Eagle Boats (1918)

US Navy ww2USA (1918) 60 ASW vessels PE1-60.

Ancestors of WW2 PC Boats: The Eagle Boats

The ‘Eagle boats’ resulted from a request to Henry Ford by the US government, to apply his techniques to deliver in record time a very large serie of steel-hulled medium range ASW patrol boats before the end of the war. Eagle Boats were also tailored for the USN to fill a gap between destroyers and the common sub-chaser of the time: The mass produced wooden-built 1917 ‘110 feets’ boats. Steel-built in record time as the production facilities, tools and methods were setup, 60 were built, but not completed (but one) until Germany signed an armistice, they never had the time to prove their value, most of them being scrapped before WW2.

Operational context


The US entered the fray in part due to the sinking of the Lusitania in 1915. The American public grew weary of a supposed German ‘fifth column’, knew about an ammunition depot that blew up in NYC, about Belgian atrocities, or about the secret message to the financial support of a war by Mexico on the US (The Zimmermann Telegram). As it was related to submarine warfare and the new “barbarian” weapon that was the submersible, president Wilson before a joint session of the congress On April 2, 1917, so it took two more years for the prejudice to mature. However it would take at least six month to be on war footing, sent troops in Europe, or mobilize naval forces. A massive naval plan was adopted, but it focused mainly on destroyers and light cruisers as new battleships, not small boats.

At that time the unrestricted sub warfare targeted freighters and tankers without warning and met great success initially in 1915, stopped by the Kaiser with the sinking of the Lusitania, then resume again from February 1917, although this decision soon unleashed USN ships in the Atlantic, at the same time the British setup plans for a massive shipbuilding programme, both for ASW dedicated vessels and replacement by mass-produced trade ships for standard types. Another interesting development of the time was the quick development and generalization of naval camouflage.

U-Boat campaign 1915 area of operations
U-Boat campaign 1915 area of operations

USN response

Initially, there was no contingency plan for ASW warfare. Destroyer construction on a very large scale was already in full swing and due to their range and speed they were considered deadly for submarines, although their gun-only armament limited their effectiveness. The rapid development of air patrols was one such solution: The Aeromarine and Standard H4H floatplane series for coastal areas, mass-built Curtiss HS seaplanes for longer range while the British produced the Felixtowe series.

But the admiralty was slow to devise the construction of smaller ships, with the exception of a single model to be built in emergency right after the US entered war: Early in 1917 it was planned to cheaply mass-built ASW vessels with no strategic materials: These became the wooden Sc 110 ft series. SC stands for “Submarine Chaser” and 110 feets for their overall lenght, 33.5 meters long. With 4.5 m wide and a 1.70 m draft they were relatively nimble but could undertake long coastal patrols in moderately rough seas. They relied on aircraft engines, three Standard petrol ones, which together produced 600 bhp for 18 knots.

This was sufficient to catch a surfaced submarine, and more than sufficient to trail a submerged one for hours. The only limitation was the range, 1000 nm, at 2 knots. Elco was responsible for their production, chosen for their experience in mass-producing 80 feets launches for the Royal Navy. Wood allowed them to be built in very large numbers and short time and when signing the contract the US government hoped to have 345 boats ready for the 1st January 1918. They also planned to sent them to France, with two orders of 50. Despite the schedule was never met, the SC boats were considered a triumph of war mobilization, as in all 441 were delivered (out of 448 planned) until November 1918.

They were designed by Loring Swasey which would also design WW2 sub chasers as well. They were armed with a standard 3-in gun, 2 machine guns, and a Y-gun, but were criticized by the admiralty for their short range and small size hampered their service in the North Atlantic and North sea when deployed from European ports while the General Board warned when they were designed of the same issues. This criticisms were heard by the government that searched for a new, much larger and steel-hulled design, which turned to be the Eagle Boats.

Development of the Eagle Boats

drawing of the Eagle boat
The genesis of the Eagle Boats was very much the result of the previsible disappointment with the SC 110 feets boat. Although their manageable size and wooden construction allowed them to be cheap and quickly delivered from anywhere, the Admiralty wanted a long range, sturdier and seaworthy vessel that can patrol the entire Atlantic if possible, more in line with British ships such as their “Flower” series.

For their their construction, it was necessary to eliminate shipbuilders already engaged in delivering destroyers, larger warships, as well as merchant shipping. This time, the Bureau of Construction and Repair was put in charge of the design, and made one which was sufficiently simplified to allow a very quick construction by little experienced shipyards, also with modularity to allow spread delivery and final assembly possible. Tailorization as a construction method was already envisioned and there was immediately a name that came to mind of the government: Henry Ford.

Construction by Ford (short video archive)

Ford’s methods applied on ships:

Ford was contacted, given the blueprint from B&C and put his engineers at work. His came back with a plan, which was as expected, revolutionary. He was to create for these a brand new plant on the River Rouge, on the outskirts of Detroit, not far away from his support base and personal, and with an access to the Great Lakes. There, he proposed to create them as products the same way he used for his Ford T, using his mass production techniques, but on a much larger level, and employing the same factory workers.

When completed, the ships would be conveyed through the Great Lakes, via the St. Lawrence River to the Atlantic coast, to reach a port or arsenal, complete fitting out and be commissioned. Ford personally however took little part in their design as ships were not his centers of interest, but he insisted upon even more simplifications in design, and the use of steam turbines rather than diesels as specified by C&R bureau. Ford’s engineers started with known bases due to their lack of experience with ships: The British P-Boats from 1915 and another alternative study for an over-simplified and shortened destroyer design, an austere version of the Flush-Deck destroyers proposed in 1917.

Eagle boats 35 & 58
Eagle boat 35 & 58

At first, Ford engineers created a full-scale model at the company’s Highland Park facility. This mock-up gave the team and Naval officers came to the location time to refine the design an correct flaws, as from the initial blueprint. During these reunions, they decided of the placement of rivet holes and of many other details. In the end, this also helped the dispatched production experts to compose specifications for the future plant, and refined the processes before the plant was even completed (as the walls and floor were erected).

These were sound decisions to ensure the ships were to be quickly built when the plant was completed, however the whole process took precious months to setup. Eventually the blueprints of what could have been called the “SC 200 ft” were approved and in 1918 and the Bureaux hoped that 100 could be delivered by the end of the year. This proved to be optimistic.

Design of Eagle Boats

Design development

As in other such programmes, the issue was to what extent the destroyer-substitute should approach destroyer performance. The General Board wanted a sustained sea speed of 19 knots and depth charges. The original bureau proposal of December 1917 envisaged a maximum speed of 18kts, a cruising speed of 10kts, and a battery of 1-3in/50 and 1-3in/50 AA gun. For a time the design also included a twin 21-in TT, as in P-boat practice, but a gun replaced it in the final design.

In January 1918, the Board reluctantly approved this more austere design, recommending the immediate construction of 100 boats. It went on record that “as in the case of the 110ft chaser it regards the 200ft boat (…) as an emergency design and not one which should be adopted if time and the submarine situation were not of such seriousness.”

In July 1918 the bureaus suggested a 250ft, 650t patrol boat capable of 25kts, and armed with 2-4in, 1-3in AA, a twin 2lin, and a Y-gun, The General Board wanted 5-in guns instead to meet the new 5.9 in reported on the latest U-Boats, and was willing to sacrifice the TTs as well as a reduction to 22 knots, by pairing two turbines instead of just one. There was turbine plant also constructed at the same time the Eagle Boat’s main plant indeed. The board wanted also a radius of action of 4000 nm at 10 knots. To meet schedules, the Board even backed away for other programmes for fear it was to slow down the Eagle Boat programme. The 22 knots prototype ended as being built as a prototype but state secretary Daniels then squashed the programme and nothing came of it.

Hull and general characteristics

These two waves of design simplifications for mass-production proved even more extreme than the Flush-Deck destroyers. It was probably even too extreme for a military vessel, to the point of hampering it to be effective, and they missed the war entirely, being relegated to peacetime routine patrols at home, where their numerous limitations, acceptable in times of war, were no longer in peacetime, so they ended not well-liked.

The ship’s most striking feature was their slab-side hull to simplify the construction process. By eliminating entirely the complex curves of the bow, the ship had straight sides all along, which obliged to create a pear-shaped deck to keep some seaworthiness and fluid lines. The hull itself was made of large separated blocks with straight lines. Each rib section was made of six flat, holed sections to save weight, bolted together like a lego. The hull plates were then welded together to this structure and the connection between the bottom and sides were the only rounded plates of the ship.

As completed they displaced 615 long tons (625 t) for a length of 200.8 ft (61.2 m) a beam of 33.1 ft (10.1 m) and a draft of 8.5 ft (2.6 m). They were effectively substitutes for the more expensive destroyers. And the larger, austere version of the existing flush-deck series proposed in 1917 came close to production as the DD 181 class. They would have been early USN escort destroyers. Overall, the destroyers were clearly much more capable and had priority. The 200-footer had to be designed for minimum interference with other programmes, to be built on the Great Lakes and Inland Rivers, with everything tailored easy assembly, few curves, flat sheer.
Credit is due to the British P-boat, details of which had been brought from England by Stanley Goodall.


Plans changed over time. There was one proposal for traditional VTEs which was quickly dropped, as they were slow to heat up and not that economical for long patrols. Diesels were soon the best choice for C & R. Ford however preferred steam turbines, which was his main contribution to the evolution of the design. In the end they were indeed given the low-power, relatively cheap Poole geared steam turbine, rated for 2,500 shp (1,864 kW). The single turbine was connected to a single propeller shaft, three bladed, for a top speed on paper of 18.32 knots (33.93 km/h; 21.08 mph).
Steam came from two mixed-fired Bureau Express boilers, with 105 tonnes of coal and 45 tonnes of oil carried, the latter injected to speed up the combustion. Total range, a crucial point, was 3500 nautical miles at 10 knots.


The final armament of the Eagle Boats as approved comprised two 4″/50 caliber guns (102 mm) installed on the forward upper deck, roof of the quarterdeck room aft, and one 3″/50 caliber gun (76 mm) on the after deck. In addition two .50 caliber(12.7 mm) Browning M2HB machine guns. They were intended to deal with aviation, but could be used in a duel with a surfaced u-Boat as well.

The proper ASW weapon on board was of course the single Y gun installed however only on the Eagle 4, 5, 6 and 7 only in the serie. Indeed there were no DCR (Depht Charges Racks) at the stern but instead a projector initially created by Thornycroft, able to throw a charge at 40 yd (37 m). The first was installed in July 1917 and tested the next month with success. 351 British torpedo boat destroyers were modernized with this gun, taking part in ASW coastal defence while around 100 lighter craft also were equipped with it.

The name “Y-guns” referred to their basic shape, was studied by U.S. Navy’s Bureau of Ordnance from the Thornycroft model which was passed to them. It was produced and became available in 1918. It was holding two depth charges cradled on shuttles inserted into each arm, like the 1942 DCT (K-Gun). Each charge flew starboard and port, fired by an explosive propellant in the vertical column of the Y-gun, and the USN model was able to reach 45 yards. New London Ship and Engine Company started producing them from 24 November 1917 but they were in short supply, which explains only four were installed on the Eagle boats.

Eagle Boat

7 minutes footage of Ford’s Eagle Boats – National Archives Video Collection

Construction and service

Construction process and issues

The assembly plant of River Rouge was completed in five months. The keel was laid in May 1918. Machinery and fittings mostly came from the already existing Highland Park plant, while the new River Rouge plant was given the steel sheets and parts fabricated in the A-Building. Ford believed it was initially possible to replicate the process chain used for his automobiles. However soo, the size of these ships made it impossible. Instead a “step-by-step” chain was created with a 1,700-foot (520 m) line, supplied on its way by seven separate assembly areas. The line ended in the 200-foot (61 m) extension called B-Building, for pre-assembly.

Shipbuilding was all knew for Ford, more happy with mass-producing trucks for the Army. The Eagles as the result suffered from teething problems: The electric arc welding used on cars did not work as expected and general workmanship was poor, later reduced drastically by the superintending constructor, reduced to watertight and oiltight bulkheads. Ladders were used instead of scaffolds during the bolting of plates, as well as short-handled wrenches prevented the worker to use the right amount of force to bring tightly bond the plates (future leaks). Metal shavings between plates also made this bonding rather difficult and sealing the hull proved extremely difficult.


USS Eagle Boat No.1 was soon renamed PE-1 in 1920. She was launched on 11 July 1918, but commissioned in October 1918. On month later the war ended. After the construction phase, the launch and fitting-out phase proved difficult: The massive 200 feets hulls were moved slowly from the assembly line on specially made tractor-drawn flatcars, then placed on a 225-foot (69 m) steel trestle. The latter were installed alongside the water’s edge, and could be sunk 20 feet (6.1 m) deep using hydraulic power. Warship-grade fitting out included turbines, weaponry, wiring and equipments, to be done after launch, but there was no room available and the ships were to be stockpiles somewhere else.

The contract between Ford and the Navy signed on 1 March, 1918, stated one ship by mid-July, ten by mid-August and twenty by mid-September, and up twenty-five each monthly, then one per day. These figures were never met: The first seven were still not completed by the end of 1918, only the lead boat. The Navy refused them, as they discovered crudely made ships plagued leaky fuel oil compartments and hull plates.
Meanwhile the Ford plant workforce reached 4,380 by July and 8,000 at the end of the war. Ford’s initial optimism over using inexperienced labor was driven by hiring supervision personnel specialized in shipbuilding, but they proved hard to find. Needless to say on November 1918, the contract, which went from 100 to 112, was curtailed to just 60. PE-1 to PE-7 were commissioned in 1918, while the remaining 53 were commissioned in 1919, therefore no longer needed and less useful than destroyers. The name “PE” could be “patrol escort”, but the unofficial name which stuck for all, historians and amateurs alike, was “Eagle Boats”. This came from a wartime Washington Post editorial calling in 1917 after the US entered was for “…an eagle to scour the seas and pounce upon and destroy every German submarine.”

This became a postwar “Eagle Boat affair”: Senator Henry Cabot Lodge of Massachusetts in December 1918 ordered indeed Congressional hearings. Her targeted Navy officials which dismissed charges of taxpayer unnecessary expenditures as the boats were delivered after the end of the war. They argued the boats were a necessary experiment, as first dedicated long range ASW vessels and that Ford profits were modest. The case was closed as the ships found some utilities interwar and were cheap enough to have not been a complete waste. Historian David Hounshell later wrote about the case and argued that they proved that transferring an industrial process in a completely different fields was not something that could be done in emergency and in wartime.

Eagle Boats in the interwar

In the first serie PE 1-PE 112, twelve (PE 25, 45, 65, 75, 85, 95, 105 and 112) were to be transfered to Italy. The last was commissioned on 27 October 1919. The whole serie was cancelled on 30 November 1918 but 60 were effectively delivered and commissioned. Eagle 16, 20-22, and 30 were transferred to the Coast Guard late in 1919. The rest at first served as intended, at least to test the concept.
Reports on their performance at sea were mixed: The use of flanged plates instead of rolled plates facilitated production, an idea of Ford, but which resulted in poor sea-keeping characteristics, which added to never ending leakages problems that plagued the ships.
This was so bad that the most crippled vessels were ordered to stay in harbours, used as stationary aircraft tenders. Some served to support photographic reconnaissance planes used at Midway in 1920 and in Hawaii the next year, until larger and better suited ships replaced them. Eagle boat 34 served a part of the year with the tug USS Koka and was used to capture elephant seals on Guadalupe Island for a Zoo. Slowly but surely, the Navy started to get rid of them. From the early 1930s, they were sold (after less than 10 years of service). This started in June 1930 for the first wave, 1932 for a single ship and the remainder in 1938. Ships were also lost: PE25, Capsized in Delaware Bay squall on 11 June 1920, P10 was destroyed on 19 August 1937 (causes?), PE17 wrecked off Long Island, New York 22 May 1922, Others were sunk as target in 1934: PE 6, 7, 14 and 40.

Eagle Boats in WW2

A single ship stationed in Miami as a training vessel until WW2 and in total, eight Eagle boats served during World War 2. The most famous of these was USS Eagle 56. She was indeed in action during the whole war and was sunk by a German submarine near Portland (Maine) in April 1945, a singular end for a ship that missed WW1 but managed to hunt submarines to end that way a few days before the German capitulation:
USS Eagle 56 patrolled off the Delaware Capes in January 1942 and went on continuously despite her defects during what German submariners called the “Second Happy Time”. The east coast of North America was by then open range for U-Boats which made a massacre. The crew endured months at sea without going on shore, and each time they expended they deep-charges a small ship came from Cape May in New Jersey to bring her supplies, including food and water. USS Eagle 56 notably rescued survivors of SS Jacob Jones off Cape May in February 1942. She collided with the wreck of Gypsum Prince during another rescue on Delaware Bay. She was repaired by scrapping another Eagle boat. She was used at the Key West sonar school in May 1942 and later assigned to Naval Air Station Brunswick from 28 June 1944.

At noon, on 23 April 1945, she exploded amidships, broke in two and sank 3 mi (4.8 km) off Cape Elizabeth (Maine). USS Selfridge was 30 minutes away and came to rescue 13 survivors (from 62). The sonar operator of USS Selfridge then obtained a sharp, well-defined sonar contact. Once she get the survivors on board, she dropped nine depth charges, with no result. A postwar record stated U-853 was to be the ghost submarine, confirmed by five of the 13 survivors even spotting for some a red and yellow emblem on her sail, an insignia that matched U-853’s red horse on a yellow shield. There was also the option of a boiler explosion but none so far had failed. Despite of this, the Navy inquiry concluded to boiler explosion. This was rectified by historians long after and nowadays, USS PE-56 is the sole WW1-era USN sub-chaser sunk by an U-Boat during WW2. No of the other Eagle Boats reported any “kill”, and after 1942 they were likely replaced once escort destroyers and PC-boats were in sufficient numbers.

If there was a merit to the whole serie of Eagle Boats, it was to show “how not to do it” for mass-producing sub-chasers in wartime. The wooden SC 110 ft had none of these problems and served for much longer despite their simpler wooden hull, but industrial difficulties really were the problem. The Navy ended with poor ships of little utility and bad reputation which missed their main objective: Hunting German submarines. A ship designed during WW2 drawn all the lessons in this and proved this time very successful: The PC boats, also called 173 ft submarine chasers.

Read More/Src

Anti-Submarine Warfare in World War I: British Naval Aviation and the Defeat – By John Abbatiello
Naval Weapons of World War One: Guns, Torpedoes, Mines and ASW Weapons of WW1 – Norman Friedman
By Norman Friedman

St Louis class cruisers (1904)
New York class Battleships (1912)

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