The U.S. Navy’s push to field swarms of autonomous surface vessels has suffered a series of mishaps that have stalled the high-profile program aimed at deterring a potential Chinese move on Taiwan. During a July test off the California coast, one experimental drone boat lost power because of a software fault and was rammed by another vessel, according to internal videos and people briefed on the incident. In an earlier trial, a support craft capsized when a drone it was towing abruptly accelerated, throwing the captain into the water. Following the accidents, the Pentagon’s Defense Innovation Unit placed an indefinite hold on a roughly $20 million contract with L3Harris, the company supplying some of the autonomy software. The Navy has also dismissed Rear Adm. Kevin Smith, who led its Program Executive Office for Unmanned and Small Combatants, and the unit itself is now under internal review. The setbacks come despite heavy spending intended to replicate the impact of relatively cheap Ukrainian sea drones. Washington’s $1 billion Replicator initiative and a separate defense bill signed last month allocate close to $5 billion for maritime autonomy. Procurement records show at least $160 million already committed to BlackSea Technology, while rival Saronic recently reached a $4 billion valuation. Analysts say overcoming software integration problems and organizational turmoil will be critical if the Navy is to deploy large numbers of self-piloted vessels in the timeframe envisioned by defense planners.