The Landing Craft, Support (Small) was the American equivalent of the LCS(M), and actually was not that much smaller. Based on an LCP(L) hull, the LCS(S) had quarter-inch armour and a variety of weapons including twenty-four rockets in projectors mounted on the sides of the craft. Another twenty-four rockets were carried which could be quickly reloaded. After-action reports praised their use at Utah Beach but were less certain of their value at Omaha.
Above: At left, a pair of US Navy LCS(S)s off Utah Beach on 10 June 1944, showing the craft’s armour and protected cabin. They are respectively from APA-33 USS Bayfield and APA-13 USS Joseph T Dickman. In the background, an LCVP and an LCT(6). (Photo: US Naval History & Heritage Command 80-G-252689)
Some LCS(S) were operated by US Navy Scout and Raider units which functioned as control craft to guide the first assault waves to the correct landing site. After the assault, once the enemy was out of range, the Landing Craft, Support (Small) was used as a despatch and control craft.
Sources for more information:
Palmer Jr., William H.P., We Called Ourselves Rocketboatmen (no place: GoToPublish, 2018).