The most common and most likely answer to this crossword clue is the 4 letter word LOCK
I've seen this crossword clue in Independent
L
O
C
K
More clues leading to the result LOCK
- Something seen on canal or strand
- Curl / forward
- Secure temporary container for lighter, say
- Forward, notice, avoiding header
- One might pick this rugby forward
- Secure place with gates at both ends
- Forward and upward process for boats
- Return of Colonel K’s hairpiece?
- Secure strand of hair
- Piece of hair from player in scrum?
Buddy explains!

The straight part
We know that "Forward and upward process for boats" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case forward and upward process for boats = lock.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LOCK mean?
LOCK noun- Something used for fastening, which can only be opened with a key or combination.
- (by extension) A mutex or other token restricting access to a resource.
- A segment of a canal or other waterway enclosed by gates, used for raising and lowering boats between levels.
- The firing mechanism.
- Complete control over a situation.
- Something sure to be a success.
- A player in the scrum behind the front row, usually the tallest members of the team.
- A fastening together or interlacing; a closing of one thing upon another; a state of being fixed or immovable.
- A place from which egress is prevented, as by a lock.
- A device for keeping a wheel from turning.
- A grapple in wrestling.
- To become fastened in place.
- To fasten with a lock.
- To be capable of becoming fastened in place.
- To intertwine or dovetail.
- (break dancing) To freeze one's body or a part thereof in place.
- To furnish (a canal) with locks.
- To raise or lower (a boat) in a lock.
- To seize (e.g. the sword arm of an antagonist) by turning the left arm around it, to disarm him.
- To modify (a thread) so that users cannot make new posts in it.
- (WMF jargon) To prevent a page from being edited by other users.
- A tuft or length of hair, wool etc.
- A small quantity of straw etc.
- A quantity of meal, the perquisite of a mill-servant.