Shipbuilding supports nearly 10,000 jobs in Scotland, and has grown in importance while other manufacturing has declined.
Yards at Scotstoun and Govan on the Clyde and at Rosyth on the Firth of Forth are busy on Royal Navy orders.
However, a new academic study shows the decline in employment by the Ministry of Defence, down by nearly a quarter in the past eight years.
The report was commissioned by the GMB union.
It said it makes the case for the Ministry of Defence to safeguard shipbuilding jobs by committing soon to a delayed order for eight frigates.
The research has been carried out by the Fraser of Allander Institute at Strathclyde University.
It estimates that 13,840 people are employed by the Ministry of Defence in Scotland.
In 2008, when the economics institute last reported on the defence sector, there were 23% more jobs in uniformed and MoD civilian roles.
The number of civilian MoD employees has fallen from 6,500 to 3,730 in eight years – a time of government budget cuts.
The number in military roles is down from 12,400 in 2008 to 10,100 this year.
The fall in military roles has been faster across the UK as a whole, meaning the Scottish share of jobs has increased slightly. However, the share of civilian employment has fallen to 8.5%.
GMB Scotland Secretary Gary Smith said: “This report was commissioned following the delays to type-26 programme and because of the long-term frustrations felt by our members across the sector after years of being used as a political football.
“One job on the Upper Clyde alone supports an additional 1.18 jobs across Scotland so for the future of Scottish shipbuilding and our long-term economic prosperity it is imperative that the UK government makes good on the promised frigate programme.
“Furthermore, and with a second independence referendum a real possibility, the Scottish government needs to demonstrate to our members how they would plan to sustain their jobs, wages, pensions, skills and local communities without MoD investment.
“This report is a reality check and shows that the fragile Scottish economy cannot do without the thousands of jobs and hundreds of millions of pounds in wages supported by navy shipbuilding contracts.”
The report shows that the share of jobs within Scotland are mainly in Argyll, with more than a third, and Moray, with a fifth.
Argyll has the Faslane and Coulport nuclear and submarine bases, while Moray has air and army operations based at Lossiemouth and Kinloss.
For those two council areas, military employment is particularly important, at 13% of the workforce in Argyll and Bute, and 8% in Moray.
A recent Scottish Enterprise survey, carried out with the defence sector, found it employs more than 38,000 people, including the Ministry of Defence, shipbuilding, aerospace and research.
The shipbuilding sector saw employment dip in 2011, before the aircraft carrier work got under way, and has since risen to 6,500.
In the five years to 2014, employment rose 4% while there was a 1% drop in manufacturing jobs. That means it accounts for one in every 27 manufacturing jobs.
Modelling by the Allander economists suggests there was initial employment of 2,700 jobs on the Clyde, supporting a total of 4,900. Once it is spent, the wage bill, of 93m, has a dynamic effect on the economy reckoned to be 163m.
A previous study by the same institute, using data from 2006, showed 4,500 jobs supported, and a dynamic impact of 238m.
In Fife, the new report shows there are 1,800 directly employed in shipbuilding, supporting a total 3,900. The wage bill is calculated at 60m, supporting 106m of spend.