It roils, boils, tumbles and falls, races north, then south, and sometimes in both directions at once; yet at slack water Hell Gate at Roosevelt Island is as peaceful as a country pond. Sometimes, when you look at it, you think you are out to sea at Montauk Point, rather than on the banks of an inland waterway.

As rough as it is today, it is relatively benign compared to 150 years ago. A few cargo ships, ferries, and barges ply its waters without danger. It looks like a part of the sophisticated cityscape around it, just a little rougher. But 150 years ago, it was much different. New York was a port island, and much of its world traffic entered through Long Island Sound and the East River (which is actually a tidal channel), rather than, as it does today, through Lower New York Bay on its way to the ports of Bayonne, Elizabeth, and Newark.

Much of New York’s shipping came through the Sound since, in its natural state, the Sandy Hook entrance was more dangerous – with sandbars and reefs perfectly capable of ripping the bottom out of any ship. Long Island and Jersey shore sand is still routinely dredged out of these channels to keep them open. In 1781, George Washington decided to fight the climactic battle of the Revolution in Yorktown, Virginia. Although he wanted to liberate New York, which had been occupied by the British since 1776, he faced a daunting march south, and was encamped with the Continental and French armies in what is now central Westchester County. The difficulty in bringing the French fleet into the south harbor without up-to-date charts and experienced pilots was overwhelming.

The plan involved years of tunneling, below, from a shaft at Hallet’s Point (illustration on next page), with connecting radial tunnels, which would then be blown up to drop the river bottom.

A period description or a look at a map will quickly show the difference between the natural and manmade channels we possess today. Washington Irving, an early Nineteenth Century Manhattan writer and something of a history buff, now best known for Ichabod Crane and the Headless Horseman, described Hell Gate as follows:

Being at the best of times a very violent and impetuous current, it takes these impediments in mighty dudgeon; boiling in whirlpools; brawling and fretting in ripples; raging and roaring in rapids and breakers; and, in short, indulging in all kinds of wrong-headed paroxysms. At such times, woe to any unlucky vessel that ventures within its clutches. This termagant humor, however, prevails only at certain times of tide. At low water, for instance, it is as pacific a stream as you would wish to see. But as the tide rises it begins to fret; at halftide it roars with might and main, like a bull bellowing for more drink; but when the tide is full, it relapses into quiet, and for a time sleeps as soundly as an alderman after dinner. In fact, it may be compared to a quarrelsome toper, who is a peaceable fellow enough when he has no liquor at all, or when he has a skinful, but who, when halfseas over, plays the very devil.

This may sound cute, but the cold facts were that in the 1850s two percent of the ships traversing the Gate were wrecked or damaged, which amounted to one thousand running aground per year. Their decomposing corpses were clearly visible from the shore. As ships grew larger and heavier and subsequently drew more water (their keels reaching further down below the surface), the danger to them increased as they ran up against deeper submerged rocks.

The name says it all: Hell Gate, the gate to hell. In Dutch, “Hellegat” or “beautiful pass,” which may have been a play on words to escape ecclesiastical censorship and accurately describe the place, was a term originally applied to the entire East River at Manhattan. Transliterated into English, the term seems eminently appropriate.

A great collision takes place in the Gate between the waters of the Hudson River heading south, the Atlantic inflow racing north into the Hudson estuary and boomeranging back down the Harlem River, the waters of the East River itself racing north from the bay, and those coming from the Sound running west and south. This is aggravated and created by a four-hour delay in the tides between the Bay and Sound, generating the second-strongest tides in the world, by accompanying strong winds and the rocks in the channels.

A look at the U.S. Coastal Survey map of the area shows a very different Hell Gate from what exists today. Many rocks dot the channel, much of whose tearing surfaces were submerged like the proverbial 80% of an iceberg. Mill Rock is much smaller. The rocks necessitated the marking of three separate channels from the Sound and Harlem into the East River proper, designated the Main, Middle, and Eastern Ship Channels. And wind, current, and tide easily defeated anything man could contrive. Moreover, there was Hallet’s point, now rounded off and reduced. The site of a War of 1812 fort, the point was a grave for the many ships dashed against the shore and aground on a shallow reef by wind, tide, and rock.

By the mid-19th Century, the situation had attained crisis proportions, and the New York Harbor Commission requested federal assistance to open up Hell Gate to accommodate the constant increase in the tonnage and draft of ships seeking passage. But action began as a private undertaking. A local businessman hired a Frenchman, Benjamin Maillefert, in 1850, to begin blowing up obstructions after soliciting donations from merchants. Congress would not help. Maillefert proposed removing Pot Rock and Ways Reef for $15,000 by submerging canisters of gunpowder onto the rocks and setting them off from a safe distance. The first explosion blew four feet off Pot Rock, which served as an effective demonstration of the project’s efficacy. Some 284 charges provided 18 feet of clearance for Pot Rock, and another 240 lowered Frying Pan to 9½ feet and Ways Reef to 13 feet below mean low water. Then an accident disabled Maillefert and killed three assistants in 1852, putting an end to the effort. But it had been worth it: not only had the obstructions been lowered, but a dangerous whirlpool had been eliminated and the tide eased!

This demonstration also had a political effect: Congress appropriated $20,000, and this became the first major harbor job for the U.S. Army Corps of Engineers, which still performs these tasks. After the Civil War, efforts began in earnest with a study of the best way to remove the rest of the rocks and the Hallet’s Point reef in spite of a midwar suggestion that the channels be filled in.

A contract was awarded to an inventor who had come up with a floating rig designed to make demolition easy, but it ran afoul of uncontrolled river traffic and was ruined. Lt. Col. John Newton of the Corps’ New York district granted a contract to an inventor who had come up with a drilling machine on a barge to implant underwater charges in the rock but, by 1871, this boat suffered the same fate as the earlier one.

The obvious conclusion was that removing rocks and reefs would have to be done by underwater tunneling, which had been given a shot in the arm by the invention of trench warfare during the late War of the Slaveholders’ Rebellion.

General view of works at Hallet’s Point, showing offices, shops, stone removed from tunnels, etc.

This approach involved a complicated tunneling system under Hallet’s reef, where numerous radial and transverse tunnels were dug under the reef from Fort Stevens. It took seven years of tunneling, rock-breaking, and digging to create ten headings and connecting gallery arcs. Seven thousand holes were dug to receive 30,000 pounds of nitroglycerine, a high-powered charge, new at the time. On September 24, 1876, they were set off in a massive explosion whose force was mostly contained underground but produced a 123-foot plume. It then took another six years to remove the ninety thousand tons of debris produced by the blast.

Hallet’s Reef was no more, and the channel was upgraded. This tunneling method proved to be the key to future success.

Efforts then returned to the rocks in Hell Gate. The largest was Flood Rock. About 50 feet square, it was a major obstruction to navigation. A seawall was constructed around it, with a lift tower to remove debris from a shaft sunk 70 feet down. The work went on until four miles of tunnels were built and fifteen thousand holes for explosives dug.

Miners at work

From Mill Rock, the only one of the original islets that still exists, workmen tunneled to Flood Rock and the other obstructions, and planted 280,000 pounds of a hybrid explosive dubbed “Rack-a-Rock,” 5,000 pounds of dynamite in 50,000 charges. Of these, only 3,000 were wired for charges; the rest were to be set off sympathetically.

On October 10, 1885, General Newton’s daughter Mary pressed a key and set off the largest explosion the world was to see until the atomic age. Nine acres of water surface were lifted up into a 150-foot plume of rock and water witnessed by 50,000 spectators and a hundred cameras.

The diamond rock drill

“The work goes on day and night. The miners are divided into three shifts, each working eight hours a day, so that three days’ work is accomplished every twenty-four hours. About two hundred men are employed in all. Good wages are paid, and to ensure a fair day’s work from every man, miners using one-hand tools – holding the drill-bar in one hand and striking with the other – are expected to furnish five feet gauging at a shift, in average rock. For second-size tools, worked by two men on face or bench, seven feet are required; and an equal depth for third-size tools, worked by three men.” –Manufacturer and Builder

Although this blast exceeded by six times the next largest explosion ever set off, everything went off perfectly, with no casualties or collateral damage. The effect was startling – the channel was clear. No longer would there be three dangerous and narrow ship channels. Hell Gate was open! Port traffic increased to $4 million a year, and seers predicted that Ward’s, Randall’s, and Blackwell’s (now Roosevelt) Islands, all of the East River shore in Harlem, and the Queens shore – all then quite rural in character – would become bustling ports. This didn’t happen; the freight port remained at South Street and Brooklyn’s Red Hook, but later migrated to the lower Hudson as ship size further increased during the 20th Century.

Section of tunnel with two diamond drills in place

Divers drilling rock

The Corps went on to dredge Lower New York Bay and the Atlantic entrances off Sandy Hook to further open up the port from the south. New York then became an even more dominant entryway for the entire nation, a position it would maintain until the sinificant growth of Pacific trade after World War II and the invention of the container ship. These ships are massive (and growing larger), and require deep water ports – something New York has had trouble providing. The original ports on Newark Bay are becoming outmoded, and are being replaced by one on the Upper Bay at Bayonne. The Brooklyn shore, which has deep water, has become too densely built up to accommodate a large port that requires warehousing, parking, and factories.

Today’s relatively peaceful Hellgate is our remembrance of that heroic time when, working from below, miners, engineers, and explosives calmed the waters just north of Blackwell’s Island.

Island resident Robert Furman is a New York City historian. He is currently working on a book entitled Before Brownstones and After: A Preservationist History of Brooklyn. His e-mail address is bobfurman1@juno.com.