“The Royal Adelaide was an iron sailing ship of 1400 tons built by William Patterson at Bristol in 1865”
This looks like it should be an easy enough dive to do from the shore, but that is not totally accurate – the walk is a bit of a pain…
You will findo online some instructions on how to find this site, there is a transit that you can use.
Lots more information on Finstrokes
It looks like it is well worth a dive, and this is supported by the videos you will find on youtube. Apparently it is covered in triggerfish for some reason…
Here are some photos of how far away the walk is:
This photo shows the 3rd lamppost along lined up with the end of the entrance to the harbour.
Also, be aware that there can be a strong current – slack water on this side of the bay is 2 hours after high water Weighmouth.