Battle of the Heartwater

Battle of the Heartwater
Part of the Eracuran War
LB Céimíocht engaging Æsthurlav units in the Heartwater
Date 19 March 1944 Location Waters in and around the Ossorian Home Islands Result Ossorian Victory
Belligerents
Ossoria	Æsthurlavaj
Commanders and leaders
Lewella Ní Daimhín Nerys Ní Maoláin Bedwyr Ó Máille	Lyydi Pekkala
Units involved
Home Fleet Third Fleet Eighth Fleet	High Seas Fleet
Strength
247 ships 8 fleet carriers 8 light carriers 17 battleships 6 battlecruisers 23 cruisers 164 destroyers/sloops 21 submarines Many torpedo boats ~1,300 aircraft of various types	71 ships
Casualties and losses
53 ships sunk or damaged ~24,000 casualties

The Battle of the Heartwater (Ossorian Gaelic: Cath an Uisce Croí) was the largest naval battle of the Eracuran War. It was fought in the waters near the Ossorian islands of Oileán Mór, Oileán Scairbh, Oileán Scríofa, and Oileán Glasa, on 19 March 1944, between the Royal Ossorian Navy and the Æsthurlav Navy, as part of Operasjon Sjøherre which aimed to force Ossoria out of the war by destroying the Royal Navy's primary fleet yards at BCB Austell, outside the Ossorian capital city of Kenlis.

By the time of the battle, the Æsthurlav Navy had been worn down by over five years of warfare with the Royal Navy, which had exploded in size and combat strength. Therefore, the Æsthurlav leadership decided to gamble the outcome of the naval war on a single throw of the dice to deal a crippling blow to the Royal Navy, gathering the majority of their remaining surface combatants for a suicidal attack on the RON's primary fleet base at Austell. This attack was decisively repulsed by the RON's Home Fleet and elements of the Third and Eighth Fleets.

The battle comprised three main engagements: the Battle of Aird Laidhre, the titular Battle of Uisce Croí, the Battle of Carbad, as well as dozens of lesser actions throughout the battlespace.

As a result of the battle, the Æsthurlav Navy suffered crippling losses and was unable to resist its systematic destruction by the Royal Ossorian Navy over the remainder of the war.

Order of Battle

Ossorian Forces

Home Fleet: Admiral of the Fleet Lewella Ní Daimhín, commanding

• Task Group 10: Admiral of the Fleet Lewella Ní Daimhín, commanding - battle line
  • LB Cernunnos - Fleet flagship
• Task Group 13: Commodore Eithne Ní Corra, commanding - patrol squadron
• Task Group 14: Commodore Dálach Ó Floinn, commanding - patrol squadron
• Task Group 17: Commodore Mostyn Ó Síoda, commanding - patrol squadron

Third Fleet: Fleet Admiral Nerys Ní Maoláin, commanding

• Task Group 31: Vice Admiral Sinéad Ní Rothláin, commanding - battle line
  • LB Scáthach - Fleet flagship
• Task Group 32: Vice Admiral Gwythyr Ó Cillín, commanding - fleet carrier force
• Task Group 33: Admiral Dónal Ó Laighin, commanding - battle line
• Task Group 34: Admiral Gwenllian Ní Meara, commanding - battlecruiser force
• Task Group 35: Admiral Teàrlag Ní Seanáin, commanding - fleet carrier force

Eighth Fleet: Fleet Admiral Bedwyr Ó Máille, commanding

• Task Group 81: Vice Admiral Callum Ó hUiginn, commanding - battle line
  • LB Taranis - Fleet flagship
• Task Group 82: Admiral Gráinne Ní Cianáin, commanding - light carrier force
• Task Group 83: Admiral Nolan Ó Cuilinn, commanding - light carrier force

Aftermath

Ossoria

The attack, the first penetration of the innermost waterways of the Home Islands by a hostile force in over 375 years, shocked the Ossorian public to the core. Immediately following the battle, overwhelming domestic pressure was placed on the Royal Navy to simultaneously forcefully respond to the invasion and to ensure that a repeat attack would be impossible. The Admiralty stripped the Fourth and Sixth Fleets of many of their ships to reinforce Home Fleet before ultimately disbanding both formations and folding them into the Third and Fifth Fleets. Both fleets were then unleashed upon the Æsthurlav coasts with orders directly from High King Diarmait VII to "destroy every scrap of infrastructure that could support a naval presence of any kind" as well as to pursue "the complete and total eradication of the Æsthurlav Navy as a viable naval force."