Fireside Classic: 1965 Mack Superpumper – Big Water From The Napier Deltic Diesel

In New York City, when major fires happen in the huge, tall buildings, fighting them is anything but easy.  Fighting the big fires in the Big Apple takes big water and that is where the ultimate fire engine comes in. In the 1960’s and 70’s, New York’s Superpumper ruled the mean streets and pushed the boundaries of truck-based firefighting.  Click through to read the story of the biggest fire engine Man has yet created.

In fire buff circles worldwide, this is quite a famous rig, though most current firefighters probably don’t know about it. It really is an amazing machine that folks with an interest in vehicles and machinery and no particular interest in firefighting should still find interesting.



If you’re going to have a big fire, you would do well to have it next to a large body of water in a big city because it would be accessible to fire boats. Fire boats, by their nature, are capable of putting vastly more water on a fire than a regular fire engine can. There is no reasonable weight or size limit to how large the engines and water pumps can be and they have an unlimited supply of water that they are floating in.

Firefighters would love to have a fire boat at every major fire, but of course that’s not possible since most fires happen far from water. What if you could have a fire truck with the capacity of a fire boat? That dream wasn’t possible technologically until the post WWII era, when NYC took up the challenge.



The single handline doesn’t look very effective!

The impetus came on April 20, 1963 when a Staten Island brush and lumber yard fire caused over $2 million of damage (in 1963 dollars). Numerous problems compounded each other to turn a bad fire into a complete catastrophe, with poor water supply chief among them. William Francis Gibbs, a naval architect who designed New York’s largest fire boat, had been thinking for years about a land-based super-sized pumper truck and was able to use this fire to convince the FDNY to let him design it and have Mack Trucks build it.


water relay with at least 3 fire engines


For those not familiar with fire operations, here’s a few baseline considerations that will help to explain the rationale for a Superpumper. Water supply at a fire is limited by the capacity of the water mains under the hydrants in the area. You can hook up to multiple hydrants, but if they are all on the same main it doesn’t actually increase the amount you can pump if you at the main’s limit. If you have a big fire and you’re lucky, you’re near a large feeder main and not a smaller distributor main. (in our city, hydrant heads are painted different colors corresponding to the size of the water main). If you’re really lucky, you’ll be near a large pond or lake or even a shoreline and you can draft water directly from there. You can get water from almost anywhere by setting up a relay with multiple pumpers, but that takes a lot of time to get enough engines there and set them all up. A single engine can’t just pump into an infinite length of hose because of hose friction loss (and gravity if going uphill). The pressure required to overcome that would burst the hoses close to the pumper, assuming it even had the capacity to pump that pressure (which a standard engine wouldn’t).

The motivation for the Superpumper is that it allowed firefighters to use a single unit to get very large quantities of water from the nearest suitable source within 2000 ft. (well-supplied hydrants or a large water body) and pump as much water as you could normally get from several individual fire engines. Also, with a very large capacity pump, water can be directed through an extra large water cannon to put huge quantities of water in one focused area.

Two important technologies had to be available in order to design this supersized pumper. One was hose that would withstand the high pressures.  The U.S. Navy had developed high pressure hose technology during WWII, which enabled hose to be made for the Superpumper which was light enough to be manageable and pressure tested to 1000 p.s.i. (4-5 times the pressure rating of regular modern fire hose).

The second thing needed was a motor that was powerful enough to work a very large pump but compact and light enough to be installed in a truck trailer. The answer to this need was a British engine: the Napier Deltic Diesel. A more exotic configuration for an engine would be hard to find.




The Deltic is a supercharged, two-stroke, opposed-piston engine with no valves. As used in the Superpumper, it has 18 cylinders, 36 pistons and three crankshafts. This engine was developed during WWII (again) for use in light, fast naval boats such as Patrol and Torpedo boats. Though designed for boats, it was also used for trains in the British Railways Class 55 and Class 23 locomotives built in the early 60’s. I’m not aware of it being used in any other fire service applications.


For those (like me) not familiar, a two-stroke Diesel design uses forced air induction and no valves (ED: some two stroke diesels, specifically the EMD/GM/DD two stroke family has exhaust poppet valves). The intake phase starts at bottom-dead-center (BDC). The mechanically driven blower charges the cylinder with air. In the early phase of intake, the air charge is also used to force out any remaining combustion gases from the preceding power stroke.

As the pistons approach each other, the intake charge of air is compressed. Near top dead center, fuel is injected, resulting in combustion due to the charge’s extremely high pressure and heat created by compression, which drives the pistons apart. As the pistons move downward in the cylinder, they will reach a point where the exhaust port is exposed to expel the high-pressure combustion gasses.The intake port containing pressurized air is also exposed, and the cycle starts again at BDC. (adapted from Wikipedia)

The engine was rated at 2400 h.p. @ 1800 r.p.m. I have not been able to find any references which list displacement or torque rating.



Above is the Napier Deltic engine as mounted in the Superpumper. It was placed behind glass-windowed folding doors, which was appropriate because it allowed the world to always be able to see the exotic engine. From the outside, it resembles a very large conventional V engine but looks can be deceiving. When running, it certainly couldn’t be mistaken for a regular engine because the exhaust note was a constant buzz and loud enough that firefighters working near it were required to wear ear protection.



This drawing of the gearing in the Deltic engine, and the images above, make it clear this is no conventional engine. The gear trains in the phasing gear casing transmit the drive from the three crankshafts to a single output shaft located through the center of the triangular housing. Though complex, none of the research I did said it is a troublesome powerplant at all. In fact, the only mention I saw of problems with the system were with the Mack tractors which were prone to breakdown. The department neglected to get reserve tractors, so if either the Pumper or Tender tractor were down for repair, the whole system was out of service.

The Superpumper was actually a three part system:


1. The Pumper itself, consisting of a tractor and semi-trailer. The tractor is a 1965 Mack F715FS with a Diesel V8 engine.  The engine has a Power Take Off for an air compressor used to start the trailer-mounted Deltic engine and the priming pump for the main water pump. It is also equipped with an ether injection system for cold weather starting. The trailer contained the pump engine, pump and twin 200 gallon fuel tanks. The Deltic engine is connected to a DeLaval six stage centrifugal water pump mounted at the rear of the trailer. The pump was made of stainless steel to allow for fresh or salt water. It is rated at 8,800 gpm and has a maximum pressure output of 700 psi (gpm goes down to 4,400 at maximum pressure). For comparison, a regular FDNY pumper at that time was rated at 750 or 1000 gpm. Most modern pumpers are rated 1500 or 2000 gpm with maximum pressure around 250 psi.


2. The Supertender, consisting of a tractor and semi-trailer. The tractor is the same model as the pumper’s but has a 10,000 gpm water canon (nicknamed Big Bertha) and hydraulically operated stabilizing outriggers. The trailer holds 2,000 ft of 4 1/2 inch high pressure hose, a pressure reducer (to attach low pressure hand lines) and compartments for equipment.

At a fire, the tractor can be quickly detached from the trailer and maneuvered more easily where needed to use the water cannon. The cannon could spray up to 600 ft, though typically did less. The water force could knock down walls, so it had to be used carefully!


3. Satellite Tenders. The system had three Satellite Tenders, each with a 4,000 gpm water cannon and carrying 2000 ft of 4 1/2 inch high pressure hose. The tenders were 1965 Macks with Diesel engines, very similar to FDNY’s regular fire engines at the time except they didn’t have a water pump.

The Tenders were housed at strategic locations around the city and would typically arrive at a large fire before the Superpumper and Supertender. The Satellites could set up ahead in a good location and be ready to use their deck gun when the Superpumper was set up, using hose off of or hooking up to the Supertender. Alternatively, they could go to wherever the Superpumper was located, hook up their hose to it and drive to where they were needed at the fire, playing their hose out behind them.  The strategy would be situational, of course, with the set up being much easier the closer the water supply and the Superpumper were to the fire.


Mack factory photo of brand new Satellite prior to delivery and decals


The Superpumper was in service from 1965 to 1982 and had a long record of success. At an early incident in 1965, it was used at an 11 (!) alarm Brooklyn lumberyard fire (not unlike the 1963 Staten Island fire that spurred its development) and drafted 7 million gallons of water, sparing the city’s drought-weakened fresh water supply. At a 1967 postal annex fire, it supplied water to the water cannon on the tender truck, its three satellite units, two tower ladder trucks, and a portable manifold with multiple hand lines all by itself.


Satellite 1 near the end of it’s service life


The Superpumper system has never been replicated in any other city, probably because of the huge initial investment. The price of $875,000 would be over $7 million today plus the dedicated manpower to staff it, a price that probably only the largest fire department in the country could justify for a single unit.

Though the system proved itself over the years and responded to over 2,200 incidents, FDNY elected to retire it apparently mainly for financial reasons. New York City was financially strapped in the late 70’s and early 80’s. The aging system needed to be replaced, but the department elected instead to replace it with six 2,000-gpm pumpers along with satellite hose wagons. They called it the Maxi Water System, but the fancy name couldn’t make up for losing the biggest, baddest fire engine the world has ever seen.


I’ve alternately used past and present tense when talking about the Superpumper because both the Pumper and the Tender do still exist, in private hands and not together from what I can tell. As a big fan of Then and Now books, I’ve included photos above of a Satellite truck brand new and after many years of use. Something about seeing how places or vehicles change over time fascinates me!

References include:

Fire Engines, Firefighters by Paul C. Ditzel, 1976. Older but good book on the history of firefighting in U.S.

New York City Fire Trucks by Wayne Sorenson and Donald F. Wood, 2002. Pictorial history of NYC apparatus, horse drawn to modern. B&W, but a really cool overview.

With New York Firemen magazine, 2nd quarter 1966 by John F. Romann. WNYF is a magazine written and edited by and for FDNY firefighters. I recently discovered this periodical when I found a stash of old issues at a fire station, which to someone like me is fascinating. This issue had an article on Diesels in the Fire Department, which were just coming into use in the fire service. It also contained a lot of info on their recently purchased Superpumper, including the Deltic illustrations above, which were better than any I found on the internet. This is where I got the idea to write this article, though of course I’ve been aware of the Superpumper for a long time.

Mechanical Engineering magazine, Nov 1965 by John Lehoczky, Jr. An article written by the director of Mack Trucks fire apparatus division at the time the Superpumper was built. I found it scanned on this Flickr page with a trove of photos.

BangshiftXL website, Feb 16, 2018 by Brian Lohnes. Good informative article that I found most of the internet’s best pictures in.