If you have time to deploy the raft before your boat sinks, release the raft manually.
First release the slip hook and heave the raft over the side to leeward.
Throw it overboard and haul off on the painter until the raft inflates.
In the event that the raft inflates upside down, it can be righted by use of the righting straps.
Bring the raft alongside, tie it up with the painter and board the raft as quickly as possible.
Remove your shoes and any sharp objects you might be carrying to avoid damaging the raft.