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The Tigers are 19th in the table after Monday's 1-0 defeat at Middlesbrough.
They had only 13 senior players available on the opening day of the season, and signed six in the last two days of the summer transfer window.
"Our signings have done their bit but they were last minute," said Davies. "I don't believe the manager had time to explore all of his options."
Mike Phelan succeeded Steve Bruce as Hull boss in July but was only given the job on a permanent basis in October.
The Tigers have scored only 11 league goals this season, fewer than any other team in the top flight.
"We need someone who can put the ball in the net," added Davies.
In a dour affair at the Riverside that was settled by a Gaston Ramirez header, Phelan's side did not seriously threaten the home goal until injury time.
"Our first shot on target was in the 92nd minute and that is not good enough," said Davies, who described his side as "gutless" and "embarrassing" after a 6-1 defeat at Bournemouth in October.
Hull, who have lost eight of their past 10 league games, were without six injured players and the suspended Dieumerci Mbokani for the trip to Boro.
"Hopefully come January we will look different," said Phelan.
"We need that investment. We can't afford any more injuries, it is going to be a hard slog throughout Christmas."

Building work at Wrexham Cemetery will see the restoration of Grade II-listed chapels and a lodge, which has been closed over safety concerns.
Wrexham council warned there would be some disruption, with paths, fencing and entrances also being improved.
It comes after the cemetery won a £1.1m grant from the Heritage Lottery Fund.
Councillor David A Bithell, lead member for the environment and transport, said work on the cemetery, which is on the register of Historic Parks and Gardens of Wales, would be completed in 2017.
The council said it was one of the finest examples of a Victorian cemetery in Wales with a well-preserved "gardenesque" cemetery landscape which was typical of the time it was created.

He called for more sobriety in a world obsessed by "consumerism and hedonism, wealth and extravagance".
The Pope was celebrating a Christmas eve Mass in St Peter's Basilica in front of about 10,000 people.
Later on Friday he will deliver his traditional Christmas message from the central balcony of St Peter's Square.
Celebrating Mass, the Pope said Christmas was the time to "once more discover who we are".
He called on believers to show the same simplicity as the child Jesus, "born into poverty in a manger despite his divinity" to inspire their lives.
"In a society so often intoxicated by consumerism and hedonism, wealth and extravagance, appearances and narcissism, this child calls us to act soberly, in other words, in a way that is simple, balanced, consistent, capable of seeing and doing what is essential," he said.
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"Amid a culture of indifference which not infrequently turns ruthless, our style of life should instead be devout, filled with empathy, compassion and mercy."
Security was tight at the service with police carrying out spot checks in the area surrounding the Vatican. Everyone who went into the basilica, the largest church in Christendom, had to pass through metal detectors.
Correspondents say the Pope, 79, used his homily to reflect the key themes of three years in office - mercy, compassion, empathy and justice.
"In a world which all too often is merciless to the sinner and lenient to the sin, we need to cultivate a strong sense of justice, to discern and to do God's will," he said.
His voice was occasionally hoarse - the effect of a slight flu earlier this week.
Hull City need help as they fight to avoid relegation from the Premier League, says defender Curtis Davies.
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A £1.5m refurbishment of a cemetery - hailed as one of the finest examples of a Victorian burial ground in Wales - could start in August.
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Pope Francis has warned the world's 1.2 billion Roman Catholics not to be "intoxicated" by possessions in his annual Christmas homily.