U63 class (1916)

Germany: SM U63 to U-65 (1916-17)

The U63 class U-Boats were basically a repeat of the U51 mobilization boats by Germaniawerft in, Kiel. These were only three submersibles launched in February-March 1916 with a rounded prow, rewroked tail, separated deck and double hull, Germanierft diesels and two 8.8 cm guns, although this was changed later in the war. This class was improved during construction (U60 and U99), with better diving time and better diesels, better range and speed, and up to twelve torpedoes. They had an impressive collective tally with the most successful being U63 with 69 merchant ships sunk (192,145 GRT) and a 5,250 tons warship, 3 auxiliary warships, damaging 11 merchant ships and notablu the cruiser HMS Falmouth. In all, they claimed 167 ships sunk, damaged around 20. Only U64 was sunk in action. #kaiserlichesmarine #ww1 #u63 #u64 #u65 #germaniawerft #uboat #uboote

Design of the U63 class:

Germaniawerft’s improvements over the U51.

The U51 class were themselves essentially a repeat of the U41, a long derivative of the excellent U31 class, considered the best design by Germaniawerft. They were double-hull U-Boats part of the mobilization program (Ms type). The U51 were laid down in the summer of 1914 and commisioned from November 1915 to April 1916 with improvements in diving time, down to a minute and 45 seconds, but they also stuck to the standard design with a well deparated pressure and inner hull. The U41 revised management of the ballasts and water scoops to reach a better diving time, and answer’s Danzig NyD own U43 series. Danzig also improved range and underwater performances, but Germaniawerft’s U51s remained ahead on the matter.

The U63 compared to the U57 class mixed elements from previous types with features already well mastered from the yard, but Germaniawerft remained relatively conservative compared to the U43 class and its completely rounded hull. A thord actor that came in was AG Weser, which basically copied the Germaniawerft boats, with sitll a well separated outer hull deck and lower outer hull plus flattened upper section. The conning tower was larger on U63 compared to the U51 but the design remained essentally the same. The U63 class was not known to improved much in diving time but it was much larger, going from 715 to 810 tonns standard, the first Germaniaweerft’s submarine to pass the bar of 800 tonnes.

Hull and general design

Plans of the U63 class. The original colored version is easy to pickup on internet.

The U63 class displaced 810 t (800 long tons) surfaced and 927 t (912 long tons) submerged for an overall lenght of 68.36 m (224 ft 3 in) (o/a), and a pressure hull 55.55 m (182 ft 3 in) (pressure hull) long, in beam they reached 6.30 m (20 ft 8 in) overall for a 4.15 m (13 ft 7 in) wide pressure hull. The height from the keel to the top of the CT without persicopes or telescopic antennae was 7.65 m (25 ft 1 in) for a draught of 4.04 m (13 ft 3 in). To compare the U57 displaced 786 t/956 t for a hull 67 m long overall. The pressure hull was barerly shorter at 54.22 m. But they had a greater beam at 6.32 m and lighter draught at 3.79 m while being also taller overall 8.05 m (26 ft 5 in). U63

Design-wise, she had a rounded prow, instead of the classic straight one, a new discovery of pool tests with models. This new rounded prow was largely adopted as it created less turbulences and thus, underwater drag at speed. The prow was composed also of a rounded chin, with a straight section at the waterline. To improve sea keeping, the deck was raised substantially forward above the torpedo tubes. The design was relatively wide, with a ratio way more pronounced than slender WW2 U-Boats, and the outer hull, flattened on top, a classic feature of more ancient U-Boats unlike Danzig’s revolutionary U43 class, met the flat sides raised deck with gentle slopes and cutouts water scoops running all the war to the tail.

The double hull was composed of 13 separate compartments, with two ballast tanks fore and aft (6 in all), with two more amidship, two regular tanks, and four oil tanks. The pressure hull was of course not a straight tube. It was narrow forward, meeting the pair of torpedo tubes, and aft of them were a pair of 1.3-1.4t torpedo compensating and aft, a 2.13t trimming tank and a 1.36t drinking water tank, all under the deck. The dive planes were located below the waterline and leaf-shape, with their axis directly below the forward tubes.

Next was the second pressure hull compartment with the commander’s cabin and officer’s , warrant officers mess, sanitaries and the galley plus a 600 kgs distilled water tank next to these.
The control room was next, behind a concave bulkhead, with three periscopes (a novelty, the norm was two), including one smaller backup periscope in front of the CT the two others were internal, passing though the conning towing bell protruding from the pressure hull above, with a tall and slender navigation periscope and an attack one. There was a tank of drinking wter below deck.

Then came a convex bulkhead separating the Control Room from the larger engine room. This was the beamiest part of the pressure hull, containing the tw diesels side by side, close to oil fuel ready use tanks and distilled water tanks aside, because below deck were located the battery. A thin separation led aft to the electric engines and motor room, and the aft bulkhead separating the machinery room from the aft torpedo room, which narrowed up. The shafts were supported on small struts. The design of the outer CT was conventional, with a “spine” running at the base of the CT, then a bridge and small hatch to enter the CT bell. The crew was 36 strong including officers, 4 or 5, and there was a small boat encased under deck.

Power plant of the U63 class

The U63 class sported two in-house Germaniawerft diesels, two-stroke 6-cylinder, rated for a total of 2,200 PS (1,618 kW; 2,170 shp) surfaced, and completed by two Siemens-Schuckertwerke (presumably) rated for 1,200 PS (883 kW; 1,184 shp) submerged on 2 shafts ending with three bladed propellers. Top speed was slightly inferior to the U51 class at 16.5 knots (30.6 km/h; 19.0 mph) surfaced versus 17.1 knots and slightly lower underwater at 9 knots (17 km/h; 10 mph) versus 9.1 knots.

Range was based on a fuel oil tank from 115 to 118t, making for a slightly better 9,170 nmi (16,980 km; 10,550 mi) at 8 knots (15 km/h; 9.2 mph) surfaced and 60 nmi (110 km; 69 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged. They were still the best-performing U-Boat of that era, compared to the Dantzig and Bremen boats. Diving time remained the same as well as their useful diving operating depth.

Armament

On this topic, the U63 class still featured the same two pairs of 50 cm tubes fore and aft (19.7 inches) and eight torpedoes in reserve, including the ones already preloaded (so four spare). Originally they kept two 8.8 cm main guns, on either side of the conning tower on sponsoned platforms. But later a 10.5 cm SK L/45 was subsituted as standard to the forward 8.8 cm gun.

Torpedo Tubes

Germany started by equipping its torpedo boats and early U-Boats of the 1890s with the 35cm (14 in) C35/91 and C35/91GA, then 45cm (17.7 in) C45/91 Br, C45/91S, C/03 and C/03 D were reserved for surface ships, and the C/06 and C/06 D for U-Boats from U3 onwards. They stayed standard before the introduction of the 50 cm. The initial model was reserved for surface ships. This was the (19.7″) G/6 and G/6D which used either the Decahydronaphthalene (Decalin) or Kerosene Wet-Heater.

From U23 onwards, all U-Boats came equipped with the new and famous G7 (entering service in 1913), repeated by the U27 class and follow-up classes. Still, there were important stocks of G/6, mostly now used for training or tests. The Kerosene powered G/6D was considered too “temperamental” for submarine use indeed. The G/6 was developed from 1908 and entered service in 1911. The Royal Navy was slower on this chapter, only introducing the 21″ (53.3 cm) Marks II, II* and II** for submarine use from 1914 onwards. The four 500 mm (19.7 inches) torpedo tubes could be reloaded from above via the larger hatches going through the outer upper hull.

G7 Torpedo

The G7 was designed in 1910 and entered service in 1913. Originally designed for surface ships, but in 1917 it started to be used on U-boats.
Specs:
Weight: 3,009 lbs. (1,365 kg)
Overall Length: 276 in (7,020 m)
Explosive Charge: 430 lbs. (195 kg) Hexanide warhead
Range/Speed settings: 4,370 yards (4,000 m)/37 knots and 10,170 yards (9,300 m)/27 knots
Power: Decahydronaphthalene (Decalin) Wet-Heater

8.8 cm Schnelladekanone Länge 30 naval deck gun

For the U19 onwards, the classic 3,7 cm or 5cm deck guns were ditched out and as U19 was considered large and stable enough to have a larger gun installed and a single 88mm 27 calibre TK L/30 C/08 deck gun was installed forward. For this the deck was reinforced but no sponsons extensions appeared seemingly on photos.

In 1916, after captains reported this gun still weak, notably to scuttle a boarded ship or engage an armed trawler. They spent way too much time sinking their prey, which called for enemy reinforcements. Thus, all four boats had a second 8,8 cm deck gun installed aft, making two. U19 was the first U-Boat class with two guns, fore and aft. This was repeated for the U23 and U27 classes in wartime. U30 exchanged both guns for a single 10.5 cm/43 TK L/45 C/16 deck gun in 1918. The 8.8 cm became the standard go-to gun for all U-Boats built afterwards, until the U87 class (launched 1916), generally two for oceanic boats, one for minelayers and for later coastal subs. They accounted for many of their preys.

The 8.8 cm SK L/30 gun used the Krupp horizontal sliding block, or “wedge” and the submarine deck version was on either a retractable or fixed pivot mount. The Krupp mount retracted vertically through a hatch, and the Erhardt version folded down onto the ship’s deck. They avoided underwater drag and turbulences. It seems U19 class had the Ubts.L of the second type.
The 8.8 cm SK L/30 was a widely used naval gun on World War I pre-dreadnoughts, cruisers, coastal defence ships, avisos, submarines and torpedo boats in both casemates and turrets as well.
This calibre became so ubiquitous in the German Navy it was still a favourite for WW2 U-Boats as well starting with the Type VII. Read more The U57 class carried 276 rounds for both guns originally.

Specs 8.8 cm SK L/30 on Ubts.L mount

Weight: 644 kilograms (1,420 lb)

Overall length: 2.64 meters (8 ft 8 in).
Breech: Krupp horizontal sliding block
Shell: fixed 7 kg (15 lb) cal 88 mm (3.5 in)
Elevation: -10° to +30°
Rate of fire: 15 RPM
Muzzle velocity: 590 m/s (1,900 ft/s)
Maximum firing range: 7,3 km (8,000 yd) at 20° or 10,5 km (11,480 yards) at 30°

10.5 cm SK L/45 naval gun (1916)

In late 1917 and 1918, some boats traded their two 8,8cm deck guns (or single one) for a single 105mm deck gun with 300 rounds. The crew rose to 46-48 men less four officers, now with a proper gunnery officer.
Built by Meddinghaus, this heavy deck gun was designed specially for deck use, low, with many sensible elements protected from corrosion.

Specs 10.5 cm SK L/45

1,450 kg (3,200 lb), 4.725 m (15 ft 6.0 in), 6.8 mm (0.27 in) wide.
Shell 10.5 cm (4.1 in) 25.5 kg (56 lb) fixed Brass Casing 17.4 kg (38 lb)
Breech: Horizontal sliding-block, MPL C/06: -10° to +30° mount
Rate of fire: 15 RPM
Muzzle velocity 710 m/s (2,300 ft/s)
Effective range 12,700 m (41,700 ft) at 30°

Author’s rendition of the U63 class

⚙ U63 specifications
Displacement	810 t surfaced, 927 t submerged
Dimensions	68.36 x 6.30 x 4.04 (224 ft 3 in x 20 ft 8 in x 13 ft 3 in)
Propulsion	2 shafts MAN diesels 1,800 PS surfaced, 2× AEG EM 1,200 PS submerged
Speed	16.5 knots (30.6 km/h; 19 mph) surfaced, 9 knots (17 km/h; 10 mph) submerged
Range	9,170 nmi (16,980 km) at 8 knots surfaced, 60 nmi/5 knots submerged
Armament	4× 50cm TTs (2 bow, 2 stern, 8 torpedoes), 2x 8.8 cm SK L/30 gun*
Max depth	50 m (160 ft)
Crew	5 officers + 31 men

Career of the U63 class

The U-Flotilla Pola was formed on 18 November 1915 from the previous German U-Half-Flotilla Pola, which had been set up on 1 July 1915. In June 1917, after the arrival of additional boats, it was renamed U-Flotilla Mediterranean and finally split on 1 January 1918 into the I. U-Flotilla Mediterranean (in Pola) and the II. U-Flotilla Mediterranean (in Cattaro). All three sisters had the distinction of seeing service there.

U63 (1916)

Otto Schulze U63 was ordered on 17 May 1915 at Germaniawerft in Kiel as Yard number 247, laid down on 30 April 1915, launched on 8 February 1916 and commissioned on 11 March 1916 under Kptlt. Otto Schultze until 27 August 1917 for training in the IV Flotilla until 6 November 1916 and then she briefly served until 11 Nov 1918 at Pola with the Mittelmeer I Flotilla. From 15 October to 24 December 1917 she was still with the Pola Flotilla. Schultze was replaced by Kptlt. Heinrich Metzger from 28 August to 14 October 1917 and then Kptlt. Kurt Hartwig from 25 December 1917 to 11 November 1918 when she was surrendered to the allies. Both Schultze and Hartwig were awarded the blue max (Pour le Mérite).

U63 operated with the IV U-boat Flotilla in 1916 and subsequently to the I U-boat Flotilla in the Mediterranean until 1918. She conducted twelve combat patrols in the Mediterranean and eastern North Atlantic, sank a total of 70 merchant ships* of the Entente and neutral states for 194,208 GRT and sanking a major warship on August 20, 1916, the British light cruiser HMS Falmouth (5,250 GRT) of the Town class, off the east coast of Britain by a single torpedo. Eleven sailors were trapped and drown in her hull. The cruiser had already been damaged shortly before by U-66. U-63’s voyages at some point brought her to coast of Egypt thanks to her great range, and she sank there the small sailing ship L. Rahmanich (79 GRT) on March 26, 1917.

Captain Hartwig The largest ship sunk was the British troop transport Transylvania of 14,300 GRT on May 4, 1917, 2.5 miles, south of Cape Vado, Ligurian Sea. 400 died in the tragedy. The second largest was the French liner Magellan on 11 December 1916 (6,027 GRT). In addition to HMS Falmouth she also sank the flower-class sloop HMS Rosemary on 4 July 1916, it was in fact her very first victim. In addition, she also sank three auxiliary warships for 6,020 GRT: On 6 November 1917 HMS Peveril (1,459t), damaged on 8 November 1917 HMS Candytuft (1,290t), and sank on 3 December 1916 HMS Perugia (4,348t). In all she also damaged 11 merchant ships (47,700 GRT). Measured by total tonnage sunk U-63 became the sixth top scorer for ocean-going submarines in the First World War. U 63 was delivered as war reparation to Great Britain on 16 January 1919. and scrapped in 1920 in Blyth, northern England.

hms falmouth 1910
HMS falmouth, “hard as nails”. On 19 August 1916 she was already torpedoed by the ambushing U-66 at about 16:05, two hits. She was crippled, badly damaged and listing, but her crew evacuated by the trawler Cooksin while the team staying behind managed to cope with the damage so shat she managed to steam by night at 2 knots back home assisted by two tugboats. At noon U-63 spotted her, launched two more torpedoes which was the coup de grace afetr staying 8 hours afloat and managing to join Flamborough Head in Yorkshire. A single crewmember was lost and another later due to his injuries. This added to her action at Jutland.

U64 (1916)

Kapitanleutnant Moraht U64 was ordered on 17 May 1915 at Germaniawerft as Yard number 248, laid down on 19 May 1915, launched on 29 February 1916 and commissioned on 15 April 1916. She trained from there under Kptlt. Robert Moraht until 19 Nov. 1916 in the IV Flotilla and started operation with this captain until 17 June 1918, being transferred in November 1916 to Pola/Mittelmeer I Flotilla. Her long range enabled long cruises from Gibraltar to Alexandria and the Aegean sea. ASW defences were not well organized still in 1916 so she met succes as well, sinking 45 ships sunk for a total of 129,570 tons, damaged three for 9,420 tons, taking one as prize of 186 tons. Her biggest kill was the 18,300 tons Danton for which Robert Moraht was awarded a Pour le Mérite.

On 19 March 1917, while on patrol in the Tyrrhenian Sea she spotted the French battleship 30 nautical miles (56 km; 35 mi) south of Sardinia. She maanaged to take an interception course, and launched both bow torpedoes, with at least one hitting the mark. The semi-dreadnought was designed before U-Boat threat was a thing, and poorly defended against flooding. Her bulkheads somewhat held up however for her to sink in 45 minutes, enabling most of the crew to escape, but she still went down with the loss of 296 men.

Danton

The ill-fated Danton, a semi-dreadnought delaying the French entry into the dreadnought race by years, “punished” despite her 16 watertight compartments, relatively adequate in 1900 against 12 or 18 inches torpedoes but not above. Her sister Voltaire survived two hits however.

Other than Danton, U64 also sank on on 9 June 1917 the Italian steamer Fert of 5,567 GRT, and on 30 January 1918 the British 13,528t steamer Minnetonka. On 12 September 1917 she “bagged” the 5,395t US steamer Wilmore and on 19 October 1917 the British 5,174t War Clover. In total she sank 44 merchant ships sunk (129,327 GRT), sank a 243t auxiliary warship, damaged three merchant ships for 9,420 GRT and took as prize a small merchant ship in 10 patrols but met her fate when attacking a convoy between Sardinia and Sicily on June 17, 1918. North of Cape Bon, she was forced to surface after sustaining damage from two depth charges, with flooding causing her to slump bow-heavy. According to the British account, after surfacing, the she was rammed by the Lychnis, fired upon by HMS Partridge, sinking at 38° 7′ N, longitude 10° 27′ E and her crew had no tome to man her deck gun. Only 5 of the crew survived, in the CT when she emerged, the commander Robert Moraht, an officer of the watch and three sailors. The remaining 37 went down.

U65 (1916)

Captain Siess U-65 was ordered on 17 May 1915 at Germaniawerft, as yard number 249, laid down on 4 June 1915, launched on 21 March 1916
and commissioned on 11 May 1916 under Kptlt. Hermann von Fischel, training with the IV Flotilla from 2 July to 18 November 1916 and she was sent to the the Mediterranea, joing like her sisters the Pola or “Mittelmeer I Flotilla” until her scuttling on 28 October 1918. She had the second largest tally in class, managing in 11 patrols so sink 47 merchant ships (75,280 GRT), one 1,498 GRT auxiliary warship and damage 3 merchant ships (8,402 tons) under also Kptlt. Gustav Sieß from 19 July to 29 September 1918 and Kptlt. Clemens Wickel from there to 30 28 October 1918. Her largest kills were on 17 February 1917 the 12,644t French steamer Athos, on 26 May 1917 the 5,317t Umaria.

On 11–14 July 1916 she was in her first North Sea patrol, with a second on 16–24 July 1916 and third on 17–21 August 1916 in which she attacked the British minesweeper Haldon 20 August.
On 3–4 September 1916 same, but needed repairs and fixes at her return. On 26 October and until 19 November 1916 she was sent to the Mediterranean, making her crossing and chashing with the armed yacht Valiant II. On arrival at Cattaro she joined the Pola-Cattaro Flotilla, making a first sortie on 28 November, until 7 December 1916 and “probably” sank a steamer. On 4 December she sank the SS Caledonia, but the latter managed to ram her and she returned home for repairs after surfacing.

On 17 February 1917 she sank the troopship SS Athos as seen above, making 754 casualties. She had another patorl from 29 March to 19/20 April 1917 in the western Mediterranean, bagging 4 steamships and 5 sailing vessels. On 14 May to 9 June 1917 she damaged the cruiser HMS Dartmouth by torpedo on 15 May and later sank 7 steamers and 12 sailing vessels in the central Mediterranean. On 6 June she was reported off Cape Passaro and a day later close to the Straits of Messina. She was likely attacked by seaplane. She made another cruise from 10 to 31 January or 1 February 1918, sinking 2 steamers and 1 sailing vessel, attacked by seaplaned and depth-charged by Campanula, but missed her by torpedo. In September 1918 she sank 4 steamers and damaged 4 but by October she was scuttled by the Germans at Pola or Cattaro to avoid allied capture.