G'day Charlotte,
We have used the the Security Hangers that Pelagic posted above.
The drawing that we have hanging in Sobraon's Saloon is an rare artwork of the original Sobraon drawn by a very good friend. It has a heavy bronze and timber frame and measures 3ft x 3ft. We have had it on the bulkhead for 5 years and have been in some very big seas and it has never moved.
We purchased ours from a framing supplier and they were not expensive. The also allow you to unlock and remove the picture if you need to.
Fair winds
Garry and Wendy
SV Spirit of Sobraon
Spirit of Sobraon - www.sobraon.talkspot.com