The Royal Naval Volunteer Reserve (RNVR) was a reserve component of the British Royal Navy (RN). It was created in 1903 has a mean of increasing rapidly the number of officers by absorbing a reservists who had already received a level of training.
Unlike their counterpart in the Royal Naval Reserve (RNR), officers of the RNVR were not professional mariner (although a fair number were yachtsmen) but rather people who volunteered to undergo part time naval training.
It ceased to exist in 1966 when it was amalgamated with the RNR. Although the new organisation would retain the name Royal Naval Reserve, the modern day RNR is, in many ways, a direct continuation of the RNVR with professional mariners now almost solely concentrated in the RNR's Amphibious Warfare Branch.
With only a few cosmetic differences, uniforms worn by members of the RNVR followed the same pattern and regulations as the RN
The only distinguishing marks of ratings and petty officers of the RNVR was an embroidered patch with the letters RNVR on the right sleeve.
Like their RN counterpart, midshipman wore a patch with a button on their lapel but theirs was maroon.
The shape of the stripes worn by officers lead the RNVR to be called "The wavy navy" by their full-time colleague, somewhat derogatively. This might be part of the reason why neither the RNVR nor the RVR type stripes were retained when the 2 were amalgamated.
Like in the Royal Navy, branches of service were indicated by either colour or letters added to the the basic rank stripes. Below is only a limited number of those known to have existed.
Note that Commodore 2nd class was the highest rank someone could achieve in the reserve.