NRP Adamastor (1896)

Unprotected Cruiser (1895-97) service until 1933.

NRP Adamastor was a small unprotected cruiser of the Portuguese Navy initially planned in 1890, but funded later by public susbcription. She was laid down in Italy at Livorno in 1895, launched in 1896, completed in 1897, the first of her kind in Portugal. She remained active until her decommission in 1933, taking part of the 5 October 1910 revolution seeing the fall of the monarchy, and colonial endavours in Portuguese Africa in World War I.

adamastor 1927

Development

NRP Adamastor is the first of a serie of WWI vessels, exposed here in 2025 with the British-Built coastal battleship Vasco da Gama (1875), used as Guard ship at Lisbon and still around in 1935. The first modern, albeit unprotected cruiser of the Portuguese Navy was ordered decades later in Italy, NRP Adamastor. She was the first of a series of five cruisers entering service with the Portuguese Navy prior to WWI, the Sao Gabriel class (1898), Dom Carlos I (1898), Rainha Dona Amelia (1899), next to be covered, the former three built in France and Britain, and the last in Portugal. For context in the 1880s, the Ironclad Vasco Da Gama was shouldered by a few ageing masted frigates and corvettes to protect and patrol a 800,000 square miles empire. To be precise, Two 28-guns steam frigates, one 14 guns corvette, six 26 guns wheeled steamers. In 1870, the ships of the line Vasco da Gama (74 guns), Dom Fernando (50), and three 14-guns sailing corvettes.

In 1890, so two decades after, these steam frigates, corvettes and wheeled steamers were still there, but there was nothing modern and adequate for overseas deployments. It was time for a new naval plan, which was quite ambitious in 1890. The expansion of the Portuguese Navy was initiated by a decree from King Carlos I on 20 March 1890. The plan called for the construction of four coastal defence ships and ten cruisers, some intended for service in the Portuguese colonies. However, the country’s bankruptcy in 1892 halted these ambitions. Eventually construction of cruisers was still granted, but postponed until 1895 for the first, and more in 1896-97.

For context, Portugal was ruled by the constitutional monarchy under Luís I of Portugal until 1889, then his son Carlos I of Portugal. This was not an absolute monarchy as there was a parliament, with the “Rotativismo System” seeing two main parties alternated power, the Regenerators and Progressives. But elections were often manipulated, meaning real democratic participation was limited. By the late 19th century, many Portuguese viewed the system as corrupt and ineffective, producing growing public frustration and loss of confidence in the monarchy.
On the other hands, the monarchy kept its Imperial Ambitions and the African Question (which raised the question of the Navy), and the 1880s were dominated by Portugal’s attempt to rebuild prestige through empire.

But the “Pink Map” (Mapa Cor-de-Rosa) was mostly a dream. Claims for a vast territory connecting Angola and Mozambique across central Africa clashed with French and British expansion. The 1890 British Ultimatum became the defining crisis of the era, seen as a national humiliation, triggering massive protests in Lisbon and deeply weakening the monarchy’s legitimacy. It fueled nationalism and strengthened republican movements, and largely was the result of the lack of naval assets to make these claimed anything realistic, when facing the Royal Navy.

That was the trigger for the 1890 naval plan, but it petered out quickly in the face of stark Economic Conditions: Portugal remained one of Western Europe’s poorest countries with a heavy foreign debt (especially to Britain), low industrialization, rural poverty, dependence on agriculture and colonial trade, so much so that in 1892, Portugal effectively declared partial bankruptcy (debt default), worsening political instability and putting an end to its naval ambitions… The next decade would see the rise of Republicanism, culminating with the revolution of 1910.

Design of Adamastor

Despite this context, enough funds were agreed upon at the Parliament to order a first cruiser in Italy, at the time the cheapest proponent. This first cruiser was really built on the cheap, unprotected (all the follow-up cruisers were protected), small, so much so that in WWI she was no more than a glorified gunboat. Anyway, she was a cruiser still, of a type that was common at the time (unprotected cruisers), one rank higher than a gunboat and a question of prestige and presence in any waters. Unprotected cruisers were mostly a deterrent against foreign gunboats and a diplomatic cudgel with guns to bear on any recalcitrant tribe or any coastal city.

Due to the 1890 crisis with Britain, Portugal rejected the obvious order to British yards, fearing the order would be blocked in case of a new crisis, and chose Italy instead, cheaper than the alternative, France. The ship was originally part of the royal decree of 20 March 1890 naval program, and after the 1892 economical collapsed, it was postponed as even the most modest budget could not be voted upon. Instead she was funded by public subscription. This order passed to the Italian Cantiere navale fratelli Orlando in Livorno. This campaign of public subscription was largey fuelled by the press, and intended to “avenge the Portuguese humiliation”. Her keel was laid on 1 January 1895, she was launched on 12 July 1896, completed for trials in May 1897 and entered service on August 3, 1897, named after the mythical sea spirit “Adamastor” from Portuguese literature. Construction in British and international publications like Brasseys, was evaluated to 80,000 pounds sterling.

Adamastor was small but not completely unprotected, despite most sources cited her as such. She had indeed a partial armored deck, only protecting the vitals, machinery spaces amidships and ammunition spaces forward and aft. There was not the usual internal turtleback over the entire waterline lenght of the hull. Despite her limited size and limited firepower, she proved to be a successful vessel for her intended colonial policing, reliable, and having the longest career of all Portuguese cruisers. One surprising asset was her apparently outdated cylindrical boilers characterized by low risk and ease of maintenance repair, for a “sufficient” speed. The Portuguese liked her so much, her characteristics became a model for next two cruisers (Sao Gabriel class), after a competition seing them ordered at the French Normand shipyard, two fully protected cruisers this time, but still small at 1770 tonnes. The real game changer was the Armstrong-built 4,200 tonnes Dom Carlos I later as relations improved with Britain.

Hull and general design

Model of the ship at Lisbon Naval Museum
Adamastor had the typical architecture for cruisers of that era, and the Itaians, which also ordered a few cruisers in Britain, knew the recipe. The hull wa slargely symmetrical, with a raised fore and aft decks, single guns mounts on both, the remainder on the upper deck amidships protected by a tall bulwark in sponsons. The stem had a ram, the stern had a clipper style, narrow at the waist with with fine lines above the rudder and a decorated poop, loke the top stem showing the Portuguese coast of arm and a recall to the “monster”. The military foremast was located forward of the small bridge, and this was followed by two tall, slightly sloped funnels and a sternmast of the same height. Both masts had fighting tops and a searchlight doubling as spotting top as well. These masts had two yards and spankers as for a schooner rig, but rigging was never mounted or planned. Instead she received wireless radio cables as soon as available.

The underwater part of the hull was covered with wood and copper sheating to facilitate maintenance in colonial service far from facilities likes drydocks, a coating better suited for hot tropical waters teaming with life. The hull was divided into 23 watertight compartments plus double bottom, in steel. Normal displacement was 1,729 tons, but other publications also gives 1,962 tons or even 1,993 tons. Conways sticks with 1,729 tonnes as most common sources. Her length between perpendiculars was 74 meters, possibly 76.2 meters overall in some sources for a beam of 10.72 meters, draft of 4.65 meters and crew of 237.

Powerplant

Boilers and VTE engines of Adamastor – The Engineer 1898.

NRP Adamastor was powered by two or four cylindrical engines located in separate watertight compartments for a full rating of 4,000 horsepower (2,983 kW). These VTE looked for the time a bit obsolete, but they proved very reliable and easy to maintain albeit these made for a limited top speed of a max theoretical speed of 18 knots (33 km/h; 21 mph). In reality, this was initially stated as 16 knots. Only the 4000t Dom Carlos reached a more respectable 22 knots. To be more precise, initial design speed was rated at only 16 knots at natural draft, but 17.3 knots at forced draft, but she exceeded this on trials at 17.19 knots and 18.04 knots on forced draft respectively, from an indicated power (ihp) of 4,030 hp.

The VTE were fed by four cylindrical fire-tube boilers working at an operating pressure of 10.9 atmospheres (160 psi). She carried 400 tons of coal (conways states 420 tonnes), for an endurance for some publications of 4600 nautical miles (8,520 km, 5,300 mi) at 10 knots. Her equipment also included two generators rated for 65 V and 110 A, but powered by steam engines. So she had no power at all when anchored, boilers cold. This electricity fed the two boiler room fans with 2 hp motors to force air draft and the two 400 mm diameter searchlights using Pasqualin lamps. The gun mounts were all manual in traverse and elevation.

Protection

There was some protection still, as seen above, but it was limited to a deck 30 mm (1.2 in) thick, and a Conning tower forward below the bridge, that had walls 65 mm (2.6 in) thick, to stop shrapnels from shore field guns or gunboats light guns like a 3-inches caliber (76 mm). The deck was flat, and not subsititute for the sloped turtleback all along the hull. ASW protection existed since the ship was compartimented by 22 watertight bulkheads all the way from the keel to the main deck and double hull. The largest space was for the machinery. Protection of the ammunition magazines is only conjectural since it is decribed as “partial”. Some sources described this as a “cap” over the engine room, protecting protruding steam engine cylinders with a 30 mm thickness. The main gun hoods like the CT were protected by 63 mm or armor.

Armament

Armament was always left as a choice to a nation that ordered a cruiser in a shipyard at the time, as well as the steam engine type and brand, albeit for practical reasons to not generate delays, it was chosen most often to stick with the powerplant proposed by the yard itself (here Orlando). But since Italian guns designs of the time were strongly linked to British designs, Portugal chose Krupp guns, which had an excellent reputation at the time. The remainder was relatively usual for the time, with light anti-torpedo armament, torpedo tubes and even dismountable Nordenfelt pintle machine guns that could be installed on her twop steam pinnaces to support a landing party, one of her primary colonial roles. She also had a generous small arms store to equip a hundred sailors or more.

15 cm Krupp guns

The main armament consisted of two single 15 cm Krupp guns (actually 149.1 mm) in mounts with protective hoods, on the fore and aft decks (forecastle and sterncastle). The Portuguese designated them as the K.15/30. Nominal length was indeed L/30 or 30 caliber, but these old guns had a low rate of fire. The barrel length was actually 27.1 calibers, so even shorter than the 30 announced, making for a light gun, but lower velocity. Range is unknown. They fired 39 kg AP shells or 40.4 kg HE shells. According to some publications when the cruiser was modernized in 1922, they were later replaced with French Canet guns of the 120mm/44 A(tr)12/45 type to standardize artillery across the fleet.

105 mm Krupp

This pair was supplemented by four single 105 mm Krupp quick-firing guns, located in two outer side sponsons on the main deck amidship on each broadside so to have eneough traverse to fire respectively forward or aft. In Portugal, they were designated K.10.5/40. Nominal length was L/40, actual was L/37.4. They fired 14 kg HE shells. Range is unknown.

65 mm L/40

The light armament comprised at first, four 65 mm L/40 guns in broadside mounts, on the same deck amidships, inner battery. They are generally described as French 65 mm Hotchkiss QF guns, designated H(tr.)65/40in Portugal and firing 4 kg shells.

37 mm revolver

Most sources agree they had also two 37 mm revolver guns, Hotchkiss 25mm/25 multi-barrel mounts. Adamastor in some publication is seen carrying two 9-pounder (probably 5 cm) Krupp guns likely made to be mounted on undercarriages for landing parties. Period publications list also two Nordenfelt machine guns on pintles, possibly usable also for landing parties, from the steam cutters.

Torpedo Tubes

The armament was completed by three single 356 mm (14 inches) torpedo tubes, likely Whitehead models by the intermediary of an Italian company. One was fixed in the bow, two were rotatable on the deck, on each broadside.

⚙ specifications
Displacement	1,729 long tons (1,757 t)
Dimensions	73.8 x 10.7 x 6.5m (242 x 35 x 21 ft)
Propulsion	4 VTE cylindrical boilers
Speed	18 knots (33 km/h; 21 mph)
Range	4,600 nmi (8,500 km; 5,300 mi) at 10 knots
Armament	2× 150 mm Krupp, 4× 105 mm Krupp, 2× 47 mm Hotchkiss, 2 MGs, 3 TTs
Protection	Partial deck 30 mm, CT & Gun shields 63mm
Crew	237 officers and ratings

Career of NRP Adamastor

Adamastor in Shanghai, 1927 (colorized). Note her appearance changed little over decades.
Adamastor had her commissioning ceremony with her Portugiese staff and crew on August 2, 1897, in Livorno. On August 3, she sailed for Portugal and arrived in the middle of a parade, immortalized by a paintining now at the Portuguese Martitime Museum. She was greeted indeed as the newest ship in the fleet and for a time, initially used for ceremonial purposes. In 1898, Adamastor started a long flag showing cruiser, representating Portugal in Brazil (former colony), Uruguay, Argentina, Angola, and the Cape Verde Islands. She then toures Portuguese colonies.

She was however recalled at home when dometic troubles commenced due to the Republican faction taking on the offensive for a regime change. Adamastor, initially loyal to the Monarchic regime on paper, would play a leading role in the Republican Revolution of October 1910. She was stationed in Lisbon with the cruisers Sâo Rafael and Dom Carlos after the crew arrested some of the most hardline loyalist officers. Lieutenant José Mendes Cabeçadas became the new ship leader. Three shots from the new revolutionary Adamastor at the Royal Palace of Necessities on October 4th, signaled the start of the revolution. A story that recalls Aurora at St Petersburg a few years later in 1917.

Along with Sâo Rafael, Adamastor shelled the Royal Palace, and sent a landing party. Sailors clashed with Royal guards and lotalist troops in the city but won, leading to the overthrow of the monarchy in Portugal. On October 31st, Adamastor was sent on a cruise to South American countries under a new flag in order to gain international recognition for the new Portuguese Republic.

She was still active, but never modernized, in World War I, under neutrality conditions. She primarily escorted military transports to Mozambique in 1914 and 1915, as revolt grew and the new Republican wanted to keep the Empire, vital to the country’s economy. After joining the war on the side of the Entente, Adamastor started to look at German shipping along Western Africa from northern Mozambique. On May 21, 23, 27, she shelled German outposts on the Rovuma River, sailors taking part in landing party, with 4 killed, 18 wounded, 5 missing in action. In the following months, Adamastor remained in Mozambique and by June 1916, she covered the evacuation of Portuguese troops from the country, took gold supplies from the colony. Back home postwar, she awarded the Order of the Tower and Sword.

In the interwar, it was clear that Adamastor was not a threat to anyone, but she was still useful in the colonies. In the 1920s, she remained the only Portuguese cruiser in operation, “modernized” in 1922, which was limited to the replacement of her 149mm/27 Krupp main guns, now antiquated, by two 120mm/44 A(tr)12/45 Canet guns. In 1926, she represented Portugal at the World’s Fair in Philadelphia in the USA. By the early 1930s with a very low combat value, she was stationed in Macau. With the Japanese intervention in China, she landed a party in Shanghai to protect Portuguese citizens and interests. On June 18, 1932, she was downgraded to a second-class warship. From March 8 and July 1, 1933 now in poor technical condition, she made a last farewell trip from Macau to Portugal at just 4 knots. After her arrival on October 16 she was struck from the list, sold for scrap in April 1934, the last of a breed of early cruisers that disappeared long ago, and last Portuguese cruiser ever.

Gallery

Adamastor in Livorno, just completed.

Same.

Adamastor arrived in Lisbon, painting at the Museum

Adamastor in formation, 1903

Adamastor, date unknown, dark hull, src Reddit

Vasco Da Gama and Adamastor on the Tagus, 1914

Adamastor in Hankeou, China, interwar

Adamastor in Shanghai 1927