A brief recount of another action in my ongoing Central Solomons campaign. This one was actually gamed prior to my other posts. I don't particularly like the added complication of hidden plotted movement so included in this recap is a description of how we handled the "hidden" aspect of sub movement. This scenario is based on an actual action in which the sailors on one of the DDs claimed to have used potatoes as weapons against the sub (this aspect was not modelled in the scenario). In the actual action the Japanese crew were supposedly caught napping on deck with the DD gaining visual at very close range. As the DD passed the sub her crew tossed potatoes like grenades on the deck scattering the crew.
RO-34 Encounter 4/5/1943
Ref: “Breaking the Bismarck’s Barrier” pg. 119
“Dark Waters Starry Skies” pg. 131
Time: 0200-0330
WX: Moderate breeze with moderate chops = Force 4. 15K wind. No moon layer @200’
USN Forces IJN Forces
Honolulu (flag) RO-34
St. Louis
Helena
Nicholas (flag)
O’Bannon
Strong
Chevalier
USN Mission: Patrol for Tokyo Express avoid loss to subs.
IJN Mission: Report enemy movement. Rescue downed aviators.
Notes: Torpedo dud rate: USN = 1-3 (D12), IJN = 1 (d12)
Special scenario sighting rule for RO-34: Use D20 with only odd rolls resulting in success. After enemy has been spotted revert to D12s for remainder of the scenario.
Setup:
IJN: Sub is initially on surface. Course any desired, spd 10 kts. Initial range to lead US ship is 12000 yards.
USN: Course 000, spd 15 kts, formation CLs in line ahead DDs as desired within 3000 yards of CLs
Results:
RO-34 on picket/rescue duty. USN force of 4 DDs and 3 CLs on patrol up slot to NW of Vella Lavella. Initial contact of USN force occurred to late for the sub to gain a firing position on any US ship. USN DDs held radar contact but chose not to close and engage as cruisers had already passed the point where the contact could gain a firing solution. RO-34 was able to report contact to HQ at Rabaul. On return course to Tulagi USN DDs again contacted RO-34. One DD illuminated the contact with star shells at just over 5 kyrds while the other 3 opened fire with their forward 5" guns. No hits observed, and RO-34 executed an emergency dive. RO-34 remained at periscope depth and maneuvered to gain firing position on USN CLs. DDs executed ASW attacks resulting in minor damage to RO-34 and were successful in denying the sub a shot at the passing CLs. CLs increased speed to 32Kts to quickly exit the area.
Hidden sub movement rules, all other sub rules remain as detail in GQ 3.3
ASW scenarios without separate sub hidden graph plotting
- When submerged each sub is represented by 4 markers one of which is the real sub with the other 3 being decoys.
- Decoys will be moved just like actual subs but do not need to be plotted. Decoys do have to follow all movement rules as if they were real.
- Sub and decoys are placed per scenario specific instructions but as a general rule should be placed outside of visual/radar detection range.
- When making detection attempts vs decoy assume it is under the layer (if one exist in scenario) and use silent running if its move was 2kts are less.
- If a successful detection roll is made vs a decoy, the decoy is removed. If the attempt was successful vs a real sub, the marker is replaced by a “submerged sub token”. All decoys representing this sub that have not been previously removed can now be removed.
- Attacks can only be made against a real detected sub as represented by a “submerged sub token”.
- After the DC attack contact is lost and the “submerged sub token” is replaced by the 4 markers (representing real sub and 3 decoys).
- Should an undetected sub make a torpedo attack mark the launch point as normal and reposition or replace all decoys to the point of launch.
Sub are represented on the game table as follows:
- Day on the surface by actual sub model. Night on surface by 4 co located small markers which will move together. If detected visually all markers are removed and a sub model is placed. If detected by radar leave only one marker in place. Once a submarine submerges (even if detected visually or by radar) then the markers representing the sub and decoys replace the sub model at the submerge point.
- Day or night submerged undetected sub by 4 small markers. One representing the sub the others are decoys
- Day or night submerged detected sub by a “submerged sub token”
Order of movement for ASW engagements:
- When forces do not start in contact plot or pre-plot as required by GQ3.3 rules. Once in contact (i.e. a sub has been detected) then move in the following order:
- Plot and move surface units not in contact
- Plot and move sub
- Plot and move surface units in contact (declare any ASW attacks).
