What does "secure the sail" mean?
This is taken from Sinbad TV-show: "Pull! Secure the sail!
Can you hold it?
Come on, help me!
Come on, help me!
We need to secure the sail!
Man the tiller now!
Man the tiller!
Steer into the wave!
Hurry, Sinbad, hurry! Into the wave!
"

Question

Answer

Hi Sasha.

The sail is the large cloth or tarp which catches to wind and propels a sailboat through the water.

Here, "secure" means "to tie down" or "hold down".