, short and mellow. All in all, an excellent way to spend half a day.
Getting There
The approach is from the Royal Arch Trail. From Chautauqua, follow the signs for Royal Arch to Sentinel Pass. Descend south of the pass for a short distance until, on your left, a trail branches toward Woods Quarry. Stay on the Royal Arch Trail and, from this fork, measure about 100 feet. Look sharp for a very faint climber's trail to your right. Spying through the trees, you should see the base of the Hammerhead some 50 feet ahead, and, if the angle is favorable, the overhanging summit block that gives its name to the structure.
Route Description
The route is comprised of two distinct sections.
Underneath the arch The first consists of two long pitches on the East Ridge of the Hammerhead. About half way up, the route goes along the arch mentioned in the overview. The climbing is mostly Class 3, with a couple of Class 4 moves: one at the very start, and one just above the arch.
The east ridge ends at a small summit, separated from the summit block by a notch. The summit block is intimidating, and the direct finish on its north face looks a very stiff 5.7. Fortunately, there is a much easier option on the west face.
View from the northwest corner Scramble down to the notch and then right to the northwest corner of the summit block. Here, you are off the structure, and, if you want, you can hike down. At the base of the west face is a jumble of boulders that provide access to a ledge that crosses the slightly overhanging west face. Gain the ledge and follow it in ascending traverse until you come to some excellent jugs that put you on the summit. This last part of the ascent is technically easy, in fact easier than the east ridge, but exposure is significant and a fall would be fatal.
They say you are supposed to yodel while pulling on the jugs, but I forgot about it, and still did OK.
Descent
Two options are available to descend from the summit block. The first is to downclimb the jug ladder and the ledge.
The Hammerhead from Royal Arch The second is to rappel from the northwest corner of the summit block. There is a large, stout horn there that can be slung. You may find slings already in place, but don't count on it: Bring about 20 feet of webbing with you. The rappel is free-hanging and can be easily done with a 30 m rope. If you plan to downclimb, make a mental note of where the jug ladder ends on the summit.
Once back to the northwest corner of the base of the summit block, head down staying to the north of the Hammerhead. Your objective is to reach the Royal Arch Trail from the north at Sentinel Pass. Therefore, after the first 100 feet or so, do not keep too close to the rock, so that you can go around Two Move Rock and the Sentinel Boulders on easy terrain.
Essential Gear
A short rope (30 m) is enough for the optional rappel. A 60 m strand or longer is recommended if you rope up. The usual disclaimer about Flatiron scrambles applies: The technical difficulties are low if you stay on course, but it's easy for the inexperienced to get off route and get stuck. The rock is mostly solid, but will sometimes flake if you apply pressure to it. A fall would likely have serious consequences. Therefore, while accomplished climbers would normally go unroped on Yodeling Moves, this is not a good beginner scramble. If you decide to bring a rope, a light rack will suffice.
External Links
Mountain Project's Hammerhead page.
Rossiter and Roach's guidebooks cover this route. Roach gives it the coveted "classic" label.