[[File:R-18 stbd.jpg|left|500px|Photo NH 108240 via NHHC.]]
<div style="text-align: justify;"><span style="color:#00008B">R-18 underway in a gentle swell off Hawaii, mid 1920's. The wires running fore to aft were radio aerial wires. The thinner one, when raised in conjunction with the radio mast provided long range communications. The heavier wire was for shorter range work, and would double as a mine clearance wire should the boat find itself in a minefield. The purpose of the sheet attached to the forward wire is not known.</span>
The USS R-15 seen in the Panama Canal. The date is between September 1918 and December 1918 when she and her sisters R-16, R-17 and R-18 patrolled Panamanian waters in the closing months of WW I. She has just finished backing away from either a pier or maybe a tender and is slowly gaining headway. The exact location is in some doubt, but the area seems to fit the Rio Chagres vicinity with the rail lines in the background and pairs of power poles as a clue. The WW I time frame is pretty certain due to the fact she is armed with the 3"/23 caliber Mk 9 gun (the gun barrel is mixed in with the legs of the two Chiefs in front of the conning tower), which she carried for only a short time. After her return from Panama, she and her sisters went to Mare Island to have the small guns removed and get deck modifications to accept the new, much more powerful 4"/50 caliber Mk 9 gun she will receive once she reported to Pearl Harbor.
R-16 underway with the hills of Oahu in the background, mid-1920's. The Pacific Fleet Submarine Force developed a visual scheme to aid in identifying the R-boats while they were on the surface. The scheme consisted of a series of geometric shapes. For R-16 the shape was a circle, and this is shown on the aft end of the fairwater. The scheme was only used for a few years in the 1920's.
A colorized photo of R-17 underway in an unknown location, possibly Pearl Harbor, early 1920's. For a short period during the homeport transition from the mainland to Hawaii, the R-boats did not carry any external identification, other than the non-official geometric shapes on the aft end of the fairwater. R-17's shape was a triangle, so we know this is her.
R-18 underway in a gentle swell off Hawaii, mid 1920's. The wires running fore to aft were radio aerial wires. The thinner one, when raised in conjunction with the radio mast provided long range communications. The heavier wire was for shorter range work, and would double as a mine clearance wire should the boat find itself in a minefield. The purpose of the sheet attached to the forward wire is not known.
