Many myths have grown up about what LCUs can and cannot do; here are the facts.
LCUs are capable of lifting all Marine Corps equipment, including two MIAI tanks (even those equipped with Track Width Mine Plows) in surf conditions up to a Modified Surf Index of 9 (during peacetime). The LCUs are little affected by environmental conditions as demonstrated during the recent USS Boxer (LHD-4)-15th Marine Expeditionary Unit (Special Operations Capable) deployment, and were a vital part of the mine-breaching operations for Exercise Kernel Blitz 97 at Camp Pendleton, California. During exercise Infinite Moonlight, one LCU conducted the entire backload of the 15th MEU(SOC) because the available ramp was obstructed for LCAC operations.
The LCUs carry 160 tons, while the LCACs can carry 60 tons on a standard day-and overload to 75 tons-but high temperatures have a significant effect on this capacity.
During Kernel Blitz 97, the USS Tarawa (LHA-1) carried four LCUs and the USS Peleliu (LHA-5) carried two; five LCUs were used during the pre-assault phase. Assault equipment needed for pre-assault/ breaching operations on a mined or obstacle-laden beach is almost exclusively weight limiting cargo, e.g., M1A1 tanks with mine plows, D-7 bulldozers, full width mine rakes. Tactically this equipment should arrive nearly simultaneously, both to sweep the beach more thoroughly and to provide mutual support.
Given reasonable proximity to the beach, an LHA configured with four LCUs can move significantly more cargo than one in the alternative configuration of two LCUs and one LCAC. The four LCU configuration used in Kernel Blitz resulted in a pre-boated load of four M1A1s, a full-width mine rake, amphibious construction equipment, and the entire landing force shore party/beach party platoon equipment load.
An LCU can operate independently for ten days or more, limited only by freshwater capacity; reverse osmosis units now being installed will eliminate this limitation. This endurance makes it a versatile platform. Rather than task a ship to act as a coastal monitoring platform, an LCU with a van on board can be positioned to provide electronic support measures surveillance. With a range of more than 1,000 nautical miles, LCUs provide not only an over-the-horizon assault capability, but also independent diversionary assault or amphibious demonstration capabilities. They are excellent platforms for evacuation operations, requiring no reconfiguration, regardless of cargo. The craft immediately transitions from carrying equipment to carrying personnel.
As used in Kernel Blitz 97, the LCU was an excellent minelaying platform, and provided a mother-ship capability for other elements of the very-shallow-water explosive ordnance disposal teams. It can serve as tripwire for maritime interception operations, thereby saving ships for only those boardings where the merchant fails to stop, and it provides a training support platform for the amphibious ready group (ARG) as well as force-protection services. Offensively, the 13th MEU used LCUs to carry assault troops conducting simulated gas and oil platform attacks. Using two LCUs, the force executed a pincer movement under cover of darkness and conducted a classic double envelopment.
Another example of the LCU's versatility was its use as the logistics platform to support a Marine construction battalion on a remote island off the Alaskan coast this past summer. The operation will continue for several more years and the LCU's endurance is vital to its success.
LCU capabilities are not exploited during most of today's West Coast ARG deployments because of the prevailing opinion that LCACs are more useful in the Persian Gulf. Yet each ARG that has returned from deployment has stated that the LCU brought much more to the table than was originally thought. Commanders repeatedly expound upon the usefulness of the LCU both in the Persian Gulf and elsewhere. The lessons learned have not been passed along formally through either Navy (although this does seem to be changing) or Marine Corps channels.
The narrow perception of where an amphibious ready group will operate is a potentially dangerous one, since significant threats exist outside the Gulf. Many, if not most, of these areas have beaches that are well within LCU assault capabilities.