तृतीया

तृतीया = त्रि + तीय + टाप्
object(float water) + float below connect + coracle
Meaning explained : coracle floats by connecting to water
comment: this seems ok but we need to consider what is not stated - coracle floats by connecting to water without rolling in wave.

द्वितीया is incoming wave
तृतीया is getting water under coracle, irrespective of tide