Boats and boat with chests do not block the rendering of sculk sensor, calibrated sculk sensor and sculk shrieker.
Linked issues
relates to 4
MC-262761
Boats and boat with chests do not block the rendering of decorated pot
Resolved
MC-118561
Translucent blocks don't render through the inside of boats on any graphics setting
Open
MC-200473
Boats do not block the rendering of intersected lava
Resolved
MC-248995
Boats do not block the rendering of seagrass, kelp and corals
Open
Why do you expect them to stop the rendering? Because water stops rendering? Water and sculk blocks have nothing in common.