A firm hand on the tiller American singular noun
The adjective "firm" sometimes can be replaced with the word "steady".
To describe a situation that is well-controlled or fully controled by somebody
Although we are having a firm hand on the tiller right now, we are not allowed to be careless at any moment.
A firm hand on the tiller is all what we need now.
Mind your business and keep a firm hand on the tiller!
A problem or difficult circumstance
a person who is easily deceived or manipulated to do something, especially giving someone money.
The noun phrase "A firm hand on the tiller" has its plural form which can be written as "Firm hands on the tiller".
This big project requires our firm hands on the tiller.