Is Metal Detecting allowed: NO.
You can view the state regulation HERE:
The Rhode Island Historical Preservation and Heritage Committee does not permit recreational metal detecting on land that is owned or control by the State of Rhode Island.
I also found a document that states: HERE
Metal Detectors and other location devices are restricted to designated areas during specific time periods.
(However, it does not mention the areas or the times.)
FMDAC Disclaimer: FMDAC assumes no responsibility for any person who knowingly or accidentally violates any state park regulation. Although FMDAC will try to keep this information current we cannot anticipate how each regulation will be interpreted by a specific park department, park employee or other government employee. It is the sole responsibility of each individual to know and obey the regulations of the park or area they are visiting and or metal detecting.