A survey of 220 marine industry executives from across the world also found that there is a lack of clarity around collisions involving unmanned ships, with 59% of survey respondents agreeing there is confusion surrounding the regulations in this area.
Clyde & Co explained the legal position where current international shipping law states that vessels must be properly crewed, which means that unmanned ships are not presently permitted to enter international waters.
However the issue is confused somewhat with the IMO announcement in June that it would begin to consider updating the International Convention for the Safety of Life at Sea (SOLAS) to allow cargo ships with no captain or crew to travel between countries.
The Comité Maritime International (CMI) has also this year established a Working Group on 'Maritime law for unmanned craft' to consider how international conventions and regulations can be adapted to provide for the operation of unmanned vessels on the high seas.
Clyde &Co partner Joe Walsh said: "The present state of SOLAS and collision avoidance regulations are being overtaken by and holding back potentially industry-changing technology from being developed and implemented."
He added: "Fortunately, the IMO, CMI and other industry interests appear to have recognised that there is a real appetite to test the water with unmanned ships at a commercial level. Industry will quickly need some legal clarity around cyber liability and collision regulations before any ground-breaking progress can be made."
Meanwhile IMarEST chief executive David Loosley said: "Technology is today advancing at an unprecedented rate and promises a host of new solutions for the maritime industry in terms of improved efficiency, safety and environmental performance. However, we should not be blinded by the benefits. We must also remain alert to the potential risks. This joint research report examines these vulnerabilities and how they might be addressed and is an important starting point for the industry to begin preparing for thefuture."
Concerns about cyber risk also weighed heavily in the considerations of respondents. Over two thirds (68%) fear that unmanned ships present a greater cyber security risk than traditional ships.
Clyde & Co and the IMarEST acknowledged that unmanned ships are likely to have a greater array of digital infrastructure than traditional ones, in order to ensure that shipowners and operators are able to control and track their ships remotely.
Walsh said: "Marine executives are right to be concerned about the potentially increased threat of cyber attack as a result of the use of unmanned ships. However, it is probably worth mentioning that the maritime industry as a whole has been criticised for being a bit slow in reacting to existing cyber threats, including fully crewed vessels and that the biggest threat to any organisation's cyber security posture is still, in fact, human error."
He suggested that "it is therefore possible that a transition to unmanned ships might actually reduce an organisation's profile and exposure to cyber risks".
"The cyber threat should certainly be taken seriously but it should not put the brakes on further exploration of the viability of unmanned ships," Walsh noted.
The report found that another key issue is the availability of insurance cover for unmanned ships. Four of every five (80%) survey respondents said it was unclear how insurers will approach new technology.
Patrick Murphy, partner at Clyde& Co, said: "For a business to implement any new technology there is always a certain 'leap of faith' moment, especially when that technology could significantly change the way that organisation operates. Suitable insurance cover can help make this a much more calculated jump into the unknown."
While the International Union of Marine Insurance (IUMI) has been discussing the implications of the new technology, there have not yet been any firm conclusions.