I've done many "sea" mixes over the years and I keep coming back to them because ambient music perfectly captures the impression of an undulating a sea or ocean.
00:00 Rafael Anton Irisarri - Displacement
03:52 Loscil - Angel of List
10:00 Kane Ikin - Slow Waves
13:30 Budd & Eno - An Echo of Night
15:20 Diatonis - Moving in Silence
19:54 Wave Temples - Under the Crystal Waters
20:25 Wave Temples - Thru the narrow strait...
21:45 Benoit Pioulard - Stanza II, IX
26:36 Spheruleus - Clouds Swarm
30:37 Purl - Havets Sång
36:50 pjusk & sleep orchestra - Daithn
41:12 Intrusion - Under the Ocean
44:50 Porya Hatami - Farewell
52:25 Pan & Me - The Sea Is So Quiet
59:00 Stefan Paulus - Salt Sea Island