Second Thomas Shoal
Reef in the South China Sea
Second Thomas Shoal, also known as Ayungin Shoal (Filipino: Buhanginan ng Ayungin, lit. 'sandbank of silver perch'), Bãi Cỏ Mây (Vietnamese) and Rén'ài Jiāo (Chinese: 仁爱礁/仁愛礁), is a submerged reef in the Spratly Islands of the South China Sea, 105 nautical miles (194 km; 121 mi) west of Palawan, Philippines. It is a disputed territory and claimed by multiple nations.
The reef is occupied by a garrison of Philippine Navy personnel aboard a ship, the BRP Sierra Madre, that was intentionally grounded on the reef in 1999 and has been periodically replenished since then.
History
The atoll is one of three named after Thomas Gilbert, captain of the Charlotte:
First Thomas Shoal – 09°19′N 115°56′E, South of Second Thomas Shoal.
Second Thomas Shoal – 09°44′N 115°52′E, Southeast of Mischief Reef.
Third Thomas Shoal – 10°54′N 115°56′E, Northeast of Flat Island – some distance North of Second Thomas Shoal.
Geographical location
Located south-east of Mischief Reef (09°55′N 115°32′E), Second Thomas Shoal is near the centre of Dangerous Ground in the north-eastern part of the Spratly Islands. There are no settlements north or east of it. It is a tear-drop shaped atoll, 11 nautical miles (20 km; 13 mi) long, from north to south and fringed with coral reefs. The coral rim surrounds a lagoon, which has depths of up to 27 metres (89 ft) and is accessible to small boats from the east.
The public source identifies “Second Thomas Shoal” as reef in the South China Sea. This brief keeps that definition visible, then builds a research path around Second, Thomas and Shoal.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Second Thomas Shoal”, the useful work is to connect “reef in the South China Sea” to the records capable of establishing context and consequence.
Place names and jurisdictional language are key evidence: both can reveal earlier catalogue descriptions and overlooked record series. The source revision retrieved here is dated Aug 15, 2026. The linked authority identifier is Q6855008. Authority coordinates are 9.650, 115.850. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1999.
Modern boundaries and familiar names can conceal earlier jurisdictions or structures that do not align with the present site. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
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Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Second Thomas Shoal”, its source revision and the description used here.
- Expand the search: follow Second Thomas Shoal primary sources, Second Thomas Shoal archive and Second research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
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Search terms from this dossier
This entry incorporates text from “Second Thomas Shoal” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.