Mr Rennie, the former MP for Dunfermline and West Fife, tabled a motion during Saturday's gathering, which was held in Dunfermline.
He told colleagues the £5.4 billion contract to build two new carriers for the Royal Navy was vital for the survival of shipbuilding in Scotland.
Work on sections of the HMS Queen Elizabeth has already begun at yards around the UK, including Rosyth Dockyard, where 1400 people work.
The sections are due to be shipped to Rosyth for final assembly. However, workers at Rosyth and on the Clyde are waiting anxiously for the outcome of the UK Government's strategic defence review.
Some have suggested the carriers might have to be axed to help the Ministry of Defence balance its books as cutbacks begin to bite. The results of the review are due to be published next week.
Mr Rennie, who is standing for the Scottish Parliament next year, told delegates he was convinced the project should proceed for the good of the country.
"I am a regular visitor to Rosyth Dockyard," he said. "You cannot but be truly impressed by the sheer scale of the task planned with the construction of the two largest ships ever built for the Royal Navy-65,000 tonnes of modern defence capability will be sailing down the Forth, only two miles from this conference hall, in just a few short years.
"I met the workers that will commission the ships, I've seen the plans and I witnessed the enormity of the newly extended dry dock where the work will be completed. That is if we let it. The power is in our hands. We can decide the future of the CVF."
"We can determine the fate of thousands of skilled shipyard workers here in Rosyth and over at the Clyde. It is our government that will decide."
Mr Rennie turned his fire on Labour, insisting the conditions for such a decision could not be more unfavourable.
"A gap of £155 billion between the money the government receives and what it spends, and that's just this year alone. A massive overspend on the defence procurement budget of £35 billion.
"Commitments given to projects without the finance to back it up is an act of sheer recklessness from a Labour government that professes to be the supporters of our dockyards.
"The Labour Government left our public finances in a truly shocking state. They hadn't even worked out how to pay for the planes that would fly from the carriers before they gave the go-ahead.
"What's worse is that only a matter of months after they signed the main contracts did they decide to delay the carriers for up to two years, costing the taxpayer an additional £1 billion. It is us that have been left to pick up the pieces, to make the sums add up and to determine a sensible defence and security strategy at the same time."
He concluded by saying, "I firmly believe that a versatile, flexible sea-based force can deliver significant value for money in terms of supporting policy, especially in preventing rather than fighting wars.
"A key component of that force would be the two new aircraft carriers, providing flexibility across the spectrum of operations as well as providing an air base when none are available ashore.
"Please support this motion, support Rosyth and the Clyde and support a robust and effective defence and security strategy for the UK."
Fife councillor Gerry McMullan backed Mr Rennie's call, saying, "These carriers are vital to transport men, aircraft and supplies quickly and efficiently and we have a constitutional duty to protect every man, woman and child in the UK."
"I am fully supportive and committed to the full contract of the carriers being built here in Fife and the Clyde."