Marco Polo (1892)
The First Italian Armoured Cruiser
The Marco Polo was the first Italian armoured cruiser. She was designed by chief engineer Carlo Vigna in 1889, and laid down in January 1890 in Castellamare di Stabia but was closely based on the Etna class cruisers. She was modified during construction as an armored cruiser she was larger and theoretically faster, but without the heavy 254 mm artillery pieces of the Etna. Instead, her 152 mm pieces were complemented by a large 120 mm battery. But this choice led to several criticisms, and the Marco Polo was generally considered too lightly armed. In addition, her expected speed of 19 knots was never reached and remained as slow as the Etna.
HD rendition of the ship (Postcard), wikimedia cc
⚠ Note: This post is in writing. Completion expected in late 2023.
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Design
The ships was longer than the Etna at 106.05 meters (347 ft 11 in) overall versus 283 ft 6 in (86.4 m), wider at 14.67 m (48 ft 2 in) vs 13 m (42 ft 6 in), and the draft was deeper for about 8cm. Overall displacement was 4,583 t (4,511 long tons), much heavier than the Etna class at 3,474 long tons (3,530 t). Propulsion used two vertical triple-expansion steam engines fed by four Scotch marine boilers which produced 10,000 indicated horsepower (7,500 kW) versus 7,480 ihp (5,580 kW). Consequently top speed was rated (in theory) as much as 19 knots versus 17 which was a real progress, but in reality 17.2 knots was the most common figure, as she did 17.8 knots (33.0 km/h; 20.5 mph) at best by overheating its boilers and producing 10,663 ihp (7,951 kW). Radius was 5,800 nautical miles (10,700 km; 6,700 mi) versus 5,000 nautical miles (9,300 km; 5,800 mi) at 10 knots.
The armament seen the deletion of the heavy 254 mm pieces in favor of a concentrated battery of six 152 mm/40 (6.0 in) guns in single mounts which the Etna had already, for a secondary battery of ten rapid-firing single 120 mm (4.7 in) guns. The light battery was about the same, eleven 57 and 37 mm versus ten Hotchkiss revolver guns on the Etna. Its 100 mm (3.9 in) armored belt only stretched to the middle of the ship, starting and ending under the fore and aft ammunition wells. Gun shields and conning tower were protected by 51 mm of armour. Only the deck was protected on the Etna at 1.5-inch (38 mm).
Brassey’s Naval annual depicting the general scheme of the Italian cruiser
Postcard depicting the Marco Polo
Marco Polo used as the ship transport Cortelazzo in 1918 – cdts navypedia.org, from Conway’s Fighting ships 1906-1921
Illustration of the Marco Polo in 1914
Sardegna (1914) specifications |
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| Dimensions | 106,50 (347 ft 11 in) x 14,57 (48 ft 2 in) x 5,88 m (19 ft 3 in) |
| Displacement | 4500 – 4820 t. FL |
| Crew | 394 |
| Propulsion | 2 screws, 2 VTE engines, 4 cyl. boilers, 10 660 hp |
| Speed | 17 knots (31 km/h; 20 mph) |
| Range | 5,800 nmi (10,700 km; 6,700 mi) at 10 knots (19 km/h; 12 mph) |
| Armament | 6 x 152, 4 x 120, 6 x 57, 2 x 37 mm, 2 howitzer, 2 ML, 4 TT 450 mm |
| Armor | Belt 150 mm, Decks 25 mm, CT 51 mm, shields 51 mm |
Links/Sources
On fr.naval-encyclopedia.com
Marco Polo on wikipedia
on navypedia.org
Conways all the world’s Fighting ships 1906-1921
Conways all the world’s fighting ships 1860-1906
