Hello Alex
Here are my informations about your questiones

On 13. / 14.09.1943 ( in my source Kemnade - Die Afrika Flottille date is 12./12.9.1943. ) the german s-boats S-57, S-158, S-151 ans S-152 capture two italian motorsailing vessel on italian west coast (Tyrrhenian Sea ), and brougt then in harbour Civitavechia.No other informations about these ships

On 09.01.1944. ( 8./9.1.1944.) S-36 and S-55 capture two yugoslav partizans motorsailing vessel and sink them with demolation charges and artillery.

On 9./10.01.1944 S-36 and S-55 capture one motorsailing vessel. The vessel is shortly after the capture sunk by british aircraft together with S - 55.

On 10./11.05.1944 S-30 and S-61 sunked near Cape Stončica ( entrance in Vis harbour ) yugoslav partizan hospital ship named MARIN II.Ship was unarmed and 250 tons.

You wrote: on 21.05.1944 S-30 and S-61 sink a partizan boat. This information is not correct because on that date S - 30 was in Pula ( damadges on motor ) and S - 61 was together with S - 36 in Greek waters near Otrant pass. They have battle with one british destroyer,

On 31.5./01.06.1944 S-158, S-153, S-155 and S-156 sink 3 motor cutter, 1 coastal motorship and a tankship. In book Die Afrika Flottille stays that 5 german Schnellboots from 7. Schnellbootsflottille sunked these boats and in Yugoslav maritime encyclopedia stay that 5 german Schnellboats captured on that night 3 yugoslav partizans motorcutters ( names : PALMA, SOKOL I SLOGA ) and two small wooden ships.

On 1. / 2.06.1944 S-158, S-153, S-155 and S-156 sink 3 motor cutter.
in book Die Afrika Flottille stays that 5 german Schnellboots from 7. Schnellbootsflottille captured 2 partuzan mottor cutters and sunk one mottor cutter,
in Yugoslav maritime encyclopedia stays that 3 german Schnellboots captured partizan motor cutter MALI ANTE, small cutter SV. ( Saint ) JURAJ and one small wooden ship.
Also on the same night S 153, S 155, S 156 and S 157 have battle with partizan armed boat NB - 8 KORNAT ( fisher boat, 61 tons, 19.5x5x2.4, 150 HP, 9 kts, armed with : one 40 mm gun, tree 20 mm guns and tree 8 mm FIAT machine guns, Crew : 24 ). German boats must withdraw with damages.


I also have information that 2 german Schnellboots sunked on 16. january 1944. two partizan motor cutters near island Vis, and that on 19. january 1944. four german Schnellboots sunked partizan motor cutter near islan Vis.
On the night of 17./18.3.1944. S 36 and S 61 sunked near island Lastovo partuzan armed ship NB - 2 ( ex german HZ - 9, fisher boat, 120 tons, 25x6x2.5, 240 HP, 11 kts, armed with : one 40 mm gun, two 20 mm guns and two 8 mm FIAT machine guns, crew : 14. )
On the night of 14./15.9.1944. S 154, S 152 and S 158 captured partizan patrol boat PČ - 73 PIONIR ( motor boat with one machine gun FIAT 8 MM and four members of crew).

If you have some other questions this is my email adress, so you can write me direct : jurica_vucetic@yahoo.com