Historical clue formulations

• Echolocation technology — 2026-06-09
• Underwater tracking aid — 2025-06-23
• Source of a pulse — 2025-03-05
• Ping maker — 2025-01-17
• Aid in seafloor mapping — 2024-07-28
• Technology used in seafloor mapping — 2024-06-20
• Military technology that's a source of stress for whales — 2024-05-14
• Naval acronym — 2024-03-01
• Dolphin's facility — 2023-08-26
• Bat signal — 2023-07-01
• Submarine device — 2021-04-19
• Echolocation method — 2019-07-14
• Sub system — 2019-05-15
• One method of locating schools — 2018-12-15
• Salvage ship's detection system — 2017-09-20
• Whale facility — 2017-03-18
• Capability of whales and dolphins — 2016-12-24
• Sub standard? — 2016-10-21
• Submarine detector — 2016-06-20
• Echolocator — 2016-02-28
• Marine detector — 2015-12-05
• Echolocation device — 2015-09-13
• It might pick up a big fish — 2015-04-21
• Dolphin facility — 2015-01-10
• Ping maker — 2014-10-12
• Submarine sensor — 2014-06-24
• Torpedo detector — 2013-01-31
• Echolocation acronym — 2011-09-20
• School locator? — 2011-05-26
• Aid in finding sunken ships — 2010-12-07
• Red October detector — 2010-10-06
• Detection device — 2009-05-14
• Sub's navigational aid — 2008-10-13
• Underwater wave generator — 2007-12-12
• School locator? — 2007-11-13
• Sunken ship finder — 2007-10-29
• Ocean explorer's aid — 2007-06-14
• Coast Guard equipment — 2006-10-05
• Salvaging aid — 2006-08-11
• Deep-sea fishing aid — 2006-04-16
• Submarine-detecting system — 2006-01-30
• A school might be found using it — 2005-09-18
• School locator — 2005-06-12
• Kind of signal — 2005-05-22
• Sub finder — 2005-05-09
• Salvage ship's equipment — 2005-03-15
• Salvaging aid — 2004-12-10
• Bat signals? — 2004-09-11
• Aid in removal of mines — 2004-07-31
• Whale spotter — 2004-01-09