The offer of $25.75 per share for the Mobile, Alabama-based company, is at a premium of about 27 percent to its Friday close.
"We're committed to working with their (International Shipholding's) board of directors to hopefully begin discussions and quickly enter into a merger agreement," Liberty Chief Executive Philip Shapiro told Reuters in an interview.
Shapiro said the combined company would create a platform for larger growth.
"The combined entity would create a stronger and more competitive entity in a better position for future growth in the U.S. and international seaborne sector," he said.
Shapiro said he had not spoken to any International Shipholding executives after the offer was made.
"We would be pleased to meet with them to consider any non-public information that may support an improvement to our proposal," he said.Shapiro also refused to speculate on whether the proposed acquistion would lead to any job cuts.
An International Shipholding spokeswoman said the company would issue a statement in response to the proposed acquisition, later in the day. Earlier this year, Greek drybulk carrier Excel Maritime Carriers Ltd acquired Quintana Maritime Ltd for $2.45 billion.