Another question on rear blower vents

Noticed yesterday that only one vent throws air when blower is on. I see that the blower has one hose
directly connected to the one vent and the other three vents' hoses are just hanging free. Is this normal?
Feeling under the exhaust it seems as though there is zip tie and tape at free end of hoses but I cannot
tell what they would have connected to. Any ideas? Thanks.

This is normal. The other two just vent from lower in the bilge area.

Thanks a lot Dan. I thought that might be
the case but feeling a zip tie and tape on
the free ends got me thinking it was connected
to something at one time.